The Imaging Resource

Quick Review

Pentax Optio 550 Digital Camera

	Camera QuickLook
	Review Date	7/17/2003
	User Level	Novice to experienced amateur
	Product Uses	Family / Travel / Special Events
	Digicam Design	Point and Shoot / Full Manual Control
	Picture Quality	Good, 5.0-megapixel CCD
	Print Sizes	Good prints to 8x10 or larger
	Availability	Now
	Suggested Retail Price (At introduction)	$599

Camera Overview
Compact though just slightly more bulky in appearance than the rest of the Optio line, the Pentax Optio 550 features a rugged, metal body that can withstand a lot of wear and tear. Boasting a 5.0-megapixel CCD and 5x SMC Pentax lens, the 550 is a capable digicam with a very nice selection of features. Control layout is similar to other Optio models, though the 550 model is slightly larger than the more portable 430 RS. At 3.9 x 2.3 x 1.6 inches (100 x 59 x 39.5 millimeters) and 8.8 ounces (250 grams) with the battery and memory card, the Optio 550 is a bit large and heavy for most shirt pockets. The camera will, however, find a home in larger coat pockets and purses, and comes with a wrist strap for a little extra security. As with the preceding Optio models, the 550's compact design includes a built-in, shutter-like lens cover which opens when the lens telescopes out. At 5.0 megapixels, the 550's CCD produces high resolution, print quality images, with options for lower resolution, more email-friendly images as well.

The Optio 550 sports a 5x, 7.8-39mm SMC Pentax lens, the equivalent of a 37.5-187.5mm lens on a 35mm camera. (The "SMC" in the lens name stands for Super Multi Coating, Pentax' name for their advanced lens coating process. From past experience in the film world, I've observed that Pentax' SMC lenses did indeed have very good flare and contrast characteristics.) Apertures range from f/2.8 to f/7.9, depending on the zoom setting, and can be automatically or manually controlled. Focus ranges from 1.97 feet (0.6 meters) to infinity in normal shooting mode, with a Macro option covering from 6.0 inches to 1.6 feet (15 to 65 cm). Super Macro mode lets you focus even closer, from 0.8 inches to 2.13 feet (2 to 65 cm). (Normal Macro mode is available throughout the zoom range, while Super Macro is only available with the lens set to its full wide angle position.) The Optio 550 offers both manual and automatic focus (AF) control, with Spot and Wide AF modes. Spot AF mode bases focus on the very center of the frame or on one of five AF points around the center of the frame (selected via the Four Way Arrow pad). Wide AF mode judges focus from a larger area in the center of the frame. There's also an Infinity / Landscape fixed focus setting, particularly handy when shooting distant subjects at night, when there's not enough light for the camera to focus normally. In addition to the optical zoom, the Optio 550 offers up to 4x digital zoom, for an overall zoom capability of 20x. However, I always remind readers that using digital zoom decreases image quality, since it simply enlarges the center pixels of the CCD image.

You can choose between the real-image optical viewfinder or the 1.5-inch, color TFT LCD monitor to compose images. The LCD monitor offers an informative display in Record mode, reporting not only shutter speed and aperture settings, but also a wide range of basic exposure options. Additionally, the 550's LCD monitor features a grid display for aligning shots, and a histogram display for checking exposure. In my tests, the 550's optical viewfinder was a bit less accurate than average, showing between 77 and 81 percent of the final frame area, depending on the zoom position. By contrast, the LCD viewfinder is very close to 100% accurate. Kudos to Pentax for managing to provide an optical viewfinder at all on a 5x-zoom camera (many manufactures give up on optical viewfinders at this zoom level, resorting to electronic viewfinders (EVFs) instead. I personally greatly prefer optical viewfinders, as they tend to give a much clearer view of the subject, and are usable at light levels far lower than those typical EVFs work at. I'd still really like to see better optical viewfinder coverage than that offered by the 550's. (Most digicams have 85% viewfinders, which I still consider quite a bit too low - 90% should really be considered a minimum.) On a positive note, the 550's viewfinder has both a high eyepoint and a diopter adjustment control, making it particularly suited to use by eyeglass wearers.

Exposure can be manually or automatically controlled on the Optio 550, a nice feature for novices wanting to learn more about photography. The 550 gives you the convenience of automatic exposure when you want it, or full manual control when you'd like to experiment. An On/Off button on top of the camera controls the power, and a Mode dial lets you select between Manual, Shutter Priority, Aperture Priority, Program, Picture, Movie, Panorama Assist, 3D, Digital Filter, User, and Audio modes. Most exposure options are controlled through the LCD's on-screen menu system, which offers very straightforward navigation. That said, you can control focus mode (auto, macro, landscape, or manual), the self-timer, drive mode, exposure compensation, and the flash mode externally, reducing the number of times you'll have to enter the menu system in the first place. In Manual exposure mode, the user controls aperture and shutter speed (from 1/4,000 to eight seconds), in addition to all other exposure variables. Aperture and Shutter Priority modes give the user control over one variable, while the camera controls the other. Program mode keeps the camera in charge of the basic exposure, though the user maintains control over the rest of the available settings.

By default, the 550 uses a Multi-Segment metering system to determine exposure, which reads multiple points throughout the entire frame and considers both brightness and contrast in order to arrive at the correct exposure. However, Spot and Center-Weighted options are also available, handy for subjects either much brighter or much darker than their surroundings. Exposure Compensation is adjustable from -2 to +2 exposure equivalents (EV) in one-third-step increments. You can also adjust the camera's sensitivity setting, which offers ISO equivalents of 64, 100, 200, and 400, as well as an Auto setting. For times when not sure of the best overall exposure, the camera's Auto Bracketing mode can bracket either exposure, white balance, saturation, sharpness, or contrast. (An impressive range of bracketing options.) Auto Bracketing mode captures three images at different exposure settings (or any of the other values), and you can adjust the step size. The camera's White Balance setting features an Auto mode for average lighting conditions, but also offers Daylight, Shade, Tungsten, Warm Fluorescent, Neutral Fluorescent, Daylight Fluorescent, and Manual options. The Optio 550's built-in flash is rated as effective from 1.31 to 17.1 feet (0.4 to 5.2 meters) with the lens at full wide angle, or from 0.5 to 10.5 feet (0.15 to 3.2 meters) at the telephoto setting. Available flash modes are Auto, Off, On, Auto with Red-Eye Reduction, and On with Red-Eye Reduction. In my own tests, I found the 550's flash tended to underexpose the images slightly at all distances, but held roughly the same level of brightness out to about 12 feet.

In addition to the standard exposure modes, the Optio 550's Picture mode setting offers nine preset "scene" modes for shooting under unusual circumstances. Once in Picture mode, you can choose from Landscape, Night-Scene, Flower, Portrait, Surf & Snow, Autumn Colors, Sunset, Fireworks, and Text settings. Each mode addresses a specific shooting situation, and optimizes the camera for the best overall results. Panorama Assist mode lets you capture panoramic images, in either horizontal or vertical directions. Guide arrows appear on the LCD display to help you line up shots, and the accompanying software "stitches" images together into one panoramic frame on a computer. The 550 also offers a 3D recording mode, which debuted on the Optio 230 model and has since appeared on several models in the Optio line. In 3D mode, the camera produces three-dimensional "stereo pairs" of images similar to old-fashioned stereographs. The camera guides you to capture two images of the same subject (one just slightly off-center from the other) and then combines them as a "stereo pair" in a single frame of image memory. A transparent display of the first image captured remains on the LCD monitor, so that you can keep everything aligned as you move the camera over slightly and capture the second image. (Very slick, this eliminates one of the biggest problems with handheld 3D stereo photography.) A pair of 3D viewing glasses comes with the 550, and works whether viewing 3D images in the Parallel or Cross formats. (Parallel means you view the stereo photo with your eyes looking straight on, while Cross means that you cross your eyes to see the stereo effect. Most people seem to have an easier time with the Cross format, but the 550 supports either method.)

The 550 also has a nice range of creative tools, including a Digital Filter mode, which offers nine filters for special effects. Color filters include Black and White, Sepia, Red, Pink, Violet, Blue, Green, and Yellow, while a Soft filter softens the overall image. Image contrast, saturation, and sharpness settings provide further creative options, with minus/normal/plus settings available for each parameter. The User setting on the Mode dial lets you save a complete set of exposure adjustments so that they can be quickly recalled at a moment's notice. For example, if you frequently shoot in the same environment with the same lighting, saving a set of user options lets you quickly set up the camera without having to fish through LCD screens to make the adjustments individually.

In Movie exposure mode, the camera captures moving images with sound for a maximum of 10 minutes per movie (depending of course on the amount of available memory card space). Movies are recorded at a resolution of 320 x 240 pixels. Taking advantage of the disparity between the 320 x 240 movie resolution and the 2592 x 1944 resolution of the CCD, the Optio 550 provides a generous range of digital zoom in movie mode. (This is one case where there really isn't a downside to using digital zoom, since the final image represents a significant cropping of the CCD's pixel array anyway.) Because the digital zoom doesn't use the lens motor, it's possible to zoom during movie recording without worrying about zoom motor noise intruding on the soundtrack. (Most digicams with audio capability in their movie modes disable zooming during movie recording, for this very reason.)

The Optio 550 also features an Audio recording mode, which records audio-only for as long as the SD memory card has available space. (A 16-megabyte card can hold approximately 30 minutes of audio.) The 550 also lets you record short audio clips to accompany captured images, like a voice caption. Fast Forward Movie mode records movies using a slower frame rate to capture lengthy periods of motion (such as clouds moving across the sky), with capture ratios (the amount the camera will appear to speed up the action) ranging from x2 to x100. Interval mode snaps from two to 99 successive photos at programmable intervals ranging from 10 seconds to 99 minutes. A Self-Timer mode provides a 10-second delay between pressing the Shutter button and the camera actually taking the picture, allowing you to get into your own shots. A remote control is available as an accessory, meaning you can take your time arranging the shot before tripping the shutter with the remote. For shooting fast-action subjects, the Optio 550's Continuous Shooting mode captures a rapid series of images for as long as you hold down the Shutter button, much like a motor drive on a traditional 35mm camera. The space available on the memory card determines the maximum number of images the camera will capture in the series, and details like resolution, shutter speed, and the state of the camera's "buffer" memory determine the shooting interval. Finally, a Multiple Exposure mode lets you capture two images on top of each other, much like a double-exposure.

The Optio 550 stores images on SD/MMC memory cards, and comes with a 16-megabyte SD starter card. I strongly recommend buying at least a 32- or 64-megabyte card at the same time as the camera, so you don't compromise any shots for lack of memory space. The camera uses a D-LI7 rechargeable lithium-ion battery pack for power, and both a battery and external charger are included with the camera. Since the Optio 550 does not accommodate AA batteries (or any other form of commonly available battery), I also recommend buying an extra battery pack and keeping it freshly charged. The optional AC adapter might also be useful for preserving battery power when reviewing and downloading images, but I generally find that simply having a spare battery provides ample power capacity.

Basic Features

• 5.0-megapixel CCD, for images up to 2592 x 1944 pixels.
• Real-image optical viewfinder.
• 1.5-inch color TFT LCD monitor.
• Glass, 5x, 7.8-39mm lens, equivalent to a 37.5-187.5mm lens on a 35mm camera.
• 4x digital zoom.
• Program, Aperture Priority, Shutter Priority, and Manual exposure modes.
• Shutter speeds from 1/4,000 to eight seconds.
• Aperture range from f/2.8 to f/7.9, depending on lens zoom position.
• Built-in flash with five modes.
• SD/MMC card storage (16-megabyte card included).
• Power supplied by one D-LI7 rechargeable lithium-ion battery pack or optional AC adapter.
• ACDSee software and USB drivers included for both Windows and Mac platforms.

Special Features

• Movie and Fast Forward Movie (time-lapse) modes with sound.
• Audio recording mode.
• Continuous Shooting mode.
• Interval Shooting, Multiple Exposure, Auto Bracketing, Panorama Assist, and 3D modes.
• Nine preset "scene" photography modes.
• User mode for saving frequently-used exposure settings.
• 10-second Self-Timer for delayed shutter release.
• Remote-Control mode for use with optional remote control unit.
• Digital Filter mode with eight color filters for special effects and one Soft filter.
• Macro (close-up) and Super Macro lens settings.
• White balance (color) adjustment with eight modes, including a manual adjustment.
• Image Contrast, Sharpness, and Saturation adjustments.
• Multi-Segment, Center-Weighted, and Spot metering modes.
• Sensitivity setting with four ISO equivalents and an Auto setting.
• Wide and Spot AF area modes.
• DPOF (Digital Print Order Format) compatibility.
• USB cable for connection to a computer (driver software included).

Recommendation
The Optio 550 is the next generation in the Optio line of digicams, offering a larger 5.0-megapixel CCD and an impressive 5x zoom lens. Packed with features, the 550 offers automatic, manual, or partial manual exposure control, with a host of bells and whistles to excite any level user. A range of preset shooting modes tackle difficult shooting situations, and a host of creative effects and capture modes are fun to play with. Compact and sturdy with it's metal body, the Optio 550 is a great option for just about any experience level, from novice to enthusiast.

Design
With a fairly compact size and familiar Optio styling, the Optio 550 bears a strong resemblance to its predecessors in control layout and overall design. A few small protrusions interrupt the otherwise smooth case design, but don't protrude far enough to interfere when sliding the camera in or out of a pocket. With the lens stowed, the Optio 550 measures 3.9 x 2.3 x 1.6 inches (100 x 59 x 39.5 millimeters), which is just a bit too large for most average shirt pockets. Still, the 550 should fit easily into larger coat pockets and purses, and comes with a wrist strap. The camera's metal body may add a little heft, as the camera weighs 8.8 ounces (250 grams) with the battery and memory card in place.

The front of the camera holds the lens, flash, optical viewfinder window, flash sensor, self-timer lamp, tiny microphone port, and the sensor window for the optional remote control. A shutter-like, retractable lens cover protects the lens whenever the camera is powered off, sliding quickly out of the way when the camera is turned on. The lens then telescopes out from the camera body about an inch. The front of the camera is flat without any ridges to provide purchase for your fingers, making the grip a little more tenuous than I'd like. As a result, I'd recommend keeping the wrist strap securely around your wrist when holding the camera.

The opposite side of the camera is featureless and smooth.

The Optio 550's top panel features the speaker, Mode dial, Shutter button, and Power button.

A handful of external controls dot the camera's back panel, along with the optical viewfinder eyepiece and 1.5-inch color LCD monitor. Two LEDs next to the optical viewfinder report camera status, such as when focus is set, when the flash is charged, etc. At the top of the optical viewfinder eyepiece is a diopter adjustment control, which adjusts to accommodate eyeglass wearers. To the left of the viewfinder eyepiece are three multi-function buttons, which access different settings in Playback and Record modes. In the top right corner is the optical zoom control, which also controls playback zoom. A Four Way Arrow pad dominates the center of the back panel, with an "OK" button in the middle for confirming menu selections. The three remaining controls are the Menu, Display, and Playback buttons.

On the bottom panel of the Optio 550 are the tripod mount and battery / memory card compartment. The plastic, threaded tripod mount is just off-center from the lens because of the camera's small size, but provides a fairly stable mount. The battery compartment features a sliding, hinged door, too close to the tripod mount to allow quick battery changes while working with a tripod. (Not likely a concern for the typical user of this camera though, given its highly portable design.)

Camera Operation
The Optio 550's user interface is similar to previous Optio models, with only a few external controls and a fairly concise LCD menu system. For standard point-and-shoot operation, the most basic features such as flash, focus mode, and zoom are all adjusted via external controls. The Mode dial lets you quickly set the camera's main operating mode, with just a turn of the dial. When it is necessary to enter the LCD menu system, you'll find it simple to navigate. Three menus are available, delineated by subject tabs at the top of the screen. The arrow keys of the Four Way Arrow pad scroll through each selection, and the OK button in the center of the pad confirms any changes. You can also program the arrow keys of the Four-Way Arrow pad to control specific exposure functions, and the User mode setting makes it easy to recall complex combinations of frequently used settings. It shouldn't take much more then a half-hour or so to become familiar with the basic camera setup, as it's fairly intuitive, but learning the full range of functions will likely take most users an hour or more.

Record-Mode Display
In record mode, the LCD monitor displays the subject with a small amount of overlaid information, indicating flash, macro and continuous or self-timer modes, date and time, battery charge level, and the number of images that can be stored on the remaining memory card space at the current size/quality setting. Pressing the Display button beneath the LCD once brings up a real-time histogram display, as well as additional overlaid information including images size and quality settings, white balance and autoexposure modes, and ISO setting. Pressing the Display button a third time turns on a grid of horizontal and vertical lines to help align your subjects, pressing it once more turns the LCD off entirely, and pressing it again restores the default display. When you half-press the shutter button, the central brackets turn green to indicate that focus is locked, or disappear if the camera isn't able to focus, and the shutter speed and aperture the camera will use are displayed in the lower left-hand corner of the LCD screen. The screenshot above right shows all the available record-mode display screens, in sequence..

Playback-Mode Display
In playback mode, the default image display shows the most recently captured image, with date and time of capture and file number, along with an overlay on the right-hand side that includes a microphone icon, indicating that you can record an audio annotation for the current image. (When an image already has an audio clip associated with it, a green-arrow "playback" symbol appears above the microphone icon, and a small icon of a music note appears in the upper right-hand corner of the display.) Pressing the Display button once adds a histogram display and an overlay with exposure details (the same histogram, overlay and details as in record mode), while pressing it a second time clears the screen of all overlays, showing the image by itself. A third press restores the default display screen. Pressing the wide-angle side of the zoom lever in playback mode shows an index display of images in the camera's memory, nine thumbnails at a time. Pressing the telephoto side of the zoom lever zooms into the image in small increments, with a maximum magnification of 8x. The screenshot above right shows the playback-mode display screens.

External Controls

• Manual Record: Provides total exposure control to the user, including aperture and shutter speed settings.
• Shutter Priority (Tv): Allows the user to adjust the shutter speed, while the camera selects the best corresponding aperture.
• Aperture Priority (Av): Operates similarly to Shutter Priority mode, only the user now controls the aperture while the camera adjusts the shutter speed.
• Program: In this mode, the camera controls both aperture and shutter speed settings, while the user has access to all other exposure variables.
• Picture: Accesses nine preset shooting modes, including Landscape, Night-Scene, Flower, Portrait, Surf & Snow, Autumn Colors, Sunset, Fireworks, and Text scenes.
• Movie: Records moving images with sound, for a maximum of 10 minutes per movie. (Actual recording times will depend on the amount of available memory card space.)
• Panorama Assist: Assists the user in recording a series of images to be stitched together on a computer as a single panoramic image. (A "ghosted" portion of the edge of each previous picture is shown on the LCD screen as an aid to aligning the next photo in the series. Exposure and white balance are locked on the first shot.)
• 3D: Records a stereographic pair of images in a single frame, for viewing as 3D images using the viewing glasses included with the camera. (A fun feature, IMHO.)
• Digital Filter: Offers a selection of eight color filter modes, as well as a "Soft" filter for softening images.
• User: Lets the user save a set of exposure settings, for instant recall.
• Audio: Records only audio, with the amount of available recording time limited only by the memory card space.

In Manual exposure mode, the up and down keys adjust the aperture setting, while the left and right keys change the shutter speed. In Aperture and Shutter Priority modes, the up and down arrows adjust the available variable. In all Record modes except for Manual, the left and right keys adjust the exposure compensation, from -2 to + 2 exposure equivalents (EV) in one-third-step increments. In Digital Filter and Picture modes, the up and down arrows scroll through the available filters or presets. In Playback mode, the left and right keys scroll through captured images on the memory card.

Through the Setup menu, any of the four arrow keys can be assigned a specific function.

OK Button: Nestled in the center of the Four Way Arrow pad, this button confirms menu selections in any mode. In Playback mode, this button allows you to record a short sound clip to accompany the recorded image.

• Record Mode Settings
  • Resolution: Sets the image resolution to 2,592 x 1,944; 2,048 x 1,536; 1,600 x 1,200; 1,024 x 768; or 640 x 480 pixels.
  • Quality level: Sets the JPEG compression level to Good, Better, or Best (three stars being Best and one star being Good). A TIFF option is also available.
  • White Balance: Adjusts the overall color balance of the scene. Options include Auto, Daylight, Shade, Incandescent, Warm Fluorescent, Neutral Fluorescent, Daylight Fluorescent, and Manual. (Manual white balance lets you use a white object to set the camera's color balance. This is an unusual feature to find in a primarily "point-and-shoot" camera.)
  • Focusing Area: Designates the area of the frame that the camera determines focus from, either Spot or Wide. Spot AF lets you pick one of five AF areas, or use the default center area to determine focus. Wide mode bases focus on a large area in the center of the frame.
  • AE Metering: Chooses how the camera determines exposure, choices are Spot, Center-Weighted, and Multi-Segment.
  • Sensitivity: Adjusts the camera's light sensitivity, options are Auto, or 64, 100, 200, or 400 ISO equivalents.
    
    
    
  • Auto Bracket: Selects the type of auto bracketing sequence, and the step size between exposures. Options are Exposure, White Balance, Sharpness, Saturation, and Contrast.
  • Digital Zoom: Turns the 4x digital zoom on and off. When enabled, the digital zoom kicks in after you've zoomed the optical lens all the way to its telephoto position.
  • Instant Review: Turns the Instant Review function on or off. If on, sets the review time on the LCD screen to 0.5, 1, 2, 3, 4, or 5 seconds.
  • Interval Shooting: Activates the Interval Shooting mode, and lets you designate the time interval between shots, the number of shots to record in a series, and how long to wait before beginning shooting. Intervals can range from 30 seconds to 99 minutes, the number of shots captured can range from 2 to 99, and the delay before starting can run from 1 minute to 3 hours 59 minutes.
  • Fast Forward Movie: Turns on the Time Lapse Movie mode, which uses a slower frame rate to capture long periods of activity. Frame interval settings extend from x2 to x100 (referring to the rate of relative playback speed).
  • 3D Mode: Sets the 3D recording mode to Cross or Parallel. (Cross means you need to cross your eyes slightly to see the 3D effect. Parallel means you need to look straight ahead, actually slightly "wall-eyed."- Most people find the crossed-eye method easier.)
    
    
    
    
  • Memory: Lets you decide which settings will be remembered when the camera is shut off. Any setting not selected returns to the default setting whenever the camera is turned off and back on again. Features that can be remembered include Flash, White Balance, EV Compensation, Digital Zoom, AE Metering, ISO Speed, Focus Mode, Zoom Position, MF, Display, and File Numbering.
  • Sharpness: Adjusts the overall image sharpness to Normal, Hard, or Soft.
  • Saturation: Controls the level of color saturation. Options are Normal, High, or Low.
  • Contrast: Adjusts overall image contrast to Normal, High, or Low.
    

• Playback
  • Resize: Resizes the selected image to smaller pixel dimensions.
  • Trimming: Crops an image and saves it as a smaller file.
  • Alarm: Turns on the camera's alarm clock function, and lets you set as many as three alarm settings.
  • Slideshow: Specifies the display interval for images in a slideshow playback, from three to 30 seconds.
    
    
    
    
• Setup
  • Format: Formats the SD/MMC card, erasing all files (even protected ones).
  • Sound: Adjusts the volume of the camera's overall sound, and assigns specific sounds to startup, shutter, and operation functions.
  • Date Style: Cycles through available date formats.
  • Date Adjust: Sets the camera's internal date and time.
  • World Time: Allows you to set the time in another city, so that you can display the time in London, for example, on the LCD monitor. A full list of cities is in the manual.
    
    
    
  • Language: Changes the menu language to English, French, German, Spanish, Italian, or Japanese.
  • Start-up Screen: Determines what image is displayed when the camera is powered on. The "Optio" screen is the default, but you can select any image from the SD/MMC card.
  • Video Out: Sets the video format to NTSC or PAL.
  • Sleep Timeout: Disables the Sleep function, or sets the camera to go to sleep after 30 seconds, one, or two minutes of inactivity.
  • Auto Power Off: Turns this feature off, or sets the camera to shut off after three or five minutes of inactivity.
  • Quick Delete: When activated, this function displays the Delete screen (whenever the Flash / Erase button is pressed in review mode) with "All Images" automatically selected.
    
    
    
  • Quick Zoom: When turned on, this function enlarges images to the full resolution size with only one press of the zoom toggle button.
  • Function Setting: Assigns specific exposure functions to the arrow keys of the Four Way Arrow pad.
  • Focus Limiter: If turned on, this feature limits the movement of the lens when shooting.
  • Reset: Resets all camera settings to their defaults.

• D-Ll7 rechargeable lithium-ion battery pack.
• Battery charger with AC plug cord.
• USB cable.
• Neck strap.
• 3D image viewer.
• 16-megabyte SD memory card.
• Software CD.
• Operating manual and registration card.
  

Recommended Accessories

• Large capacity SD memory card. (I'd recommend 32MB as a bare minimum, 64MB would be preferable.)
• Additional D-LI7 lithium-ion battery pack.
• AC adapter.
• Small camera case.
• Remote control.

Recommended Software: Rescue your images!
Just as important as an extra memory card is a tool to rescue your images when one of your cards fails at some point in the future. I get a lot of email from readers who've lost photos due to a corrupted memory card. Memory card corruption can happen with any card type and any camera manufacturer, nobody's immune. A surprising number of "lost" images can be recovered with an inexpensive, easy to use piece of software though. Given the amount of email I've gotten on the topic, I now include this paragraph in all my digicam reviews. The program you need is called PhotoRescue, by DataRescue SA. Read our review of it if you'd like, but download the program now, so you'll have it. It doesn't cost a penny until you need it, and even then it's only $29, with a money back guarantee. So download PhotoRescue for Windows or PhotoRescue for Mac while you're thinking of it. (While you're at it, download the PDF manual and quickstart guide as well.) Stash the file in a safe place and it'll be there when you need it. Trust me, needing this is not a matter of if, but when... PhotoRescue is about the best and easiest tool for recovering digital photos I've seen. (Disclosure: IR gets a small commission from sales of the product, but I'd highly recommend the program even if we didn't.) OK, now back to our regularly scheduled review...

Specifications
See the specifications sheet here.

 

Picky Details
Information on shooting speed, battery life, etc. can be found here.

 

Test Images
See my test images and detailed analysis here. The thumbnails below show a subset of my test images. Click on a thumbnail to see the full-size photo.

Outdoor	Indoor Flash	Indoor
House	Musicians	Macro
Davebox	Resolution	Viewfinder Accuracy

"Gallery" Photos
For those readers interested in a set of less "standardized" photos from the 550, here are some thumbnails of more random shots snapped with it. Click on one any of the thumbnails below for a larger view. Click on the larger view again to see the original image from the camera. (Photos in this gallery were shot by Gibbs Frazeur or Stephanie Boozer. Thanks Gibbs and Stephanie!)

NOTE: that these are big files, so be aware that (a) they'll take a while to download, and (b) they'll chew up a pretty good chunk of bandwidth on us. (Read the "support this site" blurb at the top the carrier pages, and think about it while you're waiting for the images to download.

NOTE TOO: Some browsers have difficult with very wide images, and distort them a lot when they display them. (I don't know about others, but IE 5.0 on the Mac definitely does this. If the full-sized images appear to be stretched horizontally, you may need to just download them to your hard drive and view them in an imaging application, or possibly try another browser.)

YIMGP0156.JPG 3,033.1 KB Shutter: 1/ 501 Aperture: F4.5 Exposure EV: 13.3 ISO Speed: 100	YIMGP0159.JPG 2,543.4 KB Shutter: 1/ 347 Aperture: F5.6 Exposure EV: 13.4 ISO Speed: 100	YIMGP0164.JPG 2,699.4 KB Shutter: 1/ 511 Aperture: F5 Exposure EV: 13.6 ISO Speed: 100
YIMGP0166.JPG 2,639.5 KB Shutter: 1/ 185 Aperture: F6 Exposure EV: 12.7 ISO Speed: 100	YIMGP0169.JPG 2,733.4 KB Shutter: 1/ 368 Aperture: F4.3 Exposure EV: 12.7 ISO Speed: 100	YIMGP0172.JPG 3,233.5 KB Shutter: 1/ 559 Aperture: F7 Exposure EV: 14.7 ISO Speed: 100
YIMGP0174.JPG 2,379.6 KB Shutter: 1/ 401 Aperture: F5.6 Exposure EV: 13.6 ISO Speed: 100	YIMGP0178.JPG 2,793.6 KB Shutter: 1/ 467 Aperture: F5.6 Exposure EV: 13.8 ISO Speed: 100	YIMGP0180.JPG 2,898.3 KB Shutter: 1/ 627 Aperture: F6.5 Exposure EV: 14.6 ISO Speed: 100
YIMGP0184.JPG 2,178.3 KB Shutter: 1/ 542 Aperture: F5.6 Exposure EV: 14 ISO Speed: 100	YIMGP0188.JPG 2,778.9 KB Shutter: 1/ 343 Aperture: F4 Exposure EV: 12.4 ISO Speed: 100	YIMGP0191.JPG 2,846.6 KB Shutter: 1/ 467 Aperture: F5.6 Exposure EV: 13.8 ISO Speed: 100
YIMGP0194.JPG 1,809.8 KB Shutter: 1/ 399 Aperture: F5 Exposure EV: 13.2 ISO Speed: 100

 

Test Results

As with all Imaging Resource product tests, I encourage you to let your own eyes be the judge of how well the camera performed. Explore the images on the pictures page, to see how the Optio 550's images compare to other cameras you may be considering.

• Color: The Optio 550's color was generally very good, producing pleasing results most of the time. All of the white balance settings typically produced very good results, with only very slight color casts. Colors were hue-accurate and appropriately saturated, neither too bright nor too dull. Skin tones were also very good, and the camera's white balance system handled the very difficult household incandescent lighting of my Indoor Portrait test with aplomb. All in all, an excellent performance in the color department.
  
  
• Exposure: While it performed well in my outdoor shooting (requiring only as much exposure compensation as other cameras I've tested do), the Optio 550's exposure system tended to produce dim exposures indoors, especially in the studio shots. I typically boosted the exposure to either +0.3 or +0.7 to get a proper exposure in the studio, something that is quite unusual in my experience. Fortunately, the exposure compensation is very easy to set, and the optional histogram overlay really helps judge if the exposure is set correctly. Still, I'd have preferred better exposure accuracy in the first place, from the camera's automatic system.
  
  
• Resolution/Sharpness: The Optio 550 performed very well on the "laboratory" resolution test chart. It started showing artifacts in the test patterns at resolutions as low as 1,000 lines per picture height, in both horizontal and vertical directions. I found "strong detail" out to at least 1,200 lines. "Extinction" of the target patterns didn't occur until about 1,450 lines.
  
  
• Closeups: In its "Super Macro" mode, the 550 does indeed deliver "super" macro performance, with a tiny minimum area of only 1.04 x 1.38 inches (16 x 35 mm). In normal macro mode, the minimum area is a slightly large 4.61 x 3.46 inches (117 x 88 millimeters). Resolution was very high, with great detail in the dollar bill, coins, and brooch. Details were also quite sharp, though with slight softness in the corners. Exposure was pretty good, though the corners of the frame were slightly dark. The Optio 550's flash had trouble throttling down for the macro area, overexposing the shot, and is completely unusable in Super Macro mode. (Plan on using external illumination for close-in macro shots.)
  
  
• Night Shots: The Optio 550 has a maximum exposure time of eight seconds, and a variable ISO setting, which serve the camera well in low-light shooting conditions. In my testing, the 550 produced clear, bright, usable images down to the 1/8 foot-candle (1.3 lux) light level, with good color at the 400 ISO setting. (Though just slightly dim, you could arguably use the image taken at the 1/16 foot-candle, 0.67 lux, light level.) Minimum usable light level closely tracked ISO all the way back to ISO 64, with which images were bright only as low as one foot-candle (11 lux). The 550's low-light Achilles' heel was autofocus performance though. It could only focus reliably down to just under one foot-candle (11 lux), as it has no AF-assist illuminator. Since average city street lighting at night equates to about one foot-candle, the Optio 550 will work well for city night scenes. It can bring back good-looking pictures from darker environments, but you'll need to plan on focusing manually in those situations. The Optio 550 does a good job managing image noise too: There's no hot-pixel noise evident anyplace in these shots, and while the noise level is generally higher than average, the grain pattern is very tight and uniform, making the noise that is present less objectionable (IMHO, anyway) than that from cameras with more open, blotchy noise patterns.
  
  
• Viewfinder Accuracy: The Optio 550's optical viewfinder proved quite tight, showing about 77 percent of the final frame area at wide angle, and about 81 percent at telephoto. Also, my evaluation unit seemed to have had a slightly shifted CCD, as the images framed with the optical viewfinder were tilted toward the lower left corner. The LCD monitor was much more accurate, showing approximately 97 percent accuracy at wide angle, and about 99 percent at telephoto. Since I like LCD monitors to be as close to 100 percent accuracy as possible, the Optio 550's LCD monitor performed well here.
  
  
• Optical Distortion: Optical distortion on the Optio 550 is about average at the wide-angle end, where I measured an approximate 0.54 percent barrel distortion. The telephoto end fared about the same, as I measured a 0.62 percent pincushion distortion. The barrel distortion figure is a bit lower than the 0.8% average I've found among cameras I've tested (which is too high, IMHO), but the pincushion figure is a fair bit higher than average. On the other hand though, the 550 does have a 5x zoom lens, making for a tougher optical design than a typical 3x lens would. Chromatic aberration is very low, showing only relatively faint color on either side of the target lines. (This distortion is visible as a very slight colored fringe around the objects at the edges of the field of view on the resolution target.)
  
  
• Battery Life: The Optio 550's battery life is quite a bit better than average for a compact digicam, with a worst-case run time of a bit over two hours. I still highly recommend purchasing a second battery right along with the camera, but the 550 does indeed do better than most in this key category.

Conclusion

The Optio 550 well deserves its place at the top of Pentax' digicam lineup. With a 5 megapixel sensor and sharp 5x optical zoom lens (with an optical viewfinder as well), the 550 delivers sharp, high-resolution images with excellent color and tone. Battery life is also surprisingly good for a relatively compact digicam. My minor complaints include somewhat higher than average image noise, an optical viewfinder that's a bit too "tight" (although I'm overall happy to find an optical VF at all on a digicam with a 5x zoom lens), and an exposure system that slightly underexposed shots indoors and in the studio. The viewfinder and exposure quirks aren't hard to compensate for, and the image noise, while high, is much better-behaved than that on most digicams I test, with a uniform, tight "grain pattern." All in all, the 550 is a great little camera, with a surprising range of features and capabilities. If you're in the market for a compact 5-megapixel digicam, the Optio 550 deserves close attention. (Definitely a "Dave's Pick.")