Canon PowerShot Pro90 IS

Professional digital cameras are mainly SLR (Single Lens Reflex) types and pricey, whereas amateur cameras (or prosumer as they're also known) are more compact and slightly less costly. The Canon PowerShot Pro90 IS, which resembles the ageing, yet respected PowerShot Pro70 (see Labs, issue 75, p92), is a hybrid digital SLR, that aims to bridge the gap in terms of both price and functionality.

The lens specifications of the Pro90 IS are impressive by any standards, featuring a fixed 13-element, 7-70mm 10x optical zoom lens (equivalent to 37-370mm), increasing by two or four times using the digital converter. Performance of the lens is equally admirable, with excellent sharpness at wide- to mid-range focal lengths, although it falls slightly at the telephoto setting. Distortions are kept well under control too, with an acceptable amount of barrel distortion on wide settings and pincushion on telephoto settings. However, at the long end of the zoom, chromatic aberrations were present at the edges of images.

The Pro90 IS is fitted with a 3.34 megapixel CCD. As the lens doesn't project a large enough image to cover the entire CCD, Canon has masked down the CCD capture area to give a 2.6 megapixel image. That said, for most practical uses you wouldn't see the difference between a 3.34 and 2.6 megapixel image.

Pictures can be shot in three resolutions: 1,856 x 1,392; 1,024 x 768; or 640 x 480. Each resolution has three levels of JPEG compression - Super Fine, Fine and Normal. Image quality at Super Fine is superb with virtually no JPEG compression artefacts, while shooting at Normal gives a greater number of images at the expense of image quality. For the purist, pictures can be captured in RAW format, giving an unprocessed image of RAW data as captured by the CCD, and there's also the option to shoot upto 30 seconds of AVI video at 320 x 240.

Although labelled an SLR, the Pro90 IS isn't a true SLR camera, as you view the image through a TTL (Through The Lens) electronic viewfinder, rather than an optical system. The Pro90 IS uses a miniature LCD display, which is a relay of the main LCD screen. Although the TTL viewfinder image is clear, it has a very fine screen pattern making it difficult to use the manual focus accurately. The viewfinder has a dioptre correction dial and the whole image is easily viewed whilst wearing spectacles. Like Canon's PowerShot G1 (reviewed issue 79, p189) the rear LCD screen can be swung out and rotated to almost any angle, giving tremendous scope to vary your shooting position. The screen can also be rotated 180 degrees and snapped back into the rear of the camera, like most typical LCD screens.

The camera has a variety of shooting modes - including Auto and Manual - plus a host of image control options, including Portrait and Mono modes. A complicated dial sets the various modes, but it can be mastered with practice. The manual settings give you the most control, allowing you to change shutter speeds and aperture settings. However, instead of an exposure indicator, the viewfinder image darkens or lightens as you alter the settings, which is logical and works well.

There's a choice of five ISO settings from 50 through to 400 and Auto. At 50, images are very smooth, but at 400 they tended to show more noise, similar to film grain. The exposure meter in the Pro90 IS is particularly good and delivered some of the most accurate exposures I've seen from any digital camera, with detail present in both highlight and shadow areas. The built-in pop-up flash also gave excellent exposures during our test period.