This latest addition to Canon's ever-expanding range of digital cameras is the replacement for the well-received PowerShot S1 IS. A compact ultra-zoom model, the main differences between this and its predecessor are a much-needed boost from 3.2-megapixels to a more respectable 5-megapixels, and an upgraded lens that now allows 12x optical zoom, as opposed to 10x on the old model.

Those major changes aside, there's little on the cosmetic front that enables you to tell the cameras apart. The S2 IS has a slightly more rectangular look, with fewer curves, but it still boasts the same right-hand grip, chunky lens housing and silver colouring. It's relatively light considering the options on board, and the supplied strap and lens cover let you to walk around for long periods with it secured comfortably around your neck.

The obvious reason people would buy this camera over a standard compact is the lens, so we'll start off looking at that. This is the real highlight of the S2 IS, offering an impressive 12x zoom; the equivalent of 36-432mm on a film camera. Obviously with this kind of reach, image stabilisation is key, and Canon has come up trumps here with an excellent implementation of its Image Stabiliser (the IS suffix on the S2's model number) technology. It works really well, enabing you to shoot at relatively slow speeds even at maximum telephoto without too much blur or much in the way of unsightly edge effects.

Considering that it's set in such a small body, the lens' ultrasonic motor is respectably quiet, and reasonably fast at moving between its extremes. The lens' maximum aperture runs from an impressive f2.7 at wide-angle to reasonable f3.5 at maximum zoom, offering you the chance to shoot in low light with a satisfactory shutter speed. Still, if you're somewhere where you can happily use fl ash, then you'll be well served by the comprehensive range of options available, from basic red eye reduction and slow synch to a trio of power adjustment settings.

Quick off the blocks

The camera's got nippy shooting and processing times thanks to the inclusion of Canon's DIGIC II processor, usually found on the brand's high-end SLRs. This allows for impressive 2.4fps burst shooting, and the S2 IS's bracketing options are also helped by this rapid-fi re approach.

DIGIC II also speeds up the autofocus by around 45 per cent from the S1. However, if you're in the mind to go completely manual, then the Manual Focus option will also prove an attraction.

In fact, this camera's well loaded when it comes to manual control, with the comprehensive mode dial offering easy access to a number of options from fully automatic to completely manual via a number of scene modes and a custom setting that'll remember your preferences for a specific type of shot. Metering is also well served, with a range of spot, centre-weighted, and evaluative options, plus speed equivalents up to ISO 400.

There's a fair number of white balance options on offer, ranging from the standard automatic setting to the much more useful evaluative setting. Here you set the balance by filling the screen with a grey card or piece of white paper before taking your shot. It's easy to do (press the Set button that sits below your thumb when shooting) and it produces images with the most natural colours.

However, it's not all good news, and the S2 IS rather lags behind the pace of the competition when it comes to viewfinders and displays. While the flip-out LCD has grown from 1.5-inches to a more respectable 1.8-inch model, its 115,000 pixels still leave a little to be desired.

There's no live histogram on offer, but in the Playback menu you can choose to have one displayed over the resulting shots. You can also choose to have blown-out areas of the shot brought to your attention by flashing - which can come in handy at times. Still, the LCD's a better bet than the electronic viewfinder, which makes focusing and checking your shots tricky as there's not enough detail on display.

The camera's powered by four AA cells, and it's a shame that the ones supplied in the box aren't rechargeable because the S2 gets through them at quite a rapid pace - especially if you're using the LCD a lot or any of the bracketing options. Another major difference between this camera and the S1 is in storage, with the CompactFlash solution of the previous version replaced with an SD card. This is a shame if you're upgrading from the S1, especially because the 16MB card supplied is next to useless for anything approaching this camera's full ability.

While there's no RAW option available for stills, it's worth having a longer than usual look at the Canon's Movie mode - it's one of the best we've come across on a camera at this kind of price. You can shoot up to 640 x 480-pixels at 30fps for 1GB (or 60 minutes), with stereo sound, and the results really are impressive. There's little in the way of juddering, and the image quality's more than favourable when compared with an affordable solid state camcorder, looking good played back on a reasonably-sized TV screen. You can also capture a still image in the middle of filming, although video is suspended while it's recorded.

With all this power at your command, it's a good thing the resulting images are up to the job, with the S2's ability to render colours worthy of particular praise. Whether it's natural skin tones or the bright hues of a market stall, this Canon's capable of bringing your subject to life with crisp, strong colours. Exposure accuracy is bang on target, with sparkling whites, while the impressive dynamic range leads to lots of visible detail, even in dark shadows.

Considering what this camera's lens is capable of, there's little in the way of either vignetting or barrel distortion on display. Noise is more of a problem, and tends to kick in at around ISO 200, but it doesn't become much of problem until ISO 400, and even then it's usually passable. Detail levels are also high, and the image is sharp, even at the telephoto extremes.

Canon's S2 IS addresses many of the problems that stopped the S1 being close to the top of its class, and while there are a few unresolved issues - the rather plasticky feel, the lack of RAW support, iffy EVF - enough has been done to make this model a much more serious proposition.

It's also caught up with the specifications offered by rivals. Even though the retail price is still slightly steep, the S2 is well worth your consideration if you're on the look out for a compact, lightweight ultra zoom that produces gloriously colourful images. Shaun Martin