Pentax K-x Overview

Hands-on Preview Posted: 09/17/09

Pentax announces their second digital SLR camera this year, 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 4.7 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.

Expected to be available in October 2009, the Pentax K-x will ship in three configurations:

• Pentax K-x with 18-55mm DA L lens for $649.95
• Pentax K-x with 18-55mm DA L and 50-200mm DA L lenses for $749.95
• Pentax K-x with 18-55mm DA L and 55-300mm DA L lenses for $849.95

 

Pentax K-x Hands-on Preview

by Shawn Barnett and Mike Tomkins

After wowing us earlier this 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. Though we can't report on image quality, 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 my preview. 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 grip is good, with a good 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 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.

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 4.7 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.

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).

Three additional colors are available, with the Navy option looking less outrageous than the red or white.

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 is rated as 1,100 shots using lithium disposable batteries, to CIPA testing standards which include 50% flash usage. Both NTSC / PAL standard-definition video output and USB 2.0 High Speed computer connectivity are included.

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.