Canon Digital IXUS 850 IS

Following the now familiar design of Canon's IXUS series of compact cameras, the IXUS 850 IS is a decent, but not outstanding device. While it does offer good colour representation, it suffers from high chromatic aberration, soft pictures and a few image noise issues.

The sharpness score of 1312 in Imatest is a little below what we expect from a high end, 7.1 megapixel sensor, particularly one from Canon. Our pictures showed some signs of softness and some minor fringing. While this isn't an issue at smaller magnifications, if you're looking to make sizeable enlargements, it may become more visible.

This was exacerbated by the IXUS 850 IS's very high chromatic aberration, for which Imatest awarded it a score of .157%. This is a poor result, with most compacts scoring between .09% and .11%. The effects were clearly visible in our shots in the form of blue and red fringing and prominent haloing. It is most noticeable in area of high contrast, but has an effect across most of the shot, and really detracts from the overall clarity of the pictures.

In our noise test, the results were reasonable. With a score of .88% at ISO 100 in Imatest's noise test, it performed a little worse than some recent models we've seen, but the noise wasn't prolific enough to cause problems. Unless you are looking to make enlargements above 8in x 10in size, then the fine, white noise produced by the IXUS 850 IS won't be an issue.

At higher ISO sensitivities however that isn't the case. Up to ISO 400 the shots remain useable, however at ISO 800 the noise ramps up considerably, and at the highest sensitivity of ISO 1600 it basically blankets the shot. Even at the smallest magnifications, the noise at this level is too much, so we'd recommend staying at lower levels when using the IXUS 850 IS.

Fortunately the IXUS 850 IS's colour performance was considerably better, as it scored just 6.13 in Imatest's colour checker test. Anything below seven is a great result, and our test shots confirmed this. They did show a slight tendency to understaturate reds a little, but this aside, everything was fairly well balanced. Imatest confirmed this, showing minor inaccuracies in the red, and to a lesser extent blue spectrum.

Another area the IXUS 850 IS really impressed was in our speed tests. It has some of the fastest auto-focusing we've ever seen on a compact. From the time you depress the shutter button halfway to the time the photo is ready is often less than a third of a second. It doesn't sound like a huge difference, but you'll quickly notice it when using the camera. Other speed results were equally impressive, with the camera exhibiting a quick .07 seconds of shutter lag, 1.5 seconds between shots and a very impressive 1.1 second power up time. All of these combine to create one of the fastest compacts on the market, and the make the IXUS 850 IS a great choice if you often find yourself caught unaware.

The camera's feature set is fairly standard. It comes equipped with Canon's new face recognition focus technology, which tracks the location of faces in a picture and makes them the focus points. It operates quite well, and should be useful for novice users who regularly take portrait shots.

Focus modes aside, there are the standard white balance presets, along with a custom mode, ten scene modes and ISO sensitivities up to 1600. There is also a standard video recording mode, which captures 640 x 480 movies at up to 30 FPS, and long shutter mode, for low light situations. Also take note of Canon's image stabilisation technology, which helps keep pictures free from handshake, and is particularly useful at the maximum range of the camera's 3x optical zoom. Overall the feature set is more than enough to satisfy the average user and exactly what we expect of a compact camera.

Aesthetically, the IXUS 850 IS is a very sleek device. It follows the standard IXUS design, with a slim, metal exterior that feels solid and rests nicely in the hand. Weighing in at 150g, it is a little heavier than most compact cameras. The controls are well laid out and intuitive to use, with a standard function wheel and directional pad combination bearing the brunt of the work.