As a semi-pro camera, the G9 offers a set of features and a level of control second only to a digital SLR, although it doesn't offer much beyond the specification of the G7. It has full manual exposure control, as well as aperture and shutter priority, with an aperture range of f/2.8 to f/8.0, and shutter speeds of 15 to 1/2500th of a second. It has a nine-point AiAF system, as well as a moveable single focus point and face detection in both modes. It has a wide range of pre-set white balance options, as well as two user-defined custom settings, handy if you are shooting in an area with mixed lighting. As well as manual modes it also has program auto, full auto and 16 scene modes, including a couple of unusual ones. The Colour Accent and Colour Swap modes are a lot of fun and can produce some interesting effects. The 3200 ISO mode isn't so useful however, providing an extra stop of sensitivity but only at the 1600 x 1200 (2MP) image size.
The most obvious feature unique to the G9 is the LCD monitor, which is not only quite a bit larger at 3 inches, but also significantly sharper at 230k pixels. Like the G7's screen it has a very wide angle of view, wide enough to view the scene even with the camera held overhead. Like most Canon screens it is very bright and contrasty, and works well in bright daylight thanks to an anti-glare layer. Also like most Canon screens it seems to attract finger marks like a magnet, so you're forever wiping it clean. The G9 also has an optical viewfinder of course, and again this is identical to the one on the G7. It is certainly better than the token viewfinders found on some compact cameras, and does at least have a small reticule for lining up the spot metering and AF points, but it is still quite small, only covers about 75 percent of the frame and suffers quite badly from parallax at close range.
The 12.1-megapixel CCD sensor is, as far as I am aware, the same sensor as the IXUS 960 IS and PowerShot A650 IS compact cameras. It is of the 1/1.7-inch type, physically slightly larger than the 1/2.5-inch sensors used in most compact cameras, but then all of the 12-megapixel cameras I've reviewed so far have used this type of sensor, in fact it's quite possible that it is actually the same sensor, since the manufacturer isn't identified. We'll see in a moment how it fares when combined with a Canon lens and the DIGIC III processor.
The other new feature, or rather the return of a missing feature, is the RAW mode, considered essential by most serious photographers. The G9 uses the same .CR2 file extension as the EOS 30D and EOS 400D digital SLRs, and produces uncompressed RAW files of around 13.5MB, with the option of shooting RAW+JPEG, although this means that a 1GB SD card only holds 47 shots. The G9 comes with Canon's excellent Zoombrowser EX software that includes a RAW processor, allowing a wide range of adjustments, although to get the best out of it you'll be better off with Adobe Camera Raw in Photoshop.