Canon PowerShot G12: Video and Image Quality

Video Quality
With 1080p HD video already established in a number of Canon DSLRs and at least one member of the PowerShot family (SD4500 IS), it was a bit surprising to find "only" 720p video in the G12. Well, at least we know what to expect from the G13 in this department. But as 720 HD videos go, the G12 image quality is pretty good. Zoom is available, although the camera will record zoom noise, and the microphone is wind sensitive. There is a wind filter available.

Video capture requires that you set the mode dial to movie, compose the shot, establish focus and shoot. If you recompose the shot focus doesn't change, but exposure will be based on the new composition. It is possible to establish focus on one point and then by zooming or panning onto another point, find that your focus is unacceptable. Subjects at the same general distance as the original focus point will be acceptably sharp, but focus on a distant subject and then pan or zoom to a nearby one (or vice-versa) and you may encounter soft captures.

Image Quality
After shooting the G11 last year, I had high expectations for the G12 and the new camera didn't disappoint. Default images are very good, and there are settings aplenty for folks who shoot the manual modes and want to custom tailor their captures.

The "my colors" color palette will be familiar to Canon users - here are the off (default), vibrant, neutral, sepia and B&W options.

Default (Off)	Vibrant
Neutral	Sepia
Black & White

There are additional options such as positive film, lighter and darker skin tones, vivid blue, green or red and a custom setting to allow you to adjust color to your preference.

The G12 incorporates a couple features to expand the camera's apparent dynamic range. The first is dynamic range correction, which is off by default. In the manual shooting modes with ISO also set manually you have the option of selecting 200 or 400% strength - with auto ISO an auto setting is also available. I didn't notice dramatic changes in setting either strength versus leaving the feature disabled - there was a bit more detail retained in bright areas, particularly at 400%. The downside is that setting 200% involves bumping the ISO to 160 if you have it set lower; at 400% it goes to 320 ISO. If you had ISO set higher than 1600 (and as we'll see later, why would you?) ISO goes to 1600. Here's a shot in aperture priority, and then with 200 and 400% correction.

DRO Off	DRO 200%
DRO 400%

There's also the HDR (high dynamic range) shooting option (for stationary subjects) in the scene menu that's a bit interesting. HDR requires a tripod as it takes 3 images (under, over and correctly exposed) and then merges them to bring out detail from all three in a single image. This is the same basic process used in HDR captures with a DSLR, except those images are then merged in a post processing operation using specialized software. Canon also recommends turning off stabilization when using HDR. I forgot to turn off stabilization in the examples below, but it didn't seem to impact the image. The tripod is mandatory, however - I tried hand holding and also bracing the camera on a rail, but images showed camera shake in both cases. Here's a walkway at the mission shot in aperture priority and again in HDR. Note greater detail and a brighter exposure in the wooden beams overhead in the HDR shot, and also the movement of the branch to the right as a result of three captures being merged into one.

Aperture Priority

HDR

Auto white balance was used for the shots in this review and worked well in most cases - except for shooting fairly warm under incandescent lighting. There are daylight, cloudy, tungsten, fluorescent, fluorescent H, flash, underwater and 2 custom settings available. Somewhat surprising was the lack of a color temperature setting in a $500 camera.

Auto White Balance, 5500k fluorescent light

Evaluative metering was used for image exposure calculation and did a good job overall. As with most compacts there were some instances of lost highlights in high contrast situations, but the G12 performed well on the whole. There are center-weighted and spot options available.

ISO noise performance is what we expected, that is to say, a bit better than your typical compact with smaller sensors and/or more resolution. ISO 80 and 100 are pretty much identical, with 200 showing just the slightest bit of noise and a tiny loss of fine detail - but nothing that would be apparent without the closest scrutiny, and perhaps not even then. ISO 400 shows a bit more noise and loss of fine details, but remains very usable for large prints.

ISO 80	ISO 80, 100% crop
ISO 100	ISO 100, 100% crop
ISO 200	ISO 200, 100% crop
ISO 400	ISO 400, 100% crop
ISO 800	ISO 800, 100% crop
ISO 1600	ISO 1600, 100% crop
ISO 3200	ISO 3200, 100% crop

ISO 800 shows more noise and fine details are becoming smudged, but this is still a small print capable setting. By 1600 images show a marked decline from 800 with increased noise overall and fine details becoming more indistinct. ISO 3200 takes the most dramatic downturn, with significant increased noise over 1600 and fine details that are now reduced to featureless blobs.

Additional Sample Images