Pentax K-x Review

Overview

Pentax K-x Overview

Pentax announces its second digital SLR camera of 2009, the Pentax K-x, a new consumer digital SLR kit that's packed with features but with a sub-$650 price tag. Four body colors are available, the standard black or white, plus "special, limited edition" red and navy bodies.

Coming with an 18-55mm kit lens, the Pentax Kx is a 12.4-megapixel camera with sensor-shift image stabilization, a 2.7-inch LCD, Live View mode, and a 720p movie mode. Capable of 4.6 frames per second, the Pentax K-x's top shutter speed is 1/6,000 second.

Though the camera includes Pentax's 11-point SAFOX VIII AF system, it is hampered inexplicably by the lack of an AF-point overlay in the optical viewfinder, which means there's no visual confirmation of which points are in focus.

Surprisingly the Pentax K-x also includes the K-7's HDR modes, and it also has the Digital filters, as well as a new Cross Process mode that randomly emulates several results that you'd only get by cross-processing film with different types of developer.

Small and light, the Pentax K-x seems like a well-built, no-nonsense digital SLR, with perhaps only one flaw: the lack of visible AF points.

Pentax Kx price and availability. The Pentax K-x digital SLR will initially be available from October 2009 in three different kit versions, and two body colors -- either black or white. The most affordable kit version will include an smc Pentax DA L 18-55mm zoom lens for a total price of around US$650. Two twin lens kits will couple this 18-55mm lens with either an smc Pentax DA L 50-200mm zoom lens for about $750, or with a new smc Pentax DA L 55-300mm zoom lens for approximately $850. As with the previously announced DA L lenses, the new lens is a variant of an existing lens with certain alterations made to reduce weight and cost, such as the use of a plastic lens mount. Two unusual limited edition Kx body colors -- red or navy blue -- will also be available in limited distribution, with details on those versions to be announced at a later date.

Pentax K-x User Report

by Shawn Barnett and Mike Tomkins

After wowing us earlier last year with the Pentax K-7, we're surprised to see Pentax back at it so quickly with the light and nimble Pentax K-x. The Pentax K-x's list of features is impressive, including much of what was introduced on the K-7. The only potential downfall is the lack of an AF-point display overlay, something also missing from the K2000, which means that no LEDs will light up in the viewfinder when you half-press the shutter button to focus. Its omission leaves me scratching my head, and threatens to color the tone of our review. Since almost every other camera on the market gives some kind of indication of what areas are in focus before I commit to a shot, this just feels like I'm using a broken camera. While the K2000 also didn't have indicators, it didn't have 11 autofocus points covering a large percentage of the frame, so the potential for error was smaller.

Look and feel. The Pentax K-x has very nearly the same body as the K2000. A few buttons are reassigned to accommodate Live View and Movie modes. When loaded with lithium batteries, the K-x weighs 20.5 ounces (581 grams) -- a full six ounces (170 grams) lighter than the magnesium alloy-bodied K-7. A significant part of that savings comes thanks to the Kx's use of a fiber-reinforced plastic polymer body over a stainless steel chassis, and the exclusion of any weather sealing. The K-x's body is also about 0.2 to 0.3 inches (5 to 8 millimeters) smaller in every dimension than the K-7, and is among the smallest true digital SLRs available.

Though it's small, the Pentax K-x's grip is good, with an ample thumbgrip on the back. The notch for the middle finger is a little too small, but I'm glad it's there. Just under the X in Pentax there's a hole for the microphone to accommodate movie mode. An infrared port is imbedded into the grip.

On the top deck, you can see the two speaker holes just left of the flash. The Mode dial now includes Movie mode; unfortunately, it also turns too easily, accidentally jumping from mode to mode as I move it in and out of my camera bag. What was once the "?" or help button on the K2000 is the Green button that re-centers exposure and metering settings depending on the mode.

The Info and Menu buttons have moved down to make room for the LV (Live View) button, and the Flash pop-up button now doubles as the Delete button when in Playback mode. From here you can also see the power indicator lamp on the top deck, which shines a bright blue instead of the K2000's green.

A new graphical Status display not only outlines the camera's current exposure settings, but shows the current settings for four of the five navigation buttons on the camera's lower right, a great use of the large LCD. With a glance you can see that in this case the camera is in Single shot mode, Custom white balance, Center AF point, and Manual Flash-on (when the flash is popped up). Only the ISO button remains unchanged, since the ISO status is displayed to the left.

Sensor and processor. Compared to the K2000, the Pentax Kx upgrades both the image sensor and processor. The Pentax Kx's RGB Bayer-filtered 3:2 aspect ratio CMOS image sensor has 12.4-megapixel resolution, placing it exactly halfway between the resolutions of the 10.2-megapixel K2000 and 14.6-megapixel K-7.

With dimensions of 23.6 x 15.8mm, the new sensor is approximately the same size as a frame of APS-C film, and a fraction of a millimeter larger in each direction than those used in the K-7 and K2000.

The new imager is coupled with the company's latest generation PRIME II image processor, which debuted in the K-7 and offers improvements in both speed and image quality. Impressively, the Pentax Kx bests the equivalent ISO sensitivity offered by both the K-7 and K2000, with a maximum sensitivity of ISO 6,400 which can be expanded to ISO 12,800 if needed.

Shake Reduction. The image sensor of the Pentax K-x is mounted on a moveable platter which allows it to be used to provide for sensor-shift shake reduction, helping to reduce image blur from camera shake. Unlike lens-based systems, the Pentax K-x's in-body stabilization functions with pretty much any lens that can be attached to the camera. Pentax's marketing materials claim the system offers a potential four-stop improvement -- the same as that of the K-7 and K2000.

Like almost all shake reduction systems, the Kx's shake reduction can correct only for horizontal or vertical motion, but not for rotation -- a rare capability that is offered by the K-7. In place of the newer ultrasonic DR II system from the flagship, the K-x retains the previous generation of dust removal as seen in the K2000. This dual-pronged approach couples Pentax's Super Protect fluorine coating on the low-pass filter to help prevent dust adhesion, and use of the sensor-shift mechanism to shake dust particles free. The K-x also includes Pentax's Dust Alert function, which helps the user determine the location of any dust on the sensor for manual cleaning.

Lens mount. On its front panel the Pentax Kx features a stainless steel Pentax KAF2 bayonet mount which allows use of KA, KAF, KAF2, or KAF3 lenses. The K-x can also accept K-mount, 35mm screwmount, and 645 / 67 medium format lenses with an adapter and some usage restrictions. The Kx is compatible with Pentax's Supersonic Drive Motor (SDM) lenses, but doesn't support power zoom functionality on lenses with this feature.

Viewfinder. The Pentax K-x retains the K2000's pentamirror viewfinder with 96% coverage and 0.85x magnification, as well as its 2.7-inch LCD display with 230,000 dot resolution (translating to roughly 320 x 240 pixels, with three dots per color). Unlike the K2000, however, the Pentax K-x offers a Live View mode which operates on data streamed from the image sensor, enabling images to be framed on the LCD display.

Autofocus. The Pentax K-x uses an 11-point SAFOX VIII phase-detection autofocus sensor, which offers nine cross-type points. The same autofocus sensor has featured in quite a few of the company's digital SLRs since it launched in 2003's *ist D, Pentax's first digital SLR. Indeed, the flagship K-7 still uses a similar sensor, although it supplements it with a dedicated AF assist lamp and a secondary light color sensor, as well as refined AF algorithms. It's a significant upgrade from the five-area AF system of the K2000. As we mentioned, though, there are no AF in-focus indicators in the optical viewfinder to show which AF point or points are selected.

Live View. In addition to phase-detection AF, the Pentax Kx offers contrast detection autofocus with face detection capability when used in Live View mode. Like the K2000 before it, the Pentax Kx performs exposure metering with a 16-segment sensor, although the sensitivity range of EV1 to 21.5 (ISO 200 with a 50mm F1.4 lens) differs slightly from the EV0 to 21 range quoted for the predecessor camera.

Exposure. The Pentax K-x offers quite a selection of exposure modes, with varying degrees of control from fully automatic to fully manual shooting. The Mode dial on the Pentax K-x's top panel provides direct access to the camera's Program and full Manual modes, as well as three Priority modes which allow the user to control either Aperture, Shutter Speed, or Sensitivity while leaving the remaining variables under automatic control.

Six Picture modes merit their own positions on the Mode dial for ease of access, including Portrait, Landscape, Macro, Action, Night Scene Portrait, and Standard Flash Off modes. Also found on the Mode dial are one position each for the Scene, Auto Picture, and Movie modes (more on this last choice in a moment). When set to Auto Picture mode, the camera automatically selects between the same six Picture modes just mentioned. The Scene position, meanwhile, allows one of ten modes to be selected on the camera's LCD display: either Night Scene, Surf & Snow, Food, Sunset, Kids, Pet, Candlelight, Museum, Stage Lighting, or Night Snap. Both the Stage Lighting and Night Snap modes only allow images to be saved as JPEG files.

Shutter speeds on offer in the Pentax Kx range from 1/6,000 to 30 seconds plus a bulb mode, and impressively for an affordable camera, Pentax is rating the K-x's shutter mechanism as good for around 100,000 shots. Most digital SLRs at this price range max out at 1/4,000 second, and none spec an approximate shutter life.

Fast burst rate. Another impressive capability of the Pentax K-x is its burst shooting mode. With the company's flagship Pentax K-7 capable of shooting at 5.2 frames per second, the full-res 4.6 fps offered by the Kx really isn't a whole lot slower. When shooting at this maximum rate, burst depth is limited to five RAW or 17 JPEG frames. (We measured 4.32 fps for 25 JPEGs and 4.55 fps for 5 RAW frames.)

White balance. The Pentax K-x determines white balance using its image sensor, and offers both Automatic and Manual modes, plus ten presets including the new Color Temperature Enhancement mode introduced in the K-7, which is used to retain and enhance the lighting tone -- for example, to enhance a sunset.

Creative modes. The Pentax Kx also offers a range of functionality for photographers looking to unleash their creative side without the need for a PC. The High Dynamic Range shooting mode which debuted in the K-7 makes a repeat appearance, allowing several bracketed exposures to be combined in-camera to form a single image with increased dynamic range. When the K-7 was launched, Pentax was unique in providing this feature in a DSLR, but Sony has since included a similar function in its A500 and A550 models. Each company's approach has advantages and disadvantages in operation.

Pentax's HDR mode captures three bracketed images, allowing a greater dynamic range to be covered with its mode, where Sony captures just two source images. In turn, though, Sony's HDR mode takes significantly less time to process, and yet is capable of micro-aligning images to allow for handheld shooting, where Pentax's mode requires use of a tripod. (In both cases, a relatively static subject is needed to prevent artifacts in the final image).

In addition to HDR photography, the Pentax Kx allows in-camera processing of RAW files, and as with the K-7 it also offers a wide range of digital filter and custom image modes that give the photographer a significant amount of control over the final look of images. One function newly added since the K-7 is Pentax's Cross Process mode, which is intended to offer a similar effect to the film processing technique. Cross processing of film involves intentionally using processing chemicals with a film type for which they weren't intended, with unpredictable but sometimes eyecatching effect. The Cross Process filter in the Pentax K-x makes quasi-random changes to an image, with the final effect unknown until it is shown on the camera's display.

Movie mode. The Pentax K-x also offers the ability to shoot high-definition movies, much like the K-7 before it. The main differences are that the K-7's non-standard maximum resolution of 1,536 x 1,024 pixels and its external microphone jack have both been dropped, and the frame rate reduced slightly from 30 to 24 fps. Otherwise, the mode is quite similar, with videos recorded at resolutions of either 1,280 x 720 (16:9 aspect ratio) or 640 x 416 (approx. 3:2 aspect ratio), and then saved as AVI files using Motion JPEG compression.

Note that there's no high definition video connectivity on the Pentax K-x, so movies must be offloaded from the camera before they can be viewed in their full high-def glory.

Storage and battery. The Pentax Kx stores its images and movies on Secure Digital cards, including the larger and faster SDHC types. Still images can be saved as JPEG compressed or RAW files, with the K-x supporting both Pentax's proprietary .PEF and Adobe's .DNG RAW file formats.

Power comes courtesy of four AA batteries, with both alkaline / lithium disposables and NiMH rechargeables listed as being compatible. Battery life using the optical viewfinder is rated as 1,100 shots using lithium disposable batteries, to CIPA testing standards which include 50% flash usage. That drops to only 420 shots with NiMH rechargeables, which is below average for an SLR. Both NTSC / PAL standard-definition video output and USB 2.0 High Speed computer connectivity are included.

Shooting with the Pentax K-x

by Mike Tomkins

Having recently purchased Pentax's K-7 prosumer digital SLR myself, and spent the last couple of months growing familiar with its interface, I found the K-x to be a very comfortable camera to use overall. Much of its UI mirrors that of its higher-end sibling. I did miss having a second control dial, but that's to be expected in an entry-level camera, and you get used to it quickly. My first impression on handling the Pentax K-x was one of mild surprise at its heft, though. It's a fair bit smaller than the K-7, which is already fairly compact by DSLR standards. With batteries loaded and ready to shoot, however, the Pentax K-x wasn't as light as its dimensions might suggest. Using four Sanyo Eneloop (HR-3UTG; 2,000 mAh) AA batteries, body weight with no lens attached was approximately 22 ounces, only 4.5 ounces less than the K-7. By comparison, several of the Pentax K-x's nearest rivals from Canon, Nikon and Sony come in at around the 18-19 ounce mark without a lens, thanks to their use of rechargeable lithium-ion batteries.

None of this is to say that I found the K-x to be unwieldy; on the contrary, its weight was nicely balanced, and it fit comfortably even in my rather large hands. The Pentax K-x's body also felt reassuringly solid and sturdy for an entry-level camera, with little flex or creak in its fiber-reinforced polycarbonate panels, which are constructed around a stainless steel chassis.

Lens variety. Some of the K-x's heft is also cancelled out by the availability of several kit lens options which include the Pentax DA-L 18-55mm F3.5-5.6 AL lens, and in the two-lens kits, either the Pentax DA-L 50-200mm F4-5.6 ED or DA-L 55-300mm F4-5.8 ED lens. These lenses are optically identical to their standard DA equivalents, but somewhat lighter thanks to a few tweaks. The changes include the removal of the quick-shift feature (which allows focus to be manually adjusted after an autofocus operation on a DA lens without first changing the focus mode), and the use of a plastic lens mount rather than a metal one. Personally, I could live without the quick-shift AF function to save a little weight and cost, as I don't find myself using it that often.

My review kit included the DA-L 18-55mm lens, which I own in its DA WR weather-resistant version, and I found build and image quality to be pretty similar; certainly within what I'd expect for normal sample variation. I've not had the opportunity to try the other two DA-L lenses, but I also own the WR version of the 50-200mm lens and can definitely recommend it as an affordable, yet capable design.

Batteries. I have a feeling that a large part of the weight difference between the K-x and its nearest rivals comes down to its choice of batteries (and to some extent, my own choice of Sanyo's Eneloops, which I favor for their battery life and charge retention, but which aren't necessarily the lightest option). Pentax's K-x is the only current digital SLR that's powered by AA batteries, with all of its rivals having opted for proprietary lithium-ion rechargeables. Certain models -- including Pentax's own K-7 -- can accept AA batteries through the use of a portrait / battery grip, but this is very much a compromise, as the grip itself brings a significant increase in overall size and weight. If you prefer to avoid proprietary batteries, the Pentax K-x is your only choice.

The reasons I tend to favor proprietary lithium ion batteries are twofold: for their greater energy density (meaning less weight for equal battery life), and because in a rush (or in poor light) I find it significantly quicker to change one lithium ion cell than to fiddle with changing four AA cells, all the while paying attention to the orientation of each cell. I should note that I did occasionally experience two issues with my review K-x reporting low charge remaining on my freshly charged, brand-new Eneloops (even if the battery type was specified through the menu system), and with the camera simply refusing to power on after a change to fresh batteries. In each case, reseating the batteries or simply opening and closing the battery compartment door was enough to clear the issue. We had the same trouble in the lab. Updating the firmware to version 1.01 solved the issue. You can download the firmware update here.)

Continuous mode. Probably my favorite feature of the Pentax K-x is its burst shooting speed. With a burst rate of 4.7 frames per second for as many as five RAW or 17 JPEG frames (we measured a bit slower), the Pentax K-x is one of the fastest cameras in its class, and even nips at the heels of its prosumer sibling, the 5.2 fps Pentax K-7. My own shooting style is such that I tend to favor burst shooting not only for sports, but also in situations like shooting kids and pets. For example, while shooting with the K-x at my son's first birthday party in a dimly lit pizzeria, I could rattle off a burst of shots and then save the best ones. This both saved me having to trust the shot to my occasionally rather dubious reflexes, and ensured that with a large quantity of photos to choose from, I'd still have plenty of keepers despite lighting conditions that made focusing and framing more of a challenge.

High ISO. Equally useful in the same setting was the 12.4-megapixel Pentax K-x's high ISO capability, which noticeably outshines that of the more expensive Pentax K-7. In general usage, I find the K-7's 14.6-megapixel sensor to be too noisy above ISO 3,200, and tend to reserve higher sensitivities for when there's no alternative. See the samples below.

Pentax K7 (above) vs Pentax Kx at ISO 6,400.

With the Pentax K-x, I found I could get acceptable results at ISO 6,400, especially if shooting RAW and applying some noise processing in Photoshop. At lower sensitivities, what noise is apparent isn't really any more obtrusive than film grain, and I found myself using ISO 3,200 with surprising regularity during my time with the Pentax K-x. Having a usable high sensitivity is great for avoiding the use of flash, and yields much more natural looking shots.

Confirmation? The only thing that really stood out to me as a particular annoyance with the Pentax K-x is something we've mentioned several times elsewhere in this review, but it's something that bears repeating. Going into this review, I was aware that the Pentax K-x lacked any indication of autofocus point location or selection in the optical viewfinder, but I must admit I thought I'd get used to it and work around it quickly and easily. In actuality, the longer that I used the Pentax K-x, the more I found this design decision bothered me. With the Pentax K-x offering a smaller, dimmer pentamirror viewfinder than the K-7, I found it wasn't as easy to determine the exact focus point in low light.

Shooting at my son's birthday party was one example of conditions in which I'd have to give up on the Pentax K-x's 11-point AF system, solely due to the lack of a viewfinder indication. The problem was that with no indication of the active focus point, I wouldn't catch that the K-x had decided to set focus in the wrong place. Setting the focus point manually was too slow, however, requiring me to take the camera away from my eye each time I wanted to change the active point. Hence, I'd end up just using the central point to lock focus with a half-press of the shutter button, then recompose the shot and trigger the shutter. For burst shooting, I'd prefocus on my subject's eyes and then trigger a burst of shots with AF disabled. A large proportion of the shots where I got lazy, letting the camera determine the focus point for me instead, ended up having to be discarded because focus was set in the wrong place.

This is all particularly disappointing because I found the Pentax K-x's autofocus system perfectly capable of locking focus correctly in pretty low-light; certainly, as dim as I'd be capable of shooting handheld without flash. That's not surprising, because the Pentax K-x uses basically the same AF sensor as the K-7, albeit without the extra sensor used to determine and account for color temperature of the light source when focusing. With eleven points, all but two of these being cross-type points, the K-x's AF system is fairly sophisticated for an entry-level camera at its price point. Hopefully, Pentax will see fit to add AF point illumination in the K-x's successor, because it would make this AF system significantly more usable (and hence, useful).

Sensor movement? We've seen some talk in photography forums about shutter-induced blur with some Pentax Kx units when shooting around 1/100 second with SR on, and mostly vertical, but we haven't noticed any examples among our images captured during our review, as we did with the Olympus E-P1. So we took some informal shots to see if we could reproduce the error with handheld shots. We saw the image-doubling issue in about one out of ten shots at 1/100 second. Our best example was captured in horizontal orientation, though, not vertical as we'd expected. Look closely and you can see that all the horizontal lines have a slight ghost image a few pixels down in this 100 percent crop. Might the sensor be shaking in response to the vibration of the shutter or mirror mechanism? Or perhaps the SR system is responding to the vibration. The third and fourth possibilities are movement of a lens element or photographer movement. These were captured with the 43mm Limited lens, which in our experience is rock solid, so that's probably not it. It could also be photographer motion, but the shift seems more of a distinct, mechanical movement, not as much a blur. At least in our unit, it's not a large issue, as we didn't notice it in any of our test or Gallery shots; then again, it didn't take much to reproduce the phenomenon. We'll leave it to you to decide whether it's an important issue for you. All SR systems smear at some point, but we'd prefer it didn't happen at 1/100 second with a 43mm lens.

Pentax Kx Print Quality

The Pentax K-x's printed output is really impressive, able to make usable 20 x 30-inch prints at ISO 100, straight from the camera with standard noise suppression on. They're slightly soft in some places, tack sharp in others; a little sharpening in a program like Photoshop could make them even better. 16 x 20 images are about the same, with a little more sharpness than the 20 x 30-inch prints. The amazing part is that print quality remains this good up to ISO 800! Even our troublesome red swatch still looks better than most cameras do at ISO 800, even when printed at 16 x 20.

ISO 1,600 represents the first break from this remarkable print size, and it's also the first time the red fabric swatch begins to decay. Still, the rest of the detail looks fabulous, with just a little noise and noise suppression artifacts creeping in. Reduction to 13x19 at this size is a little better.

ISO 3,200 shots also look decent printed at 13x19 inches.

ISO 6,400 shots are generally usable at 11x14, remarkably, but of course better at 8x10.

Depending on the subject ISO 12,800 shots are usable at 8x10, though contrast is increased and there's some blotchy noise in the shadows. At 5x7 inches, though, no one will notice.

A truly excellent and surprising outcome from the Pentax Kx!

Pentax Kx Image Quality

Pentax Kx vs Pentax K7 at ISO 1,600

Pentax Kx at ISO 1,600	Pentax K7 at ISO 1,600
Even at ISO 1,600 the 12.4-megapixel Pentax Kx outputs generally smoother images than the 14.6-megapixel K7. This is largely due to noise reduction, but don't count the sensor out of this equation, as the Kx could be a higher-grade sensor than that found in the K7. Difference in resolution makes the point academic, really. But if you're looking for good quality images at high ISO settings, the Kx will deliver.

Pentax Kx vs Canon T1i at ISO 1,600

Pentax Kx at ISO 1,600	Canon T1i at ISO 1,600
Easily the Pentax Kx's greatest rival is the 15.1-megapixel Canon T1i, yet I think the Kx holds up quite well despite the difference in resolution.

Pentax Kx vs Nikon D5000 at ISO 1,600

Pentax Kx at ISO 1,600	Nikon D5000 at ISO 1,600
More evenly matched are the Pentax Kx and Nikon D5000, as both have 12-megapixel sensors. The Kx looks a little smoother in the shadows, surprisingly, and shows better contrast and detail in the mosaic shot. The D5000 renders the red leaf cloth much better, though, so you'll get more detail out of cherry red cars, for example. This is a particularly difficult test that most digital SLRs don't handle well, so it's not a major strike against the Kx.

See below for Pro/Con listing and Conclusion.

In the Box

The Pentax Kx comes with the following items in the box:

• Pentax Kx body
• Body mount cover
• 18-55mm lens (Kit version)
• Front and back lens caps
• USB cable
• Eyecup
• Hot shoe cover
• Strap
• Four AA lithium batteries
• Software CD ROM
• Operating manual
• Registration kit

Pentax K-x Conclusion

As I packed up my K-x review unit, I found myself in two minds as to whether I'd consider buying the camera myself. On the one hand, I could see it being a very useful second body to accompany my K-7 for low-light, high ISO shooting. On the flip side of the coin, for my shooting style I think the lack of AF point illumination would be hard for me to live with, and I'd prefer a lithium-ion-based camera with two control dials. Pentax's current DSLR lineup consists of just two models, but were they to offer an intermediate DSLR based on the K-x, with these three design points altered to my tastes, I'd very likely pick it up as a second body to accompany my K-7.  If you can live with the lack of AF point illumination, though, there's no denying that the K-x offers a lot of camera for the money. The Pentax Kx can take some mighty fine pictures, and offers compatibility with some truly lustworthy Pentax glass, including their flagship DA Limited lenses. The bottom line is that I'm not the target customer for the K-x. Regardless, the Pentax Kx has enormous value, thanks to its remarkable image and print quality, fine build, and class-leading burst speed, all combining to make one impressive digital SLR camera. The Pentax Kx is a Dave's Pick, with the warning that there are no AF indicators in the viewfinder. But for sheer image quality at a wide range of ISOs, the Pentax Kx is tough to beat, especially for the price.

Design

Pentax K-x Design

Roll-over the various controls and features with your mouse for a brief description. Note: Rollovers are best viewed with the latest versions Firefox, Safari, or Opera browsers, or Internet Explorer 6 or earlier.

Front View. From the front, the Pentax K-x is virtually identical to its predecessor, the K2000 / K-m. The only noticeable change beyond the model number is a tiny microphone hole tucked underneath the viewfinder prism.

Left View. The left side of the Pentax K-x is again almost identical to that of the K2000
with the exception of two tiny speaker holes in the side of the prism.

Right View. The right side of the Pentax K-x is basically indistinguishable from that of the K2000. (K-x shown here with kit 18-55mm lens.)

Top View. There are a few changes to the Pentax K-x's top deck compared to the K2000. The new speaker holes can again be seen on the left of the viewfinder prism. The Mode dial also has a new Movie position in between the Program and Scene positions. There's also a K-x logo screen-printed to the right of the Mode dial, and the K2000's dedicated 'Help' button has been replaced by Pentax's Green button.

Back View. Hardware-wise, the back of the K-x is almost unchanged from that of the K2000. A couple of buttons have had their functionality changed, with the Flash Up button now sharing duties as a Delete button, while the Menu and Info functions each jump one button downwards, freeing up space for a dedicated Live View button. The AF button is now an AF/AE-L button, and the screen printing moves adjacent to it. Finally, the bump in the middle of what was formerly the Delete button (now the Menu button), helping distinguish it from other buttons by touch, has been removed.

Bottom View. Finally, seen from below the K-x is completely indistinguishable from the K2000.

Operation

Pentax K-x Operation

Like the K2000 / K-m before it, operation of the Pentax K-x digital SLR is largely as straightforward as you'd expect from a consumer DSLR, although it does manage to offer a few fairly unusual features such as high-dynamic range photography and a cross-processing effect. The large Mode dial on top of the camera controls the main operating modes, and hints at one of the main changes from the K-x's predecessor. It has the usual Pentax consumer SLR options for Auto Picture, Program, Sensitivity priority, Shutter priority, Aperture priority, and Manual, plus a variety of Picture and Scene modes, but also now includes a Movie setting. See the Modes & Menus tab for details on the various exposure modes.

Several of the Pentax K-x's control buttons perform multiple functions, which saves space and time. The e-dial for example controls a variety of settings when turned in combination with a press of a button, and the arrow keys of the Four-way arrow pad access shortcuts to common camera settings as well. The Pentax K-x's LCD menu system is straightforward, with four main menus accessible via a tabbed interface at the top of the screen. Considering the multi-functional controls and variety of menu options, it will probably take most users a little time with the manual to really get the gist of things, but operation becomes intuitive after that.

LCD Monitor

The Pentax K-x's main TFT color LCD monitor is used for status display, accessing menus, image review as well as image preview in Live View mode. At 2.7-inches, the LCD panel is a little smaller than the 3-inch panels found on many SLRs these days, and resolution is a fairly ordinary 230,000 dots (approx. 320x240 RGB pixels), and also features a wide viewing angle. The LCD's brightness can be adjusted in 15 steps, and color can be adjusted in 15 steps on a 2-dimensional Green/Magenta vs. Blue/Amber color grid for a total of 225 combinations. You can adjust the color while viewing a captured image in the background, useful for matching your computer monitor. You can also adjust the display color scheme, choosing from six presets, and set the text size, selecting between "Standard" and "Large" fonts.

Status Display
When you turn on the Pentax K-x, the main LCD displays a status screen by default, showing the current record mode settings. The display can be switched off, and through the camera's Memory setup this can be made the default after power-up as well. The status screen updates in real-time while adjustments are made, and by pressing the Info button it can be replaced with an interactive Control Panel screen that allows certain settings to be changed without the need to enter the menu system. Both the Status and Control Panel displays automatically flip between landscape and portrait mode displays depending on the orientation of the camera. There's also a Guide display which appears briefly when you change exposure modes. The time it is shown can be changed, or it can be completely disabled in Setup Menu 1.

See the illustration (courtesy of Pentax) and table below for detailed information:

Control Panel Display
When the INFO button is pressed, the Status screen changes to a Control Panel display, allowing direct access to both commonly adjusted settings and some less commonly adjusted settings without the use of the menu system. The Control Panel display will disappear automatically after 30 seconds of non-use, reverting back to the Status display above (if enabled), or a blank screen. As well as pressing the OK button to select and adjust an item in its own screen, it's also possible to simply roll the e-dial while an item is highlighted, making the settings change without ever leaving the control panel display.

See the illustration below (courtesy of Pentax) for detailed callouts of the settings available in the Control Panel display.

Playback Mode Displays
In Playback mode, the default image display shows the most recently captured image, with a modest information overlay present. Pressing the Info button once pulls up the Pentax K-x's histogram view. Pressing the up or down arrow switches between a luminance histogram and an RGB+Luminance histogram set. Any overexposed areas in the frame also blink, if the option is selected in the Playback menu. Pressing the Info button again brings up a detailed information display, which decreases the image to a thumbnail on the screen. All of the same information is reported here as in the detailed display in record mode, listed above. Pressing the up or down arrow switches between this page, and one showing the photographer and copyright holder information if recorded for a particular image or movie. A third press of the Info button brings the image back fullscreen, with no information. In all display types except the RGB+Luminance histogram and the detailed information display (where the thumbnail is too small for it to be feasible), any clipped areas in the frame blink if the option is selected in the Playback menu. Under-exposed areas blink in yellow, while overexposed areas blink red.

Turning the e-dial in this mode controls the index display and image enlargement options. The index display can show 4, 9, 16, or 36 thumbnail images at a time on-screen (the default is 9; pressing the Info button allows you to select the number of thumbnails shown), while the enlargement feature magnifies images as much as 16x. There are also display-by-folder and display-by-shooting-date (calender) options. A handy "Compare Images" mode lets you display two images side-by-side, which can be enlarged to 16x as well. When viewing by shooting date, all dates for which there are images or videos are listed down the left-hand side of the screen, with blue headers for the year and month, and the days for each month grouped beneath the header listing the day of the week and date. Near the bottom right of the screen is a strip which can scroll through up to four thumbnails from the date in question, beneath a larger preview of the currently selected image.

Finally, a particularly unusual feature is that the Pentax K-x lets you examine two images side-by-side, by pressing down arrow while viewing an image or video, then selecting the Image Comparison icon. Since there's only one control dial, this mode is rather cut down from that in the company's prosumer K-7 digital SLR, which allows each image to be separately zoomed and panned to view the desired areas, after which both images can be zoomed or panned simultaneously from this preset starting point. In the K-x the comparison mode is much simpler, only allowing linked control of zoom and pan for both images simultaneously. It's perhaps a little easier to learn to use in this manner, but lacks the versatility of being able to compare the same areas of images with significantly differing zoom or composition side by side.

While in playback mode, you can of course manipulate captured images. Options available are rotation, applying digital filters, resizing, cropping, and RAW development. You can even join multiple images together into a sort of index print, using a number of templates including Thumbnail, Square, Random, and Bubble. There is also a slideshow mode available.

Optics

Pentax K-x Optics

Kit Lens. The Pentax K-x usually comes bundled with an smc PENTAX-DA 18-55mm F3.5-5.6 AL II kit lens. We tested this lens over at SLRgear.com, and found it to be quite good for a kit lens, and an improvement over the previous version. Here's a link to the SLRgear review. See below for our lens test results when used with the Pentax K-x.

Lens Compatibility. The Pentax K-x features a Pentax K_AF2 bayonet lens mount, and according to Pentax, is compatible with the company's entire series of K lenses. While not all functions will be available with every lens, particularly with older lenses without AF contacts, die-hard Pentax fans who already have a large collection of lenses will doubtless be pleased with the K-x's broad range of lens choices. (The camera's Custom menu offers a handful of options for lenses that cannot directly communicate with the camera, such as the use of the aperture ring and display of focus indicators.) The latest DA lenses with ultrasonic motors are fully supported; the only real limitation is that the Power Zoom function available on certain FA zoom lenses isn't supported on the K-x.

The table below (courtesy of Pentax USA), details the K-x's lens compatibility with the various types of Pentax lenses.

More points, improved function. The Pentax Kx uses an 11-point AF system vs the K2000's 5-points, and all 11 AF points are addressable, unlike the K2000 which offered only wide and center area modes. Compared to the prosumer K-7, the K-x lacks the AF point indication in the viewfinder, the dedicated AF assist lamp, and both the illuminant color correction and AF adjustment capabilities. (The grey focus points in the above image are not visible in the viewfinder.)

Pentax K-x Autofocus System. Compared to the K2000 / K-m, the new Pentax K-x offers an improved 11-point AF system that is based around the same SAFOX VIII+ sensor featured in the higher-end K-7 digital SLR, but with a few related hardware and firmware features dropped from the design.

The Pentax K-x doesn't include the light-color sensor which allows the K-7 to improve its autofocus accuracy under light sources with widely varying hues.

The Pentax K-x also lacks the dedicated AF assist lamp found in the K-7, relying instead on the built-in flash or the AF assist function that's found in some of the company's external flash strobes, such as the AF360FGZ and AF540FGZ. The built-in flash makes a great AF-assist light, as it is very bright, but it requires that the flash head be raised for it to work, so it isn't available for available-light photography. It's also not available in Live View contrast-detect and face-detection AF modes, as the flash duration is too short to be of much assistance during focusing, and it will also not fire in AF.C servo mode (see below).

As noted elsewhere in this review, the K-x lacks any precise indication of AF point location or selection in its viewfinder, with only a set of frame marks that indicate the outer limits of the area covered by the AF system, and an in-focus indictor in the info display area along the bottom of the viewfinder.

Unlike the K-7, the Pentax K-x's focus mode switch only offers two selections: AF (autofocus) and MF (manual focus); however the AF.S (Single) and AF.C (Continuous) servo modes offered on the K-7's AF lever are still available on the Pentax K-x, but are selected via a menu option. AF.S mode locks focus once acquired, and won't refocus unless you remove your finger from the shutter release and half-press it again. The shutter cannot be released unless the camera has acquired focus in this mode. In AF.C mode, autofocus in performed continuously while the shutter release is half-pressed, which is designed to track a moving subject. Unlike AF.S mode, the shutter can be released without acquiring focus when the shutter button is fully depressed in AF.C mode. The Pentax K-x offers a third mode not found on the K-7, called AF.A (Auto), which automatically switches between Single and Continuous mode, depending on subject motion.

The Pentax K-x offers four AF area modes: 5-area Auto, 11-area Auto, Select, and Center. This is up one mode compared to the K-7, which offers just Auto, Select, and Center. In 5-area Auto mode, the camera will select from among the five inner AF areas, arranged in a cross pattern (see animation above). In 11-area mode, it can select from among all 11 AF points. In Select mode, the user selects the specific AF point using the four-way controller and the diagram shown on the LCD. In Center mode, only the center point AF area is used. As mentioned above, there is no indication in the viewfinder of which AF area has been selected or is in focus.

Finally, the Pentax K-x lacks the ability to fine-tune both body and lenses to prevent slight issues with back- or front-focusing.

With the exception of the absence of viewfinder AF indicators, we doubt Pentax's target customers for the K-x will be perturbed by most of these differences. The lack of any way to confirm which AF point the camera has automatically selected, or to manually select AF points without removing your eye from the viewfinder is a disappointing omission. The good news is that the Pentax Kx is a little faster to autofocus than the K2000, and faster in Live View mode than even the K7. It also beats cameras like the Nikon D300S and Canon 7D in its full autofocus lag score, in good light. Pretty impressive.

The Catch-in Focus mode found on the K-7 is also supported by the K-x. This mode, which is accessed via Custom Menu 21, automatically trips the shutter once a subject comes into focus at a pre-determined focal point. AF.A or AF.S servo mode must be selected, and either a manual focus or a DA or FA lens set in MF mode must be used.

Shake Reduction. The K-x includes Pentax's body-based Shake Reduction technology. Unlike lens-based systems, the Pentax K-x's in-body stabilization functions with pretty much any lens that can be attached to the camera. Shake Reduction comes in very handy when shooting with long zooms without a tripod, as they magnify any blurring from camera shake during exposure. Shake Reduction is also useful when shooting under low lighting with a slightly slower shutter speed. According to Pentax, Shake Reduction gives you the flexibility of up to 4 stops slower shutter speed without risking blurring from camera movement; though realistically, exposures longer than 1/15 second typically turn out best with a tripod or other method of camera stabilization. Shake Reduction requires some communication from the lens, particularly the focal length setting. However, for lenses that cannot communicate with the Pentax K-x, you can set the focal length from 8 to 800mm through a setting in the Record menu.

The Shake Reduction function is enabled or disabled through the Control Panel display or page four of the Record menu, and will automatically display the Shake Reduction menu if the camera has no feedback from the lens. Note that Shake Reduction isn't recommended for tripod shooting, and will automatically disable in the self-timer modes, remote control modes, Bulb mode, HDR mode, and when using a wireless flash. It's also not recommended when using very low shutter speeds.

Unlike the system used in the Pentax K-7 (but in common with every other sensor-shift camera on the market), the K-x's shake reduction doesn't correct for rotation, only for horizontal and vertical motion. The drawbacks to sensor shift Shake Reduction technology as used by Pentax and several other companies are twofold. One is that you can't see its effects as you look through the optical viewfinder, as you can with Canon and Nikon's lens-based stabilization systems. But thanks to the Pentax K-x's Live View mode, you can indeed see the effect on the LCD, and SR seems to be pretty solid and effective. The other potential disadvantage is that sensor shift designs aren't necessarily as effective at correcting for shake on lenses with longer focal lengths, compared to lens-based stabilization. At least one third party does offer lens-based stabilization for Pentax digital SLRs, so the potential is there to simply disable the body's own shake reduction and use the lens's stabilization if available. We'll be interested to see if other third parties -- or indeed Pentax themselves -- begin to offer stabilized lenses for Pentax's KAF2 mount, something that could give Pentax users the best of both worlds: lens-based stabilization for long focal lengths, and body-based to allow stabilization with the remainder of the user's lens collection.

Dust Reduction. The K-x also includes a Pentax dust removal system, but it's the previous generation, rather than the updated DR II system that debuted in the Pentax K-7. Like past models, the K-x relies on a combination of SP coating on the low-pass filter to keep dust from adhering to the sensor, and vibration using the sensor shift mechanism to try and remove dust from the sensor. Our past testing has found this to be rather ineffective, compared to systems like that in the K-7 which instead use a piezo-ceramic element to vibrate the low-pass filter. The Pentax K-x does at least offer a Dust Alert function which makes it easy to spot dust on the sensor by taking a test shot with optimal exposure and high contrast for detecting dust visually, making it easier to find and manually remove dust particles. The mirror can be locked up for this purpose in a Sensor Cleaning mode found in page four of the Setup menu.

Despite the dust cleaning features, we haven't seen an automatic system yet that's capable of removing all dust. So while this is a nice feature to have, don't be fooled into thinking that you won't have to either learn how to clean your sensor or send the camera in for cleaning.

If you've got dust specks on your sensor (and sooner or later you will), you're going to need to clean it. There are a lot of products out there intended to address this need, but a distressing number of them work poorly (if at all), and many are grossly overpriced. Advertising hype is rampant, with bogus pseudo-scientific jargon and absurd product claims. And prices -- Did I mention prices? How about $100 for a simple synthetic-bristle brush?

So how do you know what product to use?

We don't pretend to have used everything currently on the market, but we can tell you about one solution that worked very well for us. The "Copper Hill" cleaning method is straightforward and safe, and in our routine usage here at Imaging Resource, highly effective. Better yet, the products sold by Copper Hill Imaging are very reasonably priced. Best of all, Nicholas R (proprietor of Copper Hill) has put together an amazingly detailed tutorial on sensor cleaning, free for all.

Sensor cleaning is one of the last things people think about when buying a d-SLR, but it's vital to capturing the best possible images. Take our advice and order a cleaning kit from Copper Hill right along with your d-SLR, so you'll have it close at hand when you need it: You'll be glad you did!

(While they've advertised on our sister site SLRgear.com from time to time, we receive no promotional consideration from Copper Hill for this note. We just think their sensor cleaning products are among the best on the market, and like their way of doing business. -- We think you will too. Click here to check them out.)

Distortion / Lateral Chromatic Aberration Correction. The Pentax K-x can correct for both lens distortion and lateral chromatic aberration in-camera, when using DA, DA L, and D FA lenses without any accessories between the lens and camera body. This is a feature usually found on more expensive camera models, and Distortion correction corrects both pincushion and barrel distortion for all except the DA Fish-Eye 10-17mm lens, helping ensure lines that should be straight appear so in the final image. Lateral chromatic aberration correction aims to fix color fringing and blurring which can be especially prominent with some lenses toward the corners of the image. While they're only relevant to Raw shooting if you're using Pentax's bundled Digital Camera Utility 4 software or processing the images in-camera, JPEG shooters gain the benefit of both corrections regardless of the software they're using on their computer. Both corrections slow down the camera's burst shooting capabilities significantly, though. This need only be an issue for JPEG shooters. Raw shooters can leave both effects disabled at capture-time to improve the burst speed, and then later apply them in images that require correction when developing the Raw files in-camera. See our test results below to see how well both types of lens correction work.

Pentax K-x Optical Test Results

Below are the results of our optical tests on the Pentax K-x, tested with the 18-55mm f/3.5-5.6 kit lens included in the product bundle.

Kit Lens Test Results

Zoom
Pretty good performance with the Pentax 18-55mm kit lens.

The Pentax K-x is usually sold bundled with a 18-55mm f/3.5-5.6 lens. The kit lens offers a typical optical zoom range of approximately 3x, translating to about 27-83mm when converted to 35mm equivalent. Detail and sharpness were very good across the frame full wide-angle, with low levels of coma distortion and minor softening in the corners, but some fairly strong chromatic aberration is visible in the corners. Results at full telephoto were also good, with very little corner softness and much lower levels of chromatic aberration.

Macro
An average sized macro area with the 18-55mm lens, with soft detail. Flash throttled down well up close.

Like zoom range, macro performance will depend entirely on the lens being used. With the Pentax 18-55mm lens, the K-x captured an average size minimum area, measuring 2.53 x 1.68 inches (64 x 43 millimeters). Detail was a quite soft across the frame, and even softer in the extreme corners. (Most lenses have some softening in the corners at macro distances.) The K-x's flash did a good job at throttling down for the macro shot, resulting in an even, albeit slightly dim exposure.

Geometric Distortion
About average distortion at wide-angle and at telephoto with the 18-55mm lens.

Barrel distortion at 18mm is 0.8 percent

Pincushion distortion at 55mm is 0.2 percent

The Pentax 18-55mm lens produced about 0.8 percent barrel distortion at wide-angle, which is about average and noticeable in some of its images. At the telephoto end, there was about 0.2% pincushion distortion, also about average but still noticeable in some shots. Geometric Distortion is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide-angle) or inward (like a pincushion -- usually at telephoto).

Camera JPEG, Distortion Correction Enabled

Barrel distortion at 18mm is 0.1 percent

Pincushion distortion at 55mm is almost nonexistent

The Pentax K-x does not apply any geometric distortion correction to JPEGs by default, as uncorrected RAW files have the same amounts. There is however a menu option to turn Distortion Correction on. The image above shows wide angle with Distortion Correction enabled. The Pentax K-x reduced the 0.8% barrel distortion into about 0.1% at wide angle, and reduced the pincushion distortion to less than 1 pixel at telephoto.

Chromatic Aberration and Corner Sharpness
Moderately high chromatic aberration at wide-angle, but low at telephoto with the 18-55mm lens. Soft corners on the right-hand side at wide-angle.

Chromatic Aberration. Chromatic aberration is moderately high at the full wide-angle setting of the Pentax 18-55mm lens. At telephoto, chromatic aberration is much lower and hardly noticeable. (This distortion is visible as a slight colored fringe around the objects at the edges of the field of view on the resolution target.) The Pentax K-x does not apply any chromatic aberration correction to JPEGs by default, so uncorrected RAW files have similar amounts. There is however a menu option to turn Lateral Chromatic Aberration Correction on (see below).

Corner Softness. The Pentax 18-55mm lens produced soft corners on the right-hand side of the frame at full wide-angle, though softness didn't extend far into the frame. The left side was sharper. At telephoto, corners were a little soft, with the bottom left corner being slightly softer than the rest. The center wasn't as sharp at telephoto as it was at wide-angle. These are typical results for a kit lens, considering the aperture was wide-open for these shots. (Corner sharpness and vignetting typically improve as the lens is stopped-down from maximum aperture.)

Camera JPEG, Lateral Chromatic Aberration Correction
Disabled	Enabled

As illustrated by the crops above, the Pentax K-x was reasonably effective at removing the color fringing with Lateral Chromatic Aberration Correction enabled, though it is still detectable.

The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Pentax K-x Photo Gallery .

Exposure

Pentax K-x Exposure

Metering
As with most SLRs, three metering methods are available on the Pentax K-x: Multi-segment, Center-Weighted, and Spot. All are accessed through either the Control Panel display on the LCD panel, or through page two of the Record menu. In Multi-segment mode, the camera takes an exposure reading from 16 segments and chooses the best exposure based on brightness and contrast across much of the scene. The Pentax K-x gives you the option to link the AF points to autoexposure in Multi-segment mode, via a Custom menu setting. Center-Weighted metering reads from the center of the frame, but from a fairly large area. Center-Weighted mode is automatically selected if a lens other than a DA, DA L, D FA, FA J, FA, F, or A lens is mounted, or when the lens aperture ring is set at other than "A." Spot metering simply reads the exposure from the very center of the image, so you can pinpoint the specific area of the photograph you want properly exposed. (Spot metering is very handy when you have a subject that's backlit, or that has a very different brightness, either lighter or darker, than the background.)

By default, the AF / AE Lock button triggers autofocus, but you can program it to lock the current exposure settings whenever pressed. (AE Lock is useful when you want to base your exposure on an off-center subject. Point the camera at the subject, lock the exposure, then recompose your shot however you like. Your subject will be correctly exposed, regardless of what might be in the center of the frame when you finally snap the shutter.) Through the Setup menu, you can designate the function of the AF / AE Lock button, and how it works in conjunction with the Shutter button and Autofocus system.

In situations where exposure compensation is necessary, simply press the Exposure Compensation button and turn the e-dial (in all exposure modes except Manual) and the exposure value (EV) will display in the viewfinder and on the LCDs. EV compensation ranges from -3 to +3 EV in increments of 1/3 or 1/2 EV, or you can use the Auto Exposure Bracketing function to automatically bracket an exposure in three increments of either 1/2 or 1/3 EV steps each. AEB is handy for those times when you want to make sure you get just the right exposure for a critical subject, and the order in which the shots are captured can be customized to your preference. Unless using flash exposures, Exposure bracketing works with the camera's Continuous drive mode, allowing all three frames to be captured in a burst by holding down the shutter button.

White Balance
White balance options include Auto (which ranges from about 4,000K to 8,000K), Daylight (5,200K), Shade (8,000K), Cloudy (6,000K), Fluorescent Daylight Color (6,500K), Fluorescent Daylight White (5000K), Fluorescent Cool White (4200K), Fluorescent WarmWhite (3,000K), Tungsten (2,850K), Flash (5,400K), Color Temperature Enhancement (CTE) which is used to retain and strengthen the color tone of the light source, and Manual. Pressing the AWB (left arrow) button brings up the White Balance menu. The Manual option is useful for basing the white balance on a white card. You can also adjust the white balance, controlling the amount of amber, green, blue, and magenta in the color balance using a 2D grid, in any of the selected modes. Pressing the Exposure Compensation button will capture a fresh  image with the current settings, without writing it to the flash card - although if you are pleased with the result you can then press the info button to write the image to the SD card. This ability to "tweak" the white balance, called White Balance Fine Tuning, is very helpful when dealing with difficult light sources. When using Picture or Scene modes, or the K-x's Cross Processing function, white balance cannot be adjusted.

ISO Sensitivity
The Pentax K-x lets you adjust its light sensitivity, in 1, 1/2, or 1/3 EV steps, with options ranging from 200 to 6,400 ISO equivalents. An Expanded Sensitivity Custom menu option increases this range at both ends, allowing sensitivities from ISO 100 to ISO 12,800. Sensitivities higher than ISO 3,200 are not possible when shooting exposures of 30 seconds or longer. An Auto ISO mode in which the camera selects an ISO appropriate to the subject's brightness is also provided. The Auto ISO system seems to adhere to the "1/focal-length for shutter speed" rule, meaning if the focal length is 100mm, the camera will attempt to select a shutter speed of 1/100s and choose a corresponding ISO speed. The default range for Auto ISO is, but you can set both the minimum and maximum ISO. Higher ISO settings are helpful when you want faster shutter speeds under normal lighting, to help freeze fast action.

Noise Reduction
Of course, as with all digital cameras, the higher ISO settings produce photos with more image noise, in much the same way that higher-ISO films show more film grain. To combat this problem, the K-x offers a High-ISO Noise Reduction option through the Record menu, which reduces the amount of image noise at high ISOs. Options consist of Off, Low, Medium, and High, with a default of Medium. Like Pentax's prosumer K-7 DSLR, the Pentax K-x offers the ability to select at what ISO this NR kicks in. Options are ISO 400, 800, 1,600, and 3,200. Regardless of this setting, High ISO NR is always applied to images shot at ISO 6,400 or above. A second type of Noise Reduction called Slow Shutter Speed NR subtracts a second, dark frame to remove noise and hot-pixels depending on the conditions, such as shutter speed, sensitivity, and internal temperature. Settings for that option are On (default), and Off. Regardless of this setting, Slow Shutter Speed NR is always applied on exposures longer than 30 seconds.

Expanded Dynamic Range
The Pentax K-x offers Expanded Dynamic Range options, which attempt to preserve highlights and/or shadows in high-contrast situations. Like the K-7, the K-x offers separate Highlight Correction and Shadow Correction options. Highlight Correction has On/Off settings, while Shadow Correction has three strengths (Low, Medium, and High), along with Off. When Highlight Correction is enabled, the minimum sensitivity is ISO 400 by default, or 200 if Expanded Sensitivity is set on in the first page of the Custom Setting menu.

HDR Capture
The Pentax K-x offers the same High Dynamic Range option which debuted on the K-7. As with that camera, the K-x's HDR mode captures three images in quick succession -- one underexposed, one properly exposed, and one overexposed -- and then combines them in-camera. It uses highlight detail from the underexposed image, and shadow detail from the overexposed image to produce a high dynamic range composite. There are three settings available: Off, Standard, and Strong. When enabled, the HDR mode precludes the use of Raw file format, multi exposure, cross processing, digital filters, bulb exposures, and shake reduction. Also, drive modes except single-frame shooting and remote control are disabled. Since the Pentax K-x cannot microalign images in-camera, a tripod must be used to ensure there is no movement between the three frames. Likewise, HDR capture isn't suitable for moving subjects (at least, unless you're intentionally aiming for bizarre effects). Each HDR capture requires a brief processing time to create the final image, and the three source images can't be saved -- they're discarded when processing is complete.

Multiple Exposure
The Pentax K-x's Multiple Exposure feature allows you to combine 2 to 9 images into a single image as they are being captured. If shooting in Live View mode, the previous image(s) are shown as a semi-transparent overlay on the live view image, as an aid to precise alignment of subsequent images. Pressing the Flash Up / Delete button during shooting discards the previously captured images, and starts the multi exposure anew. ISO sensitivity, shutter speed, aperture, exposure compensation, and AF point can all be adjusted between shots, and the flash can be popped up or closed to use it only on some frames. Pressing the Play, Menu, or Info buttons or powering the camera off saves the multi-exposure image (even if not all shots have been captured), as does adjusting drive mode, flash mode, white balance, custom image or digital filter. Multi-exposure mode is disabled when Cross processing, Digital filters or HDR capture are set, and when the camera is in Movie mode. Interestingly, it *is* possible to save multi-exposure images as a single Raw file, though!

An option called Auto EV Adjustment can average the exposure of each individual shot so that the combined image has the same brightness as a normally exposed individual shot. When disabled, the process is additive, just like shooting multi-exposures on film. To understand the difference, imagine a two-frame exposure where the same point is mid-grey in one image, and near-white in the other image. With auto EV adjust disabled, the same point in the final image will be completely white (clipped in every channel). With the adjustment enabled, the same area will have a brightness halfway between that of the same point in the brighter and darker images. An interesting usage of this feature is that multiple frames can be combined in-camera with averaged exposure to yield a single image with reduced noise / an effective exposure longer than would ordinarily be the case without the use of a neutral density filter.

Custom Image
The Pentax K-x offers the user the ability to apply and modify pre-existing image profiles for use on JPEG images. (Raw files are also tagged with the image parameters, but most Raw processing software other than Pentax's bundled Digital Camera Utility 4 will not obey the tags.) The camera offers seven image style settings: Bright, Natural, Portrait, Landscape, Vibrant, Muted, and Monochrome. The following image parameters can be adjusted for each profile: Saturation (-4 to +4), Hue (-4 to +4), High/Low Key (-4 to +4), Contrast (-4 to +4), Contrast Highlight (-4 to +4), Contrast Shadow (-4 to +4), and Sharpness (-4 to +4). Saturation and Hue can only be adjusted when Monochrome is not selected. When using Monochrome, instead of Saturation and Hue, B&W Filter Effects and Toning options are provided. Filter effects consist of Green, Yellow, Orange, Red, Magenta, Blue, Cyan, and Infrared Color. Monochrome can be further modified with a Toning adjustment which allows you to dial in up to four arbitrary units of either selenium style processing (blues) or sepia style processing (browns). The interface allows you to take a sample image with the preview button, or shows you the last image shot to use as a reference image. Adjustments made in the interface are simulated in the sample image. Of course, you can also select between sRGB and Adobe RGB color spaces in another menu. Cross-processed images don't allow use of the custom image settings.

Digital Filters
The Pentax K-x offers seven canned digital filter effects, plus a Custom setting that allows you to select the amount of each effect to your liking. The seven predefined filter effects are: Toy Camera, Retro, High Contrast, Extract Color, Soft, Star Burst, and Fish-eye. Parameters for each filter can be adjusted. The Custom Filter option allows you to adjust all the parameters: High Contrast (Off, +1 to +5), Soft Focus (Off, +1 to +3), Tone Break (Off, Red, Green, Blue, Yellow), Shading Type (six types), Shading Level (-3 to +3), Invert Color (On, Off), Distortion Type (three types), and Distortion Level (Off, Weak, Medium, Strong). In addition to these capture filters, the K-x offers eight more in Playback mode (Monochrome, Color, Water Color, Pastel, Slim, Miniature, HDR, and Base Parameter Adjust), and up to 20 filters can be combined in Playback mode (with any capture-time filter counting toward the twenty filter total).

Cross Processing
The Pentax K-x offers a new mode that didn't appear on its previous prosumer K-7 digital SLR, which aims to replicate a film technique known as cross-processing. For film photography, the method is to deliberately process one type of film using chemicals intended for a different type, with often surprising effects. The K-x's Cross Processing mode replicates this by adjusting the image after capture with equally unpredictable results, with no way to preview the result before capture, though you do get a rough look at which direction the camera is going to take the shot in Live view mode. It also seems to change what it's going to do, even if they scene doesn't change. Use of the cross-processing mode isn't possible while shooting Raw images, multi-exposures, or high dynamic range captures. With cross-processing enabled, access to the custom image and white balance settings is also disabled. Note that this screenshot was captured with version 1.00 firmware. Version 1.01 adds three presets, as well as being able to assign Cross Processing function to the Green button.

Drive Modes
Like most SLRs, the Pentax K-x offers a number of Drive Modes. Modes include Single Frame, Continuous Lo, Continuous Hi, Self-timer (12 seconds), Self-timer (2 seconds), Remote Control, Remote Control (3 second delay), and Exposure Bracketing. In Single-Frame mode, only one image is captured each time the shutter release button is pressed, even if it is held down. According to Pentax, "Continuous Lo" can record JPEGs (of any resolution / quality level) continuously until the card is full, at an approximate rate of 2 frames-per-second. "Continuous Hi" mode increases the burst rate to 4.7 frames per second, but with a limit of 17 JPEG frames before shooting slows down, when using the highest resolution and lowest compression. Lower-res or higher-compression modes should manage more shots in a burst. When we tested with the highest JPEG quality level, marked with three stars (***), we got 1.85 frames-per-second for over 50 frames for Continuous Lo and 4.32 frames-per-second for 25 frames for Continuous Hi. (Note that our test target is difficult to compress, so buffer lengths using typical subjects are usually better.)

The Pentax K-x also offers two Self-Timer modes for self-portraits or those occasions when you don't want to risk camera shake on a long exposure by pressing the Shutter button to trip the shutter. You can choose between a two- or 12-second countdown. The two-second countdown is useful for times when you're taking a long exposure with the camera on a tripod, and you want to minimize any camera shake from pressing the Shutter button. In this mode, the mirror is raised immediately after pressing the shutter, giving time for vibrations to dampen before the exposure starts two seconds later. The Remote Control modes offered are immediate release, or 3-second delayed release. The Pentax K-x has an IR receiver for wireless remotes, located on the front of the camera. A traditional Auto Exposure Bracketing mode is also provided, where three frames can be taken with programmable bracket value and order.

The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Pentax K-x Photo Gallery .

Not sure which camera to buy? Let your eyes be the ultimate judge! Visit our Comparometer(tm) to compare images from the Pentax K-x with those from other cameras you may be considering. The proof is in the pictures, so let your own eyes decide which you like best!

Performance

Pentax K-x Performance

Imaging

Pentax K-x Image Quality

Color

Saturation & Hue Accuracy
Bright, intense colors with moderate oversaturation of strong blues, reds, and greens.

In the diagram above, the squares show the original color, and the circles show the color that the camera captured. More saturated colors are located toward the periphery of the graph. Hue changes as you travel around the center. Thus, hue-accurate, highly saturated colors appear as lines radiating from the center.

Saturation. Like all recent Pentax DSLRs, the K-x's default settings push most colors by quite a bit, especially blues, greens, and some reds. Overall, images were very bright and punchy, with color that was a little over the top for an SLR, though the K-x's target market would likely prefer that to more accurate saturation. You can, however, always select a different Image Tone setting or tweak saturation and contrast to suit your own tastes. Most consumer digital cameras produce color that's more highly saturated (more intense) than found in the original subjects. This is simply because most people like their color a bit brighter than life.

Skin tones. Caucasian skin tones from the K-x lean toward the warm side, but many consumers prefer the "healthier" appearance of warmer skin tones. Where oversaturation is most problematic is on Caucasian skin tones, as it's very easy for these "memory colors" to be seen as too bright, too pink, too yellow, etc.

Hue. The Pentax K-x showed a number of color shifts relative to the correct mathematical translation of colors in its subjects, but had acceptable accuracy overall. Most noticeable was a shift in orange toward yellow, yellow toward green, with some shifts in cyans, blues, and reds as well. Hue is "what color" the color is.

Saturation Adjustment
The Pentax K-x has a total of nine saturation settings available, four above and four below the default saturation. This covers a pretty wide range of saturation levels, about as wide a range as you're likely to find photographically relevant, apart from special effects that are arguably better achieved in software. The fine steps between settings mean you can program the camera to just the level of saturation you prefer. The saturation adjustment also has almost no impact on contrast. That's how it should work, but we've often found interactions between saturation and contrast (and vice versa) on the cameras we test.

Saturation Adjustment Examples
-4	-2	0	+2	+4

The table above shows results with several saturation settings. Click on any thumbnail above to see the full-sized image.

Sensor

Exposure and White Balance

Indoors, incandescent lighting
Warm results with default Auto, slightly cool with Incandescent, though good color with Manual white balance setting. Average exposure compensation required.

Indoors, under normal incandescent lighting, color balance was quite warm with the default Auto white balance setting, with a fairly strong orange cast; however, this is considerably better than Pentax SLRs used to produce which was a bright yellow/orange cast. Like the K-7, Pentax K-x features an "Automatic White Balance in Tungsten" setting in Custom menu 9. Options are "Subtle" and "Strong" correction, with the default being Subtle. The Strong setting resulted in a reduced orange cast compared to Subtle, with a slightly magenta tint. Results with the Incandescent setting were a bit on the cool side, with a slightly bluish cast. The Manual setting was the most neutral and accurate. Note that there is also a Color Temperature Enhancement (CTE) white balance mode, which strongly intensified the orange/yellow cast in our indoor test shot. The Pentax K-x required an average amount of positive exposure compensation for our indoor scene, at +0.3 EV. Overall color with the Manual white balance setting looks quite good, though the blue flowers appear slightly purple. (Many digital cameras reproduce these flowers with a dark, purplish tint, so the Pentax K-x actually performs a little better than average here.) Our test lighting for this shot is a mixture of 60 and 100 watt household incandescent bulbs, a pretty yellow light source (2,600 Kelvin), but a very common one in typical home settings here in the U.S.

Outdoors, daylight
Bright colors overall, though a tendency toward a warm cast and slightly high contrast under harsh lighting.

Outdoors, the Pentax K-x performed fairly well, requiring about average exposure compensation of +0.7 EV for our "sunlit" portrait shot to keep the face reasonably bright. Contrast is a little high, as you might expect under such harsh lighting, and highlights in the model's shirt and flowers are clipped, but there's plenty of detail in the deep shadows. Hardly any highlights were blown out in the House shot, and shadows were pretty good, too. Color balance is good as well, if a bit warm, though default saturation is a little high. Overall, very good performance here.

See full set of test images with explanations
See thumbnails of all test and gallery images

Resolution
High resolution, 1,600 ~ 1,700 lines of strong detail.

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,700 lines per picture height in the horizontal direction, and about 1,600 in the vertical direction. Extinction didn't occur until around 2,400 to 2,600 lines. We weren't able to do much better with Adobe Camera RAW processed RAW files, though results were crisper. There were quite a few moire interference patterns near or above the resolution limit in both the camera JPEG and ACR converted RAW file, indicating a fairly weak anti-alias (AA) filter (see other areas of the resolution target). Use these numbers to compare with other cameras of similar resolution, or use them to see just what higher resolution can mean in terms of potential detail.

See full set of test images with explanations
See thumbnails of all test and gallery images

Sharpness & Detail
Sharp images overall, though visible edge-enhancement on high-contrast subjects. Minimal noise suppression visible.

Sharpness. The Pentax K-x produced sharp images with good detail. Some edge enhancement artifacts in the form of "halos" are visible on high-contrast subjects such as the crop above left, but overall results are still pretty good. Edge enhancement creates the illusion of sharpness by enhancing colors and tones right at the edge of a rapid transition in color or tone.

Detail. The crop above right shows only minimal noise suppression, as the darker areas of the model's hair show a lot of detail. Individual strands are still distinguishable even in the lighter shadows, though they begin to merge as shadows deepens. Still, a great performance, as many SLRs have quite a bit more trouble with the straight, red strands of hair here. Noise-suppression systems in digital cameras tend to flatten-out detail in areas of subtle contrast. The effects can often be seen in shots of human hair, where the individual strands are lost and an almost "watercolor" look appears.

RAW vs In-Camera JPEGs
As noted above, the Pentax K-x delivers sharp images, but with some visible sharpening artifacts in camera JPEGs. (At least in this shot - the camera appears to adapt sharpening depending on the image structure.) More detail can be obtained from carefully processing RAW files, though, while at the same time reducing sharpening artifacts. Take a look below, to see what we mean:

Camera JPEG (Fine)	RAW via ACR

In the table above, mousing over a link at the bottom will load the corresponding crop in the area above. Examples include in-camera Fine (***) JPEG, and RAW (.DNG) file processed through Adobe Camera Raw version 5.6b, then sharpened in Photoshop. For the Pentax K-x's images, I found best results with strong but tight 300% unsharp masking with an 0.3 pixel radius. As you can see, the JPEG has quite a bit more contrast, but the ACR conversion contains more detail than the JPEG, and there are fewer sharpening artifacts as well. We should mention that in addition to 9 sharpening levels, the K-x has a "Fine Sharpening" option, however we didn't test those settings.

ISO & Noise Performance
Low noise at the normal sensitivity settings, with excellent results up to ISO 400, and surprisingly good results up to ISO 1,600. 

Noise Reduction = Medium, Start = ISO800 (Default Settings)
ISO 100	ISO 200	ISO 400
ISO 800	ISO 1,600	ISO 3,200
ISO 6,400	ISO 12,800

The Pentax K-x produced low noise at its lower sensitivity settings, and even at ISO 400, noise is fairly low, with little detail lost to the noise reduction. (The K-x's default noise reduction doesn't kick in until ISO 800.) At ISO 800, noise pixels are slightly less evident than at 400, though there's a small amount of smudging visible, due to noise reduction. Still, the K-x performs better than average for its class, as there is still a lot of fine detail left. ISO 1,600 shows a bit more blurring from stronger noise reduction, but detail is still pretty good for a high ISO. ISO 3,200 isn't bad either, though there is a more noticeable drop in fine detail, and there are some greenish chroma noise blotches visible in shadow areas and in the hair. At the highest ISO settings of 6,400 and 12,800, noise levels are much higher, with heavy blurring and chroma noise blotches. We also noticed some moire interference patterns in the green jacket, at lower ISOs. Still, much better than average performance here for an APS-C sensor. Pentax has done a good job at keeping both luminance and chrominance noise low while holding on to a lot of fine detail.

The Pentax K-x offers four levels of high ISO noise reduction (Off, Low, Medium and High), as well as a programmable start ISO (400, 800, 1,600 and 3,200). That's much more flexibility in noise reduction options than a typical entry-level SLR offers. See the Print Quality section below for recommended maximum print sizes at each ISO.

A note about focus for this shot: We shoot this image at f/4, using one of three very sharp reference lenses (70mm Sigma f/2.8 macro for most cameras, 60mm f/2.8 Nikkor macro for Nikon bodies without a drive motor, and Olympus Zuiko 50mm f/2.0 for Four Thirds and Micro Four Thirds bodies). To insure that the hair detail we use for making critical judgements about camera noise processing and detail rendering is in sharp focus at the relatively wide aperture we're shooting at, the focus target at the center of the scene is on a movable stand. This lets us compensate for front- or back-focus by different camera bodies, even those that lack micro-focus adjustments. This does mean, though, that the focus target itself may appear soft or slightly out of focus for bodies that front- or back-focused with the reference lens. If you click to view the full-size image for one of these shots and notice that the focus target is fuzzy, you don't need to email and tell us about it; we already know it. :-) The focus target position will simply have been adjusted to insure that the rest of the scene is focused properly.

Extremes: Sunlit and low light tests
High resolution with strong overall detail, but slightly high contrast with strong highlights. Good low-light performance, capable of capturing bright images under average city street lighting and much darker conditions, but AF struggled at lower light levels.

Sunlight. The Pentax K-x produced slightly high contrast with some washed-out highlights and deep shadows under the harsh lighting of the test above. (The camera's default Image Tone setting is "Bright", which uses +1 out of a range of -4 to +4 for Contrast.) Shadow detail is pretty good, though, despite some minor image noise. Our outdoor target required +0.7 EV exposure compensation for a reasonably bright face, which is average for this shot. Some may prefer the +1.0 EV exposure, but we thought too many highlights were blown, and the skin tone was washed out in some places.

Because digital cameras are more like slide film than negative film (in that they tend to have a more limited tonal range), we test them in the harshest situations to see how they handle scenes with bright highlights and dark shadows, as well as what kind of sensitivity they have in low light. The shot above is designed to mimic the very harsh, contrasty effect of direct noonday sunlight, a very tough challenge for most digital cameras. (You can read details of this test here. In actual shooting conditions, be sure to use fill flash in situations like the one shown here; it's better to shoot in open shade whenever possible.)

Contrast Adjustment
We really like it when a camera gives us the ability to adjust contrast and saturation to our liking. It's even better when those adjustments cover a useful range, in steps small enough to allow for precise tweaks. Just as with its saturation adjustment, the Pentax K-x's contrast setting meets both challenges, though it could have used slightly more range on the minus side. We did, however, notice that saturation takes a hit when contrast is turned down.

Minimum Contrast
Contrast set to lowest, +0.7 EV	Contrast set to lowest, Auto Exposure

At its lowest contrast setting, the Pentax K-x did an okay job of preserving highlight detail, maintaining fairly natural-looking skin tones, and holding nice detail in the shadows. There are still blown highlights, but a bit fewer than at default contrast. The Pentax K-x captures natural looking color outdoors, though just slightly on the warm side. Overall, good results here, especially when the contrast setting is tweaked, though colors are a bit flat because of the reduced saturation.

Contrast Adjustment Examples
-4	-2	0	+2	+4

The series of shots above shows results with several different contrast adjustment settings, showing every other step, as well as the default and both extremes. While you can see the extremes, it's hard to really evaluate contrast on small thumbnails like these, click on any thumbnail to go to the full-size image. The Pentax K-x's contrast adjustment worked well, however it had quite an effect on color saturation. Contrast and saturation are actually fairly closely coupled, so this is unfortunately not unusual.

D-Range Settings
The Pentax K-x offers three Shadow Correction levels (Low, Medium, and High) as well as one Highlight Correction setting (On/Off). As the name implies, Shadow Correction works to raise shadow detail while attempting to keep highlights and midtones as they are, and likewise, Highlight Correction attempts to reduce highlights without darkening shadows and midtones. See the images and crops below to see their effect on our high contrast "Sunlit" Portrait test shot.

D-Range Examples Shadow Correction
Shadow Correction Off	Shadow Correction Low	Shadow Correction Medium	Shadow Correction High
Shadow Detail
Highlight Detail

Above, we see a gradual lightening of shadows as the Shadow Correction setting is increased, while highlight clipping remains roughly the same. If you look closely at the shadow detail, you will notice noise is more visible as the setting is turned higher, but not as much as you might think.

D-Range Examples Highlight Correction
Highlight Correction Off	Highlight Correction On
Highlight Detail
Shadow Detail

In the crops above, we can see nearly all highlight detail is preserved with Highlight Correction On (right) than it is with it Off (left), while shadow levels are virtually untouched (perhaps just slightly boosted when On). Note that we used the base ISO of 200 for our "Sunlit" Portrait shots. If we had used the ISO 100 extension, we would probably see more of a difference in noise with Highlight Correction enabled. Still, an impressive performance here.

HDR Capture
The Pentax K-x has a High Dynamic Range (HDR) capture mode where the camera takes three images (underexposed, normal, and overexposed) in quick succession and combines them in-camera into one image.  If performed properly, this method should result in much higher dynamic range, without the additional noise penalty that often comes with boosting shadows. (In fact, it can reduce shadow noise by combining shadows from the overexposed shot.) There are three HDR settings available: Off (default), Standard and Strong.

High Dynamic Range Mode
Off +0.7 EV	Standard +0.7 EV	Strong +0.7 EV

As you can see from the above images, it didn't work very well for our "Sunlit" Portrait shot, resulting in very flat and unnatural looking images with reduced saturation. It did a good job of bringing out shadow detail, but even the lowest "Standard" setting was too strong for the highlights, turning white into grey. The Pentax K-x's HDR mode may work better with a different subject such as a landscape with a bright (normally washed-out) sky. It probably isn't designed to work with portraits anyway, as subject motion would likely be a problem.

Face Detection
The Pentax K-x has a face-detection AF/AE option in Live View mode.

Face Detection
Off 0.0 EV	On 0.0 EV

As you can see above, it does improve the exposure over the default without using any exposure compensation, but the model's face is still a bit dim.

	1 fc 11 lux	1/2 fc 5.5 lux	1/4 fc 2.7 lux	1/8 fc 1.3 lux	1/16 fc 0.67 lux	1/16fc No NR
ISO 100	2 sec f2.8	4 sec f2.8	8 sec f2.8	15 sec f2.8	30 sec f2.8	30 sec f2.8
ISO 200	1 sec f2.8	2 sec f2.8	4 sec f2.8	8 sec f2.8	15 sec f2.8	15 sec f2.8
ISO 400	0.5 sec f2.8	1 sec f2.8	2 sec f2.8	4 sec f2.8	8 sec f2.8	8 sec f2.8
ISO 800	1/4 sec f2.8	0.5 sec f2.8	1 sec f2.8	2 sec f2.8	4 sec f2.8	4 sec f2.8
ISO 1600	1/8 sec f2.8	1/4 sec f2.8	0.5 sec f2.8	1 sec f2.8	2 sec f2.8	2 sec f2.8
ISO 3200	1/15 sec f2.8	1/8 sec f2.8	1/4 sec f2.8	0.5 sec f2.8	1 sec f2.8	1 sec f2.8
ISO 6400	1/30 sec f2.8	1/15 sec f2.8	1/8 sec f2.8	1/4 sec f2.8	0.5 sec f2.8	0.5 sec f2.8
ISO 12800	1/60 sec f2.8	1/30 sec f2.8	1/15 sec f2.8	1/8 sec f2.8	1/4 sec f2.8	1/4 sec f2.8

Low light. The Pentax K-x performed reasonably well on the low-light test, capturing usable images at the lowest light level with the lowest sensitivity setting (ISO 100). Low light exposure metering wasn't very reliable though, forcing us to use manual exposure mode. Noise was quite low up to ISO 1,600, but became more of an issue from there. Still, very good for a sub-frame SLR. There were a few hot pixels here and there, but nothing to be concerned about. (The K-x has a built-in pixel mapping function, so you should be able to map out any hot or dead pixels without sending the camera in for service.) There are hints of horizontal banding, but only at the highest ISOs, and it's not really that noticeable. Color balance was quite warm Auto white balance setting, though, showing a reddish cast at most light levels.

The camera's phase-detect autofocus system was only able to focus on the subject down to between 1/2 and 1/4 foot-candle light level unassisted with our reference Sigma f/2.8 lens. This is below average for an SLR, but the K-x was able to focus in complete darkness with the help of the AF assist from the built-in flash. Surprisingly, the Pentax K-x was able to focus in dimmer light when using the slower Pentax 18-55m f/3.5-5.6 AL II lens, down to between 1/4 and 1/8 foot-candle. This is still a bit below after for an SLR, but the K-x spent less time hunting for focus with the Pentax lens, so it found focus before giving up like it did with the Sigma f/2.8 prime.

In Live View mode, the camera was also able to focus down to between 1/4 and 1/8 foot-candle in both phase-detect and contrast-detect modes. When using phase-detect AF, it was able to focus in complete darkness with AF assist. AF assist is however not supported for contrast-detect mode, as autofocusing in that mode is too slow for the flash to assist effectively. Keep in mind that the longer shutter speeds here demand the use of a tripod to prevent any blurring from camera movement, Pentax's Anti-Shake not withstanding. (A useful trick is to just prop the camera on a convenient surface, and use its self-timer to release the shutter. This avoids any jiggling from your finger pressing the shutter button, and can work quite well when you don't have a tripod handy.)

How bright is this? The one foot-candle light level that this test begins at roughly corresponds to the brightness of typical city street-lighting at night. Cameras performing well at that level should be able to snap good-looking photos of street-lit scenes.

NOTE: This low light test is conducted with a stationary subject, and the camera mounted on a sturdy tripod. Most digital cameras will fail miserably when faced with a moving subject in dim lighting. (For example, a child's ballet recital or a holiday pageant in a gymnasium.) Digital SLRs like the Pentax K-x do much better than point & shoots, but you still shouldn't expect a quick autofocus lock with moving subjects.

Output Quality

Print Quality
Great print quality, good color, sharp 13 x 19-inch prints.

The Pentax K-x's printed output is really impressive, able to output usable 20 x 30-inch prints at ISO 100, straight from the camera with standard noise suppression on. They're slightly soft in some places, tack sharp in others; a little sharpening in a program like Photoshop could make them even better. 16 x 20 images are about the same, with a little more sharpness than the 20 x 30-inch prints. The amazing part is that print quality remains this good up to ISO 800! Even our troublesome red swatch still looks better than most cameras do at ISO 800, even when printed at 16 x 20.

ISO 1,600 represents the first break from this remarkable print size, and it's also the first time the red fabric swatch begins to decay. Still, the rest of the detail looks fabulous, with just a little noise and noise suppression artifacts creeping in. Reduction to 13x19 at this size is a little better.

ISO 3,200 shots also look decent printed at 13x19 inches.

ISO 6,400 shots are generally usable at 11x14, remarkably, but of course better at 8x10.

Depending on the subject ISO 12,800 shots are usable at 8x10, though contrast is increased and there's some blotchy noise in the shadows. At 5x7 inches, though, no one will notice.

A truly excellent and surprising outcome from the Pentax Kx!

Testing hundreds of digital cameras, we've found that you can only tell just so much about a camera's image quality by viewing its images on-screen. Ultimately, there's no substitute for printing a lot of images and examining them closely. For this reason, we now routinely print sample images from the cameras we test on our Canon Pro9000 Mark II studio printer, and on the Canon Pixma MP610 here in the office. (See the Canon Pixma Pro9000 Mark II review for details on that model.)

Viewfinder

Pentax K-x Viewfinder

The Pentax Kx's viewfinder is an optical, eye-level through-the-lens type, with the LCD monitor also able to display an image preview, in Live View mode.

Pentax says the K-x's optical viewfinder provides a coverage of about 96% and a magnification of approximately 0.85x. The K-x's dioptric correction adjustment (for eyeglass wearers) has a range from -2.5 to +1.5 diopter. The eyepoint is unspecified. Like basically every camera in its class, the Pentax K-x's viewfinder is a pentamirror design, which is less costly, but also less bright than pentaprism implementations. The focusing screen is not listed as being interchangeable, but it definitely is. We're a little surprised that Pentax doesn't make a big deal out of this, as it gives them another accessory to sell, and helps the Kx stand out from other entry-level DSLRs. From what we can tell, the Kx uses the same focusing screens as the K2000/K100D/K200D/K10D/K20D.

The Pentax K-x's viewfinder readouts mostly do a good job of communicating camera status and exposure settings, showing most of the usual info such as flash status, focus mode, shutter speed, aperture, focus confirmation, ISO sensitivity, EV compensation, anti-shake status, etc. One important indication is, sadly, absent however. While the K-x does show frames indicating the outside limits of the area covered by its autofocus points, it doesn't show their individual locations, nor does it offer any indication as to which point has been automatically or manually selected. Manual point selection is indicated on the LCD display, requiring the user to look away from the viewfinder while selecting AF points. In this respect, the K-x is identical to its predecessor the K2000 / K-m, which also lacked AF point indication. It's likely that a little cost was saved by excluding this feature from the design, but we have to wonder if it's a bit of a false economy. Pentax may be turning away potential users who might otherwise consider the camera, by lacking a feature that's pretty common in other consumer DSLRs (and pretty much essential in every prosumer or professional model). With that gentle rant over, see the diagram below (courtesy of Pentax) for the complete list of viewfinder indications.

Viewfinder Test Results

Coverage
Good accuracy from the optical viewfinder, very good from the LCD.

The Pentax K-x's optical viewfinder showed just over 95 percent coverage accuracy with our Sigma 70mm f/2.8 prime lens. There was also a slight shift in the image compared to the sensor. The LCD monitor showed just over 98 percent coverage in Live View mode, with no detectable shift. This is good performance for a consumer model, but just below Pentax's specification of 96 and 100 percent coverage respectively.

Live View

Video

Pentax Kx Video Recording

The Pentax K-x is the company's second DSLR to feature the ability to capture video clips, after the prosumer K-7. Much like live view capability that preceded it, video capture is rapidly becoming a must-have feature in the DSLR market. The K-x's video mode shares much in common with that of the K-7, but with some of the more uncommon features absent.

Pentax K-x Video: Image Size, Frame Rate, and Encoding

The Pentax Kx records video at either high definition 1,280 x 720 resolution with a 16:9 aspect ratio, or standard definition 640 x 416 pixels with a 3:2 aspect ratio. Both video modes record at 24 frames per second; well-suited for broadcast television, but slightly less smooth than the 30 fps video offered by some DSLRs.

New video capability. The Pentax K-x offers two resolution levels for video recording, both at 24fps with monaural sound.

The Pentax Kx records its movies as motion-JPEG (AVI) files, rather than the AVCHD format favored by some manufacturers. AVCHD is more conservative of memory card space, but at the cost of some loss of image quality when a lot of the image changes from one frame to the next, as is the case when panning or in closely-cropped video of a rapidly-moving subject. AVCHD is a subset of the broader H.264 video compression spec, one that places fairly heavy constraints on the recorded bitrate (hence its smaller file sizes). Cameras with sufficient processing power can use H.264 encoding at higher bitrates to avoid some of the limitations of AVCHD, but this comes with the requirement of greater processing power, for both recording and playback.

As noted, the Pentax K-x's video suffers no compression-related quality loss during panning, but the consequence is very large file sizes: A minute of HD video can very easily produce a several hundred megabyte file, depending on subject matter.

Recording is only part of the story, though: Editing and playback are the other aspects to be considered. When it comes to editing, the Pentax Kx's AVI format is much easier to deal with than H.264-encoded video (including AVCHD), at least currently: The more sophisticated encoding used in the H.264 standard requires quite a bit of processor power to pull it apart and put it back together again, so frame-accurate editing of H.264 requires a fast processor and capable editing program.

When it comes to playback, it's perhaps a bit of a toss-up between the two formats: AVI plays back much better on computers with relatively modest processors, while AVCHD files can be read directly by some television sets. Sadly, the Pentax K-x lacks any form of high-definition video output connectivity, so viewing videos on your TV in high-def requires either a suitable third-party device from which to play the video, or that the display itself include an SD/SDHC card slot and high-def Motion JPEG compatibility.

Here's a list showing what to expect for file sizes with the Pentax K-x's video recording:

At both resolutions, the medium and low quality settings produced almost identical file sizes. With all frame sizes, we felt that recording at anything less than the highest quality setting produced too many JPEG artifacts for our tastes: Smaller file sizes are good, but only if they provide the image quality we're looking for.

Here are some examples of video from the Pentax K-x, showing typical results under daylight conditions.

Pentax K-x Video Samples
0.9M Best Quality: 1,280 x 720, 24fps (30.3 MB)	0.3M Best Quality: 640 x 416, 24fps (14.9 MB)
0.9M Better Quality: 1,280 x 720, 24fps (26.6 MB)	0.3M Better Quality: 640 x 416, 24fps (8.2 MB)
0.9M Good Quality: 1,280 x 720, 24fps (28.5 MB)	0.3M Good Quality: 640 x 416, 24fps (6.1 MB)

Pentax K-x Video-Mode Focusing

Focusing in movie mode with the Pentax K-x is much the same as it is with most other video-capable DSLRs: You can trigger a contrast-detect AF cycle prior to the beginning of a recording by hitting the AF button on the camera's rear panel, but there's no autofocus during recording. You can manually focus the lens during a recording, though, and the true manual operation of AF on Pentax's lenses means you can do this more or less silently, simply by being careful about turning the focus ring. (We recently tested the Olympus E-P1, which uses "fly by wire" focusing, whereby the focus ring only instructs the camera to move the lens elements rather than moving them directly via a mechanical coupling. This meant that small clicks could be heard on the audio track every time the E-P1 changed the focus setting, regardless of how slowly we turned the focus ring. With true manual operation of its lenses, the Pentax K-x doesn't have this problem.) As is the case in Live View mode, pressing the Info button on the camera's rear panel lets you zoom in up to 6x when autofocusing, or 10x when focusing manually. This is helpful for confirming precise focus, but note that it is only possible before recording has started: Once the camera has begun recording, only the normal 1:1 view is available.

The omission of autofocusing capability during movie recording in the K-x likely comes down to a combination of two factors. Firstly, noise from the focusing motors would be picked up by the camera's internal microphone, although the degree to which this would be a problem would vary depending on the lens type in use. Secondly, the manner in which contrast detection autofocusing functions could also prove objectionable -- it's rather slow, and "hunts" around the point of focus. The K-x is far from alone among DSLRs in failing to offer AF function during video capture, but we must admit we'd prefer manufacturers let users make the choice as to whether or not they're willing to accept these potential drawbacks in their videos. Of course, manual focusing is still possible, but for most consumers, manual focusing during video capture is a skill they're not likely to master -- and nor would they want to do so.

As we've noted in other SLR reviews, the good news with focusing for video is that you can get surprisingly good depth of field in video mode by stopping the lens down, thanks to the relatively low resolution of the video image. With a pixel resolution of only 0.9 megapixels in the Pentax K-x's high-definition mode or 0.3 megapixels in its standard-definition mode, images that would be unacceptably blurred as 12 megapixel still shots look perfectly fine as video frames. This not only provides greater depth of field at any given aperture, but is also more forgiving of diffraction limiting at very small lens apertures. Diffraction at small apertures means you'd usually want to avoid f/16 or f/22 for still images, but again, the results generally look perfectly fine at video resolutions. Bottom line, with the K-x's lens set to f/16 or f/22 (assuming you're shooting under fairly bright conditions), you'll be surprised by how little focus adjustment is needed during a typical video recording.

Pentax K-x Video Exposure Control

In common with most other video-capable SLRs, the Pentax K-x offers the full range of white balance settings in movie mode, including four different options for fluorescent lighting, and Kelvin values ranging from 2,500 to 10,000. You can also select any of the K-x's Custom Image modes, including Bright, Natural, Default, Portrait, Landscape, Vibrant, Muted, and Monochrome. As with still-image shooting, settings for saturation, hue, high/low key adjustment and contrast can be adjusted independently for each mode. A sharpness setting is available as well, which we were slightly surprised to find actually did affect the sharpness of the video images, to a very noticeable degree. (Note that turning the sharpness up too high will make the compression artifacts much more evident, though.)

One movie-mode exposure parameter that the Pentax K-x unfortunately doesn't let you control is its shutter speed. The shutter speed appears to be tied to its frame rate, and regardless of the light level involved, rapid motion is always blurred to about the level you'd expect with a 1/24 second exposure time. (As noted above, the video frame rate of the K-x is 24fps in all resolution modes.) Shutter speed control is pretty rare in video-capable interchangeable-lens cameras; as of this writing, only a handful of models offer this feature.

Pentax Kx Video: Image Stabilization

The Pentax K-x's body-based image stabilization can be used when recording movies. Not only does this make any lens you're recording with into an IS model, but we found that the image stabilization worked exceptionally well when recording videos. Because the Pentax K-x's IS system provides such a high degree of stabilization, there's a bit of a "floating" feeling when recording videos with IS enabled: As you move and pan the camera, the video image tends to lag a little behind your motions, "catching up" when you come to a rest. A related IS effect is that the subject can drift up or down or from side to side slightly during recording. This can be slightly disconcerting, but the upside is that your videos will be much more stable than otherwise, even holding the camera at arm's length, or when shooting with a long telephoto lens.

Pentax K-x Video: Audio recording

Like most competing SLRs with video recording capability, the Pentax Kx sports only an internal, monaural microphone that can record an audio track, with no provision for an external microphone. Internal mics are somewhat problematic, in that they're prone to picking up noise produced by moving your hands on the camera or actuating any controls while recording.

In the case of the Pentax K-x, the issue can be exacerbated if you choose to use the body-based image stabilization system during movie recording If the K-x is jostled a good bit during recording with IS enabled you can hear the IS in the audio track, but not when it's being held relatively steadily: The light clacking sound that's picked up on the audio track in the face of significant camera movement seems to be the result of the sensor unit bumping up against its stops. If the camera is held even reasonably carefully, we were hard-pressed to hear any IS-related noise at all, even in a quiet office environment. In normal usage, you thus shouldn't hear any noise from the IS system, unless you're panning quite a bit, or if unstable footing results in a lot of camera movement.

We found that the Pentax K-x's built-in mic picks up up ambient sound pretty well, with sound quality and sensitivity both being good. The design seemed to be omnidirectional, picking up noise from nearby subjects behind the camera almost as well as it does those in front. It also seemed to be less sensitive to sounds picked up from focus adjustment or hand movement on the body than some other cameras we've tested.

Pentax K-x Movie Recording User Interface

The Pentax K-x's movie mode is accessed via a separate position on the camera's mode dial, rather than being initiated from within still-picture Live View mode. There's no separate control button to start/stop movie recording: Pressing the shutter button begins recording, pressing it again stops it. Some SLRs have a dedicated button to start/stop movie recording, but we find the K-x's use of the shutter button more intuitive - important, for a camera that's aimed at less experienced photographers. Without a dedicated button, the decision to promote the movie mode to its own position on the mode dial makes sense

Like the K-7 before it, the K-x groups setting adjustments for its movie mode in a sub-menu accessed via the Movie option on screen 3 of the Record Menu. We still found this a little awkward when making frequent adjustments to video settings, as the extra level of menu selection meant more button-pressing to make the changes than would have been required if they'd been available from the main shooting screen via a "quick menu," as some cameras have. That said, the more commonly accessed options for white balance and Custom Image settings were easily accessible via the 4-way control buttons on the camera's back panel.

The Pentax K-x's Record Menu options for video recording are:

Rolling Shutter Artifacts

Essentially every video capable DSLR currently on the market exhibits motion-related distortions called rolling shutter artifacts. These are caused because the image data is captured and then read off the chip sequentially by rows, rather being captured all at once. In the case of the Pentax K-x, with its 24fps frame rate, this means that image data for the last row of a given frame is captured and read out up to 1/24 second after the data for the top row was captured. The effect on moving objects is similar to that of a focal plane shutter in an SLR, but more pronounced, because the video frame is read out much more slowly than the slit of a focal plane shutter moves across the sensor.

For a camera that scans video frames vertically (as all do that we're aware of), rolling shutter artifacts will be most noticeable for subjects that are moving rapidly side to side, or when the camera itself is being panned horizontally. Verticals in the scene will appear tilted to the right or left, depending on the direction of camera motion. As an example, consider the case of a camera being panned from left to right, with a flagpole or other vertical object in the middle of the scene when recording for a particular frame begins: If the top of the object was centered horizontally when the first line of the video frame is acquired, by the time the last line of the frame has been captured, the bottom of the object will have shifted to somewhere left of center: As a result, the vertical object would appear to be leaning to the right.

The shots below show some screen grabs from our evaluation of the Pentax K-x's rolling shutter behavior.

Pentax K-x Video - Rolling Shutter Artifact
Reference: Static frame	Rolling Shutter, 0.3M resolution

The upside for the K-x relative to rolling shutter artifacts is its excellent IS system. While you can avoid the worst effects of a rolling shutter by panning slowly, even minor jiggling of the camera due to hand-holding can produce a jelly-like appearance in the video output from some models. The K-x's IS system stabilized the video well enough that we experienced no such effects when the camera wasn't being panned, so long as the scene didn't contain fast-moving subjects. If our shooting required both stationary shots and rapid panning in the same segment, though, we had to shoot with the IS system disabled to avoid clacking noise in the audio track from the internal mic.
(Unfortunately, if your shooting for any given segment will involve both panning and steady camera positions, you'll generally need to shoot with the IS system disabled, to avoid clacking on the audio track and somewhat erratic framing in response to rapid camera movements.)

Computer Requirements for Viewing HD Video

A typical computer these days has little trouble dealing with still images, but high-definition video can be another matter. Depending on the file format involved, it can take a pretty beefy computer to handle HD-resolution video playback without stuttering or dropping frames. The Motion JPEG image compression used by the Pentax K-x is one of the less compute-intensive formats, though, and its 1,280 x 720 resolution means there's a good bit less data to deal with in each frame than in videos with 1,920 x 1,080 (1080i) resolution. The net result is that you should have no problem playing video files from the K-x on your computer, as long as it's a relatively recent and reasonably powerful model. We don't have a specific benchmark for this, but if your computer is less than 3 years or so old, it should have no problem with the K-x's video streams. (By contrast, to play AVCHD or other keyframe-encoded video formats at full 1,920 x 1,080 resolution can demand a very powerful CPU and video card, to keep up.)

That said, the Pentax K-x's video codec doesn't appear to be terribly efficient, as it produces very large file sizes at its best quality setting. (And as noted earlier, its lower quality settings introduce an unacceptable level of JPEG artifacts into the image stream, so you'll want to use the highest quality setting almost exclusively.) So, while you might be able to play its videos on an older computer, you'll almost certainly need to increase your hard drive capacity. With video files occupying 300 MB/minute, it's a good thing that terabyte hard drives are so cheap these days. (At that pace, a terabyte hard drive could hold around 50 hours of video footage. That's a lot of footage if you primarily use the K-x for casual "video snapshots," but if you're a serious video user, it can still go by pretty quickly.)

Pentax K-x Video Mode: The Bottom Line

Overall, the Pentax K-x's video mode is a mixture of strengths and weaknesses. On the positive side, the K-x's video imagery was noticeably more crisp-looking than that of most SLRs we've tested to date. Its rolling shutter artifacts were a bit more obtrusive than those of 30fps video modes in some competing models, but less problematic than those seen in cameras shooting at only 20 frames/second. We found the K-x's body-based IS provided excellent stabilization during video recording, with very little impact on the audio recorded by the in-body microphone, but the strong IS also produced a "floating" feeling in videos, and sometimes made it hard to keep the subject completely stationary within the frame. Unlike the K-7, the K-x has no audio input jack, so you can't easily mitigate focusing noises or isolate sound to just a single microphone.

Video in SLRs is still somewhat at the bleeding edge of technology, so no camera we've seen (yet) does it perfectly. For the average user, though, the K-x's video is certainly good enough to avoid having to lug along a digicam on trips, just for the sake of capturing video snapshots. Recording in its highest quality setting at 720p resolution, its output will be acceptable for many more serious users as well; but those who are more serious will do better with the Pentax K-7 which records at 30 fps and has an external stereo microphone jack.

Flash

Pentax K-x Flash

The Pentax K-x features a built-in, pop-up flash, which operates in either Auto, Flash On (forced flash), Auto + Red-eye reduction, Flash On + Red-eye reduction, Slow-sync, Slow-sync + Red-eye reduction, Trailing Curtain Sync, or Wireless mode. The flash can automatically pop-up as needed in Auto Picture, Portrait, Macro, Night Portrait, or several of the Scene modes (Surf & Snow, Food, Kids, and Pet). In Night Scene, Sunset, Stage Lighting, Candlelight, and Museum modes, the flash is disabled altogether. In other modes, the flash is released from its compartment by pressing the Flash Up button to the left of the viewfinder. Close it again by pushing the flash head back down. The same button is used to disable the flash when it has popped up automatically, but you prefer not to use it.

The Pentax K-x's built-in flash has a guide number rating of 16 meters (52 feet) at ISO 200, or about 11.3 meters (37 feet) at ISO 100. That's a little weaker than most SLR built-in flashes (the average GN is about 12 meters), translating to a range of about 15 feet at ISO 200 with an f/3.5 lens. A Flash Exposure Compensation feature controls the flash exposure -2.0 to +1.0 stops in 1/2 or 1/3-stop increments. Maximum sync speed is 1/180 second, though if an external flash that supports high-speed sync is used, such as the Pentax AF540FGZ or AF360FGZ, maximum shutter speed with flash is 1/6,000 second.

In Wireless mode, the built-in flash can be used as a controller to multiple wireless slave flashes (including the Pentax AF540FGZ and/or AF360FGZ flash units). The built-in flash can be set to contribute to the exposure, or to act only as a controller. The Pentax wireless flash system offers four control channels, so up to four camera/flash setups can be used in the same area without interfering with each other. The K-x can connect on any of the four control channels: You program it by setting a flash unit to the desired channel, attaching that flash to the camera and then half-pressing the shutter button. This sets the camera to the channel the flash was set up for. After this, the flash may be removed and used as a remote unit, controlled by the camera.

Normally, all flashes used (whether on-camera or remote) contribute equally to the exposure, however each external flash can be set to one of the following ratios: 1/1, 2/3, 1/2 or 1/3. Additionally, each flash can be adjusted to under- or overexpose in 0.5 stop increments from -3.0 stops to +1.0 stop. All of this is relative to the overall flash exposure that can be adjusted on the camera by from -2.0 stops to +1.0 stop. Alternately, the Pentax flash units offer a Contrast-Control-Sync mode (CCS for short), which drops a flash's power. Units set to CCS mode can thus be used to provide "fill" illumination. When used with the K-x, and when the K-x's internal flash is also contributing to the exposure, the external flash in CCS mode will cut its output to two-thirds, while the K-x's built-in flash will cut its exposure contribution to one-third.

The Pentax K-x also has a top-mounted hot shoe for attaching an external flash unit. Like most consumer SLRs, a PC-sync terminal is not provided.

Flash Test Results

Coverage and Range
Good performance at close range, with uneven coverage at wide-angle. Lower than average exposure compensation required.

Coverage and Exposure. Flash coverage was uneven at wide-angle (18mm) with the 18-55mm kit lens. Coverage was much more uniform at telephoto (55mm). In the Indoor test, the Pentax K-x's flash required no exposure compensation adjustment to get good, albeit quite bright results. (Most cameras we've tested required about +0.7 EV for this scene.) The camera's Slow-Sync flash mode produced slightly bright but more even results with no exposure compensation, though with a stronger pinkish-orange cast from the room lighting.

Flash Range: Wide Angle
6 ft	7 ft	8 ft	9 ft	10 ft	11 ft
1/15 sec f3.5 ISO 100	1/15 sec f3.5 ISO 100	1/15 sec f3.5 ISO 100	1/15 sec f3.5 ISO 100	1/15 sec f3.5 ISO 100	1/15 sec f3.5 ISO 100
12 ft	13 ft	14 ft	15 ft	16 ft
1/15 sec f3.5 ISO 100	1/15 sec f3.5 ISO 100	1/15 sec f3.5 ISO 100	1/15 sec f3.5 ISO 100	1/15 sec f3.5 ISO 100

Flash Range: Telephoto
6 ft	7 ft	8 ft	9 ft	10 ft	11 ft
1/40 sec f5.6 ISO 100	1/40 sec f5.6 ISO 100	1/40 sec f5.6 ISO 100	1/40 sec f5.6 ISO 100	1/40 sec f5.6 ISO 100	1/40 sec f5.6 ISO 100
12 ft	13 ft	14 ft	15 ft	16 ft
1/40 sec f5.6 ISO 100	1/40 sec f5.6 ISO 100	1/40 sec f5.6 ISO 100	1/40 sec f5.6 ISO 100	1/40 sec f5.6 ISO 100

ISO 100 Range. At 18mm and ISO 100, flash shots started out bright at 6 feet, peaked in brightness at about 7 feet, and remained fairly bright out to about 11 feet. At 55mm, flash exposure was bright at 6 feet, but decreased in brightness from that point on.

Manufacturer-Specified Flash Range
Wide Angle	Telephoto
15.0 feet ISO 200	9.4 feet ISO 200

Manufacturer Specified Flash Test. The Pentax K-x's flash is rated with a GN of 16 meters at ISO 200. That translates to 4.6 meters or 15 feet at f/3.5, and 2.9 meters or 9.4 feet at f/5.6. In the shots above, the K-x performed about as Pentax says it will, producing good exposures at the rated distances. Our standard test method for flash range uses a fixed setting of ISO 100, to provide a fair basis of comparison between cameras. We've now also begun shooting two shots using the manufacturer-specified camera settings, at the range the company claims for the camera, to assess the validity of the specific claims.

High ISO Noise Reduction

Pentax K-x High ISO Image Quality

The Pentax K-x offers four high-ISO noise-reduction settings, allowing you quite a bit of flexibility in choosing how you want to make the trade-off between subject detail and noise levels. Settings available are "Off ", "Low", "Medium" (default), and "High". Like the Pentax K-7, the K-x has unusually flexible noise reduction options, letting you program at what ISO High ISO Noise Reduction starts, in addition to the levels. Options are ISO 400, 800, 1600 and 3200. The default is ISO 800, which is what we used.

See for yourself how the noise reduction works under daylight lighting. Click on any of the crops below to see the corresponding full-sized image.

Pentax K-x High ISO Noise Reduction Comparison Simulated Daylight
	HINR=Off	HINR=Low	HINR=Medium	HINR=High
I S O 8 0 0
	HINR=Off	HINR=Low	HINR=Medium	HINR=High
I S O 1 6 0 0
	HINR=Off	HINR=Low	HINR=Medium	HINR=High
I S O 3 2 0 0
	HINR=Off	HINR=Low	HINR=Medium	HINR=High
I S O 6 4 0 0
	HINR=Off	HINR=Low	HINR=Medium	HINR=High
I S O 1 2 8 0 0

The above crops show the effects of the four levels of High ISO Noise Reduction available on the Pentax K-x. The default setting is "Medium", but to our eyes it's a bit strong (except at ISO 800, where it seems to be weak - firmware bug?), so we're glad Pentax included "Low" and "Off" settings. Note that while our Pentax K-x Operating manual says that noise reduction is performed at ISOs above the start ISO, it is clear from the ISO 800 crops that noise reduction is applied at the start ISO. Also note that some noise reduction is always performed at ISO 6,400 and above, even with the Off setting.

Imatest Results

Pentax K-x Imatest Results

We routinely use Norman Koren's excellent "Imatest" analysis program for quantitative, thoroughly objective analysis of digicam test images. I highly recommend it to our technically-oriented readers, as it's far and away the best, most comprehensive analysis program I've found to date.

My comments below are just brief observations of what we see in the Imatest results. A full discussion of all the data Imatest produces is really beyond the scope of this review: Visit the Imatest web site for a full discussion of what the program measures, how it performs its computations, and how to interpret its output.

Here's some of the results produced by Imatest for the Pentax K-x:

sRGB Accuracy Comparison
Pentax K-x	Canon XSi	Nikon D5000	Olympus E-620	Sony A330

The Pentax K-x showed slightly lower than average color accuracy, and its default saturation is quite a bit higher than that of the competition. Average saturation was 121.4% (21.4% oversaturated), much higher than average for an SLR (the rest in this group are in the 4-5% oversaturation range). This is quite typical for a Pentax SLR, as the camera defaults to "Bright" Image Tone mode. Hue accuracy was good, but not great, with an average "delta-C" color error of 7.14 after correction for saturation, one of the lower SLR scores in recent memory. (Delta-C is the same as the more commonly referred to delta-E, but delta-C takes into account only color differences, ignoring luminance variation.) Overall, a good (albeit very vibrant) default color response for a digital SLR. Mouse over the links below the illustration above to compare results with other consumer models.

Adobe RGB Accuracy Comparison
Pentax K-x	Canon XSi	Nikon D5000	Olympus E-620	Sony A330

As is true of most SLRs, when using the Adobe RGB color space (which provides a much wider gamut, or range of colors that can be expressed), the Pentax K-x delivers even more highly saturated color than sRGB, with an average saturation of 129.2%. Average saturation-corrected hue error was 7.11 "delta-C" units, only slightly better than its sRGB results. Again, mouse over the links below the illustration above to compare results with other consumer SLRs.

This image shows how the Pentax K-x actually rendered the colors of the MacBeth chart, compared to a numerically ideal treatment. In each color swatch, the outer perimeter shows the color as actually captured by the camera, the inner square shows the numerically correct color after correcting for the luminance of the photographed chart (as determined by a second-order curve fit to the values of the gray swatches), and the small rectangle inside the inner square shows the numerically correct color, without the luminance correction. This image shows the slightly below-average hue accuracy and high saturation of most colors. It also shows the tendency towards a greenish tinge in the range of yellow through orange, as well as the significant saturation boost in greens and blues.

The bottom row of the chart shows exaggerated white balance errors, revealing that the camera produced a slightly cool color balance when using Custom white balance, with a WhiBal card as the reference. White balance is actually pretty close for midtone through highlight values (note that the examples above deliberately exaggerate the white balance error). It's somewhat worse in the shadows, but is also less visually apparent there.

There's a lot in this particular graph, a lot more than we have room to go into here. (This set of plots has also changed a few revisions back in Imatest. Some of the plots that were once shown here are now shown in other Imatest output. Since we largely focus on the Noise Spectrum plot, we only show the graphic above, which includes that plot.)

In comparing these graphs with those from competing cameras, we've found that the Noise Spectrum graph at lower right is the most important. Cameras that manage to shift their noise spectrum to higher frequencies have much finer-grained noise structures, making their noise less visually objectionable. In the graph above, this would show up as a noise spectrum curve that remained higher on the right side, representing higher noise frequencies.

Except for the red channel, the Pentax K-x does a pretty good job of keeping plenty of the noise energy at high frequencies. What little low-ISO image noise that's there is more fine-grained as a result. The red channel has a lot more low-frequency energy, but that seems to be fairly common these days, and chrominance noise is only slightly visible when inspecting dark midtones and shadow areas of low ISO shots very closely.

Looking at the lower-left and upper-right plots in the illustration above, the Pentax K-x's overall noise levels are lower than those of the K-7 at ISO 100. That's not surprising, since the Pentax K-7 has smaller photosites.

Above is the same plot for ISO 200, the Pentax K-x's default base ISO. Noise levels are a little higher than ISO 100, as you'd expect, but the noise spectrum plot is very similar. This translates to slightly higher noise, mainly in the shadows, but noise levels are still quite low.

Here's the same set of noise data at ISO 3,200. Here, the Noise Spectrum graph is shifted towards the left-hand, lower-frequency side than it was at ISO 200, though it's hard to tell because of the change in scale. This indicates a coarsening of the "grain" of the image noise patterns by quite a bit, and indeed that's what we see when inspecting the K-x's ISO 3,200 images, though there still a lot of fine detail left intact. The red, green, blue and luminance channels are almost perfectly in-line each other, indicating the Pentax K-x's default high ISO noise reduction is doing a very good job at keeping chrominance noise in check. Also note the channels in the noise level plots in the lower left and upper right track very closely as well.

Here's the same set of noise data at ISO 6,400. The Noise Spectrum graph is again quite similar, but notice the noise levels are much higher.

Here's the same set of noise data at ISO 12,800. Here you can see a dramatic shift to the left in the Noise Spectrum graph.

This chart compares the Pentax K-x's noise performance over a range of ISOs against that of other current consumer models. While we continue to show noise plots of this sort because readers ask for them, we each time point out that the noise magnitude is only a small part of the story, the grain pattern being much more important. Here, we can see that the Pentax K-x's luminance noise magnitude starts out about average relative to its APS-C sensor "competition," and stays about average or slightly below average up to ISO 800. At ISO 1,600, the K-x's noise magnitude is about the same as the Nikon D5000, lower than the Canon XSi and Olympus E-620, but higher than the Sony A330. At ISO 3,200, it's a bit higher the the D5000 and A330, but still much lower than the Olympus E-620. The K-x remains a littler higher than the D5000 at ISO 6,400, and is the only camera in the group to offer ISO 12,800. Overall, the K-x's graph is fairly linear, indicating a nice, progressive approach to noise reduction levels versus ISO sensitivity. Do keep in mind these measurements are at default settings, so the shape or position of the curve is influenced by the settings you choose to use. (The Pentax K-x offers Off, Low, Medium and High noise reduction options, plus a programmable start ISO ranging from ISO 400 to 3,200 in 1 EV steps. The default settings are Medium NR starting at ISO 800.)

Pentax K-x Dynamic Range Analysis

A key parameter in a digital camera is its Dynamic Range, the range of brightness that can be faithfully recorded. At the upper end of the tonal scale, dynamic range is dictated by the point at which the RGB data "saturates" at values of 255, 255, 255. At the lower end of the tonal scale, dynamic range is determined by the point at which there ceases to be any useful difference between adjacent tonal steps. Note the use of the qualifier "useful" in there: While it's tempting to evaluate dynamic range as the maximum number of tonal steps that can be discerned at all, that measure of dynamic range has very little relevance to real-world photography. What we care about as photographers is how much detail we can pull out of the shadows before image noise becomes too objectionable. This, of course, is a very subjective matter, and will vary with the application and even the subject matter in question. (Noise will be much more visible in subjects with large areas of flat tints and subtle shading than it would in subjects with strong, highly contrasting surface texture.)

What makes most sense then, is to specify useful dynamic range in terms of the point at which image noise reaches some agreed-upon threshold. To this end, Imatest computes a number of different dynamic range measurements, based on a variety of image noise thresholds. The noise thresholds are specified in terms of f-stops of equivalent luminance variation in the final image file, and dynamic range is computed for noise thresholds of 1.0 (low image quality), 0.5 (medium image quality), 0.25 (medium-high image quality) and 0.1 (high image quality). For most photographers and most applications, the noise thresholds of 0.5 and 0.25 f-stops are probably the most relevant to the production of acceptable-quality finished images, but many noise-sensitive shooters will insist on the 0.1 f-stop limit for their most critical work.

The image below shows the test results from Imatest for an in-camera JPEG file from the Pentax K-x with a nominally-exposed density step target (Stouffer 4110), and the K-x's settings such as Contrast and D-Range settings at their default positions. We used ISO 100 for the K-x, as Imatest dynamic range results were slightly better than ISO 200.

Here, we can see that the tone curve shows pretty good gradation in the highlights and the shadows trail off nicely too. Total dynamic range is good (at 10.6 f-stops), however the score at the highest level (7.18) is a little on the low side for a modern APS-C sensor SLR, likely in-part due to the K-x's slightly high default contrast and sharpening, which tends to amplify noise.

Processing the Pentax K-x's RAW (.DNG) files through Adobe Camera Raw (ACR) version 5.6 beta increased dynamic range by more than two full f-stops at the highest quality level (9.33) compared to the in-camera JPEG (7.18), while increasing total dynamic range from 10.6 to 11.4 f-stops. These results were obtained by using ACR's automatic settings, and we weren't able to do any better with manual adjustment. It's worth noting here is that ACR's default noise reduction settings reduced overall noise somewhat (see the plot in the lower left-hand corner) relative to the levels in the in-camera JPEG, which would tend to boost the dynamic range numbers for the High Quality threshold. Also, the extreme highlight recovery being performed by ACR here would likely produce color errors in strong highlights of natural subjects.

Dynamic Range, the bottom line:

The net result was that the Pentax K-x's JPEGs scored a bit below average in Imatest's dynamic range analysis when compared against other current APS-C sensor models. Pentax K-x RAW files converted with ACR did much better, placing the K-x in the top five cameras tested to date. When it comes to dynamic range (and high ISO noise), the K-x did much better than its more expensive sibling, the Pentax K-7.

To get some perspective, here's a summary of the Pentax K-x's dynamic range performance, and how it compares to other digital SLRs that we also have Imatest dynamic range data for. (Results are arranged in order of decreasing dynamic range at the "High" quality level.):

The results shown in the table are interesting. One of the first things that struck me when I (Dave) initially looked at test data for a wide range of DSLRs, was that here again, purely analytical measurements don't necessarily correlate all that well with actual photographic experience. There's no question that the Fuji S3 Pro once deserved its place atop the list, as its unique "SR" technology did indeed deliver a very obvious improvement in tonal range in the highlight portion of the tonal scale relative to competing models of its day. (Amazing that it's now surpassed by even consumer-level models using today's technology.) I was also surprised to see the analytical results place the original Olympus E-300 as highly as they did, given that our sense of that camera's images was that they were in fact noisier than those of many other DSLRs that we looked at. In the other direction, I was quite surprised to see the Nikon D2x place as low on the listings as it did, given that we found that camera's shadow detail to be little short of amazing.

One thing that's going on here though, is that we test each camera at its base ISO setting, which should produce best-case noise levels. This is in fact what many photographers will be most interested in, but it does perhaps place some of the Nikons (like the D40) at a disadvantage, as their lowest ISO setting is 200, as compared to the ISO 100 settings available on most other models.

When it comes to the Pentax K-x, as noted above, its somewhat low scores for camera JPEGs reflect Pentax' decision use slightly high contrast and sharpening at its default settings. You can see noise is more visible in the K-x's JPEGs than in dcraw-converted RAW files (look for JPEG files with the suffix _DCR), so sensor noise levels are not the issue here.

Pentax K-x Resolution Chart Test Results

The chart above shows consolidated results from spatial frequency response measurements in both the horizontal and vertical axes. The "MTF 50" numbers tend to correlate best with visual perceptions of sharpness, so those are what we focus on here. The uncorrected resolution figures are 1,371 line widths per picture height in the horizontal direction (corresponding to the vertically-oriented edge), and 1,477 lines along the vertical axis (corresponding to the horizontally-oriented edge), for a combined average of only 1,424 LW/PH. Correcting to a "standardized" sharpening with a one-pixel radius increased the resolution score by quite a bit, resulting in a much higher average of 1,992 LW/PH. The corrected numbers are slightly below what we'd expect from a 12-megapixel DSLR, though not too far off the mark.

To see what's going on, refer to the plots below, which show the actual edge profiles for both horizontal and vertical edges, in both their original and corrected forms. Here, you can see that very little if any in-camera sharpening is applied in the horizontal direction (undersharpened by 20.4 %), as well as in the vertical direction (18% undersharpened), explaining why standardized sharpening increased the MTF 50 numbers by a fair amount.

As with the K-7, we found these results a little paradoxical, given that we definitely saw sharpening artifacts in most of our "real world" images. (The far-field shot and the Still Life, in particular.) In-camera sharpening appears to vary depending on the density level of structures in its images. At very high and low densities (the black and white areas on the resolution target), it applies almost no sharpening at all. For densities away from the extremes of the tonal scale (the branches against the sky in our far-field shot and some of the details on the bottle labels in the Still Life shot), more sharpening is applied, resulting in slight halos around contrasting objects.

Overall (as is almost always the case), you'll extract the most detail from the Pentax K-x's images by careful processing of its RAW files.

RAW Files

Pentax K-x High ISO RAW Image Quality

We've recently started looking at RAW files converted with dcraw, an excellent freeware raw converter. dcraw usually offers timely support for the latest cameras, but more importantly, it does not apply any noise-reduction, sharpening or other corrections such as geometric distortion correction to the output files. (We found that Adobe Camera Raw still applies some limited noise-reduction when its NR settings are set to zero, and it also applies other corrections depending on the make and model of the camera). There will always be differences between RAW converters, in terms of the sort of demosaicing algorithms they use (the processes by which they convert the separate Red, Green, and Blue data sets to an array of full-color RGB pixels), but dcraw seems to use a fairly generic algorithm that delivers good sharpness with relatively few artifacts, and can be counted on to not apply any noise reduction if you don't want it to.

Below are crops from Pentax K-x high ISO RAW files compared to RAW files from the Canon XSi, Nikon D5000 and Olympus E-620, converted with dcraw.

High ISO Image Quality Pentax K-x vs Canon XSi, Nikon D5000 and Olympus E-620 RAW Comparison RAW files converted with dcraw, no NR, no sharpening Simulated Daylight
	Pentax K-x	Canon XSi	Nikon D5000	Olympus E-620
I S O 8 0 0
	Pentax K-x	Canon XSi	Nikon D5000	Olympus E-620
I S 0 1 6 0 0
	Pentax K-x	Canon XSi	Nikon D5000	Olympus E-620
I S O 3 2 0 0		N/A ISO 3200 not supported
		N/A ISO 3200 not supported
		N/A ISO 3200 not supported
	Pentax K-x	Canon XSi	Nikon D5000	Olympus E-620
I S 0 6 4 0 0		N/A ISO 6400 not supported		N/A ISO 6400 not supported
		N/A ISO 6400 not supported		N/A ISO 6400 not supported
		N/A ISO 6400 not supported		N/A ISO 6400 not supported
	Pentax K-x	Canon XSi	Nikon D5000	Olympus E-620
I S 0 1 2 8 0 0		N/A ISO 12800 not supported	N/A ISO 12800 not supported	N/A ISO 12800 not supported
		N/A ISO 12800 not supported	N/A ISO 12800 not supported	N/A ISO 12800 not supported
		N/A ISO 12800 not supported	N/A ISO 12800 not supported	N/A ISO 12800 not supported

Of the four SLRs in this group, the Pentax K-x generates the cleanest RAW files (and probably the cleanest from any recent APS-C sensor model we've tested thus far), though it does look like the camera may be applying some noise reduction to its RAW files at higher ISOs even when NR is turned "Off". The Nikon D5000 comes in second, and the Canon XSi is a close third. Not surprisingly, the Olympus E-620 is the noisiest, as it also has the smallest sensor of the group. Excellent performance from the Pentax K-x here, though we wish it wasn't applying any NR to its RAW files.

Menus

Pentax K-x Modes and Menus

Capture Modes

 Program mode: The Pentax K-x's Program mode can operate in several ways, depending on the camera's setup. By default, the K-x operates in Program Shift mode (some manufacturers refer to this as Flexible Program), which controls shutter speed and aperture automatically, but allows you to use the e-dial to bias the camera towards a faster shutter speed / wider aperture, or a slower shutter speed / narrower aperture.

The "e-dial in Program" setting under the Green Button submenu -- selected from page four of the Record menu -- allows this behavior to be changed, with the e-dial behavior being linked to the function assigned to the Green button. The e-dial can be disabled altogether, or set to switch the camera to either Shutter- or Aperture-priority Automatic (aka Hyper Shutter or Hyper Aperture) exposure -- but only if the Green button is programmed to reset the exposure to that calculated as optimal by the metering system. If the Green button is set to any other function, the e-dial is simply disabled in Program mode, and the camera takes complete control of both the shutter speed and aperture, while you control all other exposure variables.

In the Hyper modes, the e-dial can be set to directly take control of either the aperture or the shutter speed if adjusted after the Program exposure has been determined, effectively switching the camera to Aperture-priority or Shutter-priority for the current exposure only. The difference between this and Program Shift mode is that the Aperture or Shutter speed are explicitly fixed to your set value, rather than simply biasing the metering system while the camera still selects the actual values of both variables.

 Sensitivity Priority mode: Marked with an "Sv" for Sensitivity value, in this unusual mode you manually set the ISO by pressing the shutter button halfway, then turning the e-dial. The camera picks the Aperture and Shutter value accordingly.

 Shutter Priority mode: Marked with a "Tv," for Time value, this mode allows the user to control the shutter speed, from 30 seconds to 1/6,000 second.

 Aperture Priority mode: Marked with an "Av" for Aperture value, this mode gives user control of aperture, while the camera selects the shutter speed. Available apertures depend on the lens in use.

 Manual mode: This setting provides complete control over the exposure, with independent settings for aperture and shutter speed. The e-dial ordinarily controls shutter speed, and switches to aperture control if the exposure compensation button is held in (or pressed once before adjustment, and then a second time to confirm the aperture value change). Shutter speeds range from 1/6,000 to 30 seconds. Auto ISO sensitivity isn't available - if the camera is left on ISO Auto in M mode, the last set ISO value is instead used. The Green button ordinarily prompts the camera to meter the scene, and set both the aperture and shutter speed to obtain the metered exposure, much as would happen in Program mode. This metered exposure is then fixed until either the Green button is pressed again, or the photographer manually adjusts the aperture or shutter speed. Alternatively, the Green button can be set to adjust either the aperture or shutter speed alone to obtain a metered exposure, while the other variable is left to the manually set value. Finally, the Green button can be disabled altogether, requiring the photographer to set both exposure variables manually.

 Flash Off mode: Disables the flash strobe, and otherwise is identical in function to the Standard Auto picture mode described below.

 Night Scene mode: The symbol of a person with a crescent moon marks this mode on the Mode dial. Here, the camera employs a slower shutter speed and a synchronized flash to capture bright portraits in dark settings.

 Moving Object mode: An icon of a person running marks this mode on the Mode dial. The camera uses faster shutter speeds to "freeze" action on fast-paced subjects, and the drive mode is fixed to High-speed Continuous shooting.

 Macro mode: The traditional flower macro symbol indicates this mode on the Mode dial. Though actual macro focusing distances will depend on the lens in use, this mode optimizes the camera for capturing bright color in small subjects at close range.

 Landscape mode: The familiar mountain icon marks Landscape mode, which increases the focus range for sharp pictures of sweeping vistas. Saturation is boosted for bright skies and foliage.

 Portrait mode: An icon of a person's head and shoulders symbolizes this mode, which uses a larger aperture to decrease the depth of field, thereby producing sharply focused portraits in front of slightly blurred backgrounds. This mode also optimizes the camera for attractive skin tones.

 Auto Picture mode: This mode puts the camera in full control over the exposure, automatically selecting between the five previous scene modes - Portrait, Landscape, Macro, Moving Object and Night Scene -- as well as a Standard scene mode which isn't directly accessible from the Mode dial. In addition, when shooting in Live View mode, the Auto Picture mode can also select two further Scene modes - Blue Sky, and Sunset. The selected Scene mode is shown in the viewfinder info display, or at the top left corner of the LCD when shooting in Live View mode.

 Scene mode: Allows direct selection of ten scene modes, of which two can be accessed through other positions on the Mode dial as previously described. The available scene modes are Night Scene, Surf & Snow, Food, Sunset, Stage Lighting, Kids, Pet, Candlelight, Museum, and Night Snap. Night Scene also has its own Mode dial position, while Sunset can be automatically selected by the camera when using Auto Picture mode with Live View active.

 Movie mode: This mode allows the user to record videos with sound. Resolution options consist of 1280x720 (16:9) or 640x416 (3:2) pixels, both at 24 frames-per-second with monaural sound. There are three quality (compression ratio) options available, and you can choose to have the aperture fixed, or under automatic control. Shake reduction can also be enabled or disabled as desired. See the Video tab for more details as well as sample videos (if available).

Playback Mode

Playback mode is entered by pressing the Playback button on the camera's rear panel. In this mode, you can scroll through captured images, delete them, write-protect them, and apply digital filters for creative effects. You can also set them up for printing on devices capable of recognizing DPOF print orders specified on the flash card. Like the K-7 before it, the Pentax K-x is not PictBridge compatible, so the printer and camera can't be directly attached, however.

Pentax K-x Menu Details

Below are Pentax K-x menu options and their descriptions. Pressing the Menu button provides access to the camera's full menu system.

Record Menu:

Playback Menu:

Setup Menu:

Custom Menu:

Comparison

Pentax K-x Feature Comparison

The chart below compares the K-x with its bigger brother, the K-7, as well as its predecessor, the K2000. What we've done below is presented something of a hybrid comparison between these three models. A red cell means that a given camera performs below the other two, a green cell means that it performs better than the other two, and a yellow cell means it falls between the other two. In cases where two cameras share a superior capability, both cells will be colored green.

Press Release

PENTAX ANNOUNCES AFFORDABLE, NEW PENTAX K-x WITH HIGH-END FEATURES
INCLUDING HD VIDEO AND LIVE VIEW

GOLDEN, CO (September 16, 2009)… PENTAX Imaging Company redefines the entry-level digital SLR category with the introduction of the K-x digital SLR. This latest PENTAX camera offers high-end features including Live View and HD video. And, since there’s no rule that SLR cameras must come in black only, the K-x will be available in a choice of white or black, as well as special, limited edition red and navy.

Priced at $649.95 USD (for body with DA L 18-55mm lens), the extremely compact and lightweight PENTAX K-x forges ahead on the trail initiated by the popular PENTAX K2000. With a one-handed shooting design and simple, easy-to-use operation, the K-x is perfect for users stepping up from a point and shoot digital camera to their first digital SLR.

The PENTAX K-x offers photographic performance that challenges higher class DSLR models and offers several features that set this camera apart in the entry-level category:

• High resolution 12.4 megapixel CMOS image sensor features sensor-shift Shake Reduction for stabilized image and video capture up to 4 stops max.
• Large 2.7 inch LCD features Live View with contrast, phase difference, and Face Detection autofocus (up to 16 faces).
• Widescreen HD video capture in full 720p resolution (1280x720) at 24 FPS cinematic framerate, using any PENTAX 35mm lens.
• Creative processing and filter modes produce high quality finished images, while offering the ability to explore artistic freedom through unique special effects.
• True High Dynamic Range (HDR) image capture blends 3 bracketed images into a single picture with outstanding shadow, highlight, and midrange detail.
• Fast 4.7 FPS capture speed and 1/6000 second maximum shutter speeds are possible with the PENTAX PRIME II image processing engine.
• Powerful automatic modes, including PENTAX Auto Picture and scene modes, ensure the perfect shot in any situation, while helping new photographers learn DSLR photography.
• Responsive 11 point wide angle SAFOX VIII autofocus system focuses quickly and accurately, and can easily track moving subjects.
• Captures up to 1900 shots with universally available, easy-to-find AA lithium batteries (also compatible with AA NiMH rechargeable and alkaline batteries).

All combined, the PENTAX K-x is the perfect camera for new digital SLR camera users as well as an ideal backup camera for more experienced photographers.

Along with the K-x, PENTAX announced the smc PENTAX DA L 55-300mm F4-5.8 ED super-telephoto zoom lens. This lens will be exclusive to a K-x Twin Lens Kit package consisting of a K-x body, this new lens and the smc PENTAX DA L 18-55mm F3.5-5.6 lens. The lightweight design of this zoom lens offers the exceptional optical performance found in all PENTAX lenses for super-telephoto photography with the K-x and other PENTAX digital SLR camera bodies.

The PENTAX K-x is now available for pre-order in black or white on www.pentaxwebstore.com. Limited edition colors of red and navy will become available at select locations to be announced.

The PENTAX K-x (in black and white) will ship in October 2009 in three configurations: options:

• K-x single lens kit with body and an smc PENTAX DA L 18-55mm lens for USD $649.95.
• K-x twin lens kit for $749.95 including a K-x body, the smc PENTAX DA L 18-55mm lens and the smc PENTAX DA L 50-200mm zoom lens.
• K-x twin lens kit for $849.95 including a K-x body, the smc PENTAX DA L 18-55mm lens and the smc PENTAX DA L 55-300mm zoom lens.

Complete information is available here: www.pentaximaging.com/about-us.aspx?p=press
Product images are available here: www.pentaximaging.com/press/pressfiles.html
An informational video is available here: www.youtube.com/Pentaxian1

PENTAX Imaging Company is an innovative leader in the production of a variety of digital cameras including weather resistant digital SLRs and compact, waterproof cameras, as well as lenses, flash units, binoculars, scopes, and eyepieces. For 90 years, PENTAX has developed durable, reliable products that meet the needs of consumers and businesses. With headquarters in Golden, Colorado, PENTAX Imaging Company is a division of PENTAX of America, Inc.

# # #