Pentax Optio 550

A table of all the full digital images taken with the cameras

The Optio 550 is the first Pentax camera we've reviewed in the Labs. It's the cheapest 5-megapixel device here and, despite the slim dimensions, crams in a 5x optical zoom.

The design means the 550 is comfortable to hold and the controls are intuitively accessed via the top-mounted control dial and eight buttons at the rear. However, the out-of-the-way menu button proved a frustration when other cameras sensibly use the centre of the D-pad.

At 1.4in, the LCD is the smallest on show, although it proved very sharp, responsive and performed noticeably better in bright light than some others on show. This was a particular boon considering the optical viewfinder has an annoyingly low coverage.

Another downside was the slow startup time of over six seconds, just like the Casio. The inclusion of a 16MB SD card might appear stingy, but the lithium ion battery and charger easily make up for it.

Image quality fell below our expectations, though. Our selection of real-world images revealed generally poor dynamic range - details were lost in shadows and highlights bleached out. Focusing also proved too much on occasion, with many shots either slightly blurred or completely out of focus.

Our still life indoor shot exhibited similar problems. Contrast was poor from the underexposure and colours were undersaturated. Auto white balance sometimes failed and noise was evident. However, we saw little evidence of chromatic aberrations and resolution was average for a 5-megapixel device.

Macro ability using the Super mode almost rivalled the Nikon. The 550 managed to capture 32 x 24mm of our bank note, but barrel distortion was evident. Like the Coolpix 5400, the Optio 550 failed to correctly expose the portrait shot, deciding to focus on the background more often than our model and underexposing the scene.

We were impressed with the fast-charging flash, though, and the ability to remember settings when flicking through the control dial. Other highlights were the live histogram and the ability to add voice tags to captured images.

The Optio also offers a couple of unique features - a stereoscopic 3D mode and soft focus. The first allows you to take two similar shots of the same scene, print the pictures side-by-side and use the bundled stereoscope for a mildly exciting 3D effect. If 1970s-style glamour photography is your thing, the soft focus will appeal. If we're honest, though, both functions are gimmicks.

Overall, the 5-megapixel CCD doesn't help the 550 to produce good photos. For a similar price, the Olympus is a much better choice if you don't mind the extra bulk.