The Optio 550 is a great choice for anyone who wants a highly portable digital camera that doesn't sacrifice shooting flexibility or picture quality.We're still not sure how, but Pentax has managed to shoehorn a 5-megapixel CCD, a 5X zoom lens and loads of advanced features into the very compact dimensions of the Optio 550. And its images stand out from the crowd, too. If you are a serious photographer and want to cut some weight and bulk, take a close look at this Pentax.
With an aluminium-alloy body and a textured silver finish, the Optio 550 is good-looking but not especially striking. It feels quite solidly built, however, and its buttons and dials operate crisply. At 205g without the battery and the media installed (250g with battery and card), the 550 isn't exactly a featherweight, but it's no trouble to carry around. And its modest dimensions let it slip easily into any handy pocket.
Pentax has made an excellent job of placing the Optio 550's controls, although a handful of them are unlabelled, which confused us until we'd memorised their functions. You can access critical features rapidly via dedicated buttons or the four-way pad. When you must dive into the menu system, you'll find it nicely organised and labelled. You can easily view a dynamic histogram along with current setting information or activate a viewfinder grid with the Display button, and pressing Playback lets you quickly switch between shooting and image review without ever touching the mode dial.
The Optio 550 bristles with features, beginning with comprehensive exposure control: modes include programmed auto, aperture priority, shutter priority, and the highly functional manual. There are also nine scene modes, manual white balance plus seven presets, easily accessible exposure compensation and three light-metering systems: multi-segment, centre-weighted, and spot. The camera can also display a real-time histogram on its LCD, which is a great help in getting good exposures in any of the auto-exposure modes. Inexplicably--and inexcusably--the histogram does not reflect your exposure adjustments when you're in manual mode.
Exacting photographers will appreciate having the option to change image-processing parameters such as contrast, in-camera sharpening, and colour saturation. And the camera's multifaceted auto-bracketing function can snap three-shot bracketed sequences that adjust any of these parameters, as well as white balance and exposure. Additional items include a panorama-stitching assist mode, an interval-timer mode and a multiple-exposure feature for superimposing one image on another. You can also mess around with the camera's 3D mode, which shoots pairs of pictures that you can print and view in 3D with the provided plastic glasses.
The 550's lens covers a zoom range equivalent to 37.5mm to 187.5mm in 35mm-film-camera terms. Its f2.8-to-f4.6 maximum aperture is a bit narrow compared with that of some 'prosumer' digital cameras, but that's part of the price you pay for the Optio 550's small size.
You can capture still pictures as uncompressed TIFFs or as JPEGs at any one of three compression levels. We wish Pentax offered a RAW mode--RAW would do a better job than TIFF of combining high image quality, creative flexibility and fast file saving. On the other hand, annotating photos with voice captions is easy on the Optio 550, and a dedicated audio mode enables you to use the camera as a voice recorder. The Optio 550's movie mode captures 320-by-240-pixel QuickTime video with sound in clips up to 10 minutes long. And if you notice yourself channelling Charlie Chaplin, you can use the special fast-forward mode to give video a silent film's fast-motion look. (Pentax does not provide a glue-on moustache though.)
The Optio 550's performance, although adequate, isn't as impressive as its feature list. Start-up time is a middling 5 seconds, and we found overall shutter lag a bit longer than we'd prefer. That's largely because the autofocus speed is average at best. Low-light AF sensitivity, on the other hand, is pretty good. Shot-to-shot time when you're capturing JPEG files is quick at roughly 2 seconds, but with TIFF files it balloons to a frustrating but not atypical 20 seconds or more. The camera's comparatively lacklustre continuous-drive mode shoots four photos at about 1 frame per second before it pauses for about 10 seconds to clear the buffer.
The Optio 550's lens zooms quietly and smoothly, but you can't control its exact zoom position with as much precision as you should. In contrast, manual focus is quite precise, and the LCD shows a magnified view of your scene's centre portion to help you determine the correct focus. The LCD itself is fairly sharp and usable in both outdoor and low light. We preferred it to the optical viewfinder, which is acceptably sharp but small and a bit dim. The LCD and the viewfinder show approximately 100 percent and 86 percent, respectively, of the actual image.
The built-in flash's 5.2m maximum range (at ISO 100) is a bit better than average, but there is no slow-sync flash setting. You can get around this limitation in manual or shutter-priority mode, but it's still a baffling omission.
Our test images came out very well overall. Exposures, both flash and ambient, were consistently accurate. Sharpness and detail are first-rate, and the camera's photos will support good-quality enlargement to 11 by 14 inches or bigger.
Colours are generally pleasing and natural-looking, although yellows and occasionally blues tend to be a little under-saturated. Under indoor tungsten lighting, the Indoor white-balance preset delivered slightly cool images with a faint cyan cast, while the automatic white balance gave shots a very mild magenta cast.
To our surprise, the lens shows almost no barrel distortion at its wide-angle end and only modest pincushion distortion at its telephoto position. Remarkably few artefacts appeared in our pictures--even purple fringing, the curse of digital photography, was rare.
We did see moderate vignetting in the corners of some wide-angle photos with blue skies. This could be a problem if you shoot a lot of landscapes or architecture, but it's inconsequential for nearly all other scene types. We also noticed a smidgen more noise in our ISO 100 test shots than we've come to expect from the best 'prosumer' models. If you can get away with a lower sensitivity, ISO 50 images are super-clean. But results at the ISO 400 setting, as with all of the Optio 550's competitors, are quite noisy.
Pentax Optio 550
Company: Pentax
Price: AU$1,599
Distributor: C.R. Kennedy & Company
Phone: (02) 9518 9500
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