At maximum size and quality the G7 produces image files that average around 4.8MB, which means that the G7 employs far less compression than most other 10MP compacts. It means that a gigabyte SD card is enough for approximately 239 shots.
Unfortunately before you’ve filled your gigabyte card, you’ll have to stop to charge the battery. The G7 is equipped with a physically large but surprisingly puny battery, a Li-ion cell of only 720mAh capacity, good for at the most 220 shots. I only managed to get about 170 out of it on its first charge and it is very slow to recharge. This is a bit of a handicap on a camera with semi-pro pretensions, especially since spare batteries are around £40.
Focusing is quick and accurate, with a choice of 9-point AiAF, face detection or flexi-zone, in which the AF point can be positioned anywhere in the frame. Low light focusing is also very effective thanks to a powerful AF lamp with a range of at least four metres.
The G7 features Canon’s superb moving-lens optical image stabilisation, which provides at least two stops of extra hand-held stability.
Image quality is, thankfully, superb. The G7 is equipped with Canon’s latest Digic III image processor, which is both fast and effective. As you’ll see from the sample shots, detail definition is approaching that of a 10MP DSLR. The new lens may be slower than the previous model, but it is nice and sharp right across the frame with virtually no wide-angle distortion. Purple fringing, a big problem on many 10MP compacts, is thankfully well controlled. Image noise, also sometimes a problem for this type of sensor, is also very well controlled. Images are very good at 200 ISO and quite good at 400, although quality does drop off noticeably at higher settings. That said, even at 1600 ISO colour noise is kept to a minimum.
While the lack of RAW mode means that ultimate quality is not attainable, the low compression ratio of the JPEG images means that the G7’s images are as good as you’ll get from a non-SLR camera, certainly significantly better than most other compacts. However there are now several other cameras that compete at this end of the market, and several of them offer advantages over the G7, including longer zoom lenses, better high ISO performance and better battery life. To be fair though, few of them do so in such a compact and attractive style.
While the G7 is unquestionably a superb camera, head and shoulders above anything else at the same size or price, the slower lens, smaller profile and lack of RAW mode will deter many potential buyers from trading in their G6. Instead of the best semi-pro camera on the market, Canon has produced a well specified general purpose camera that will appeal to the more ambitious casual user, rather than as an SLR-alternative for the serious hobbyist.