The G12's photo quality is nearly identical to the G11's; still very good overall and excellent for its class.
Lori Grunin
I've been reviewing hardware and software, devising testing methodology and handed out buying advice for what seems like forever; I'm currently absorbed by computers and gaming hardware, but previously spent many years concentrating on cameras. I've also volunteered with a cat rescue for over 15 years doing adoptions, designing marketing materials, managing volunteers and, of course, photographing cats.
The G12's image quality looks great at the lowest ISO sensitivities; you can start to see a slight bit of detail degradation starting at ISO 200 that becomes more overt (along with noisy) at ISO 400. ISO 800 is probably the highest usable setting under the most forgiving circumstances. Picky shooters really won't want to go beyond ISO 200.
2 of 9Matthew Fitzgerald/CNET
G12 vs. G11
The G12's images are nearly identical to the G11's; the slight differences you see here are more attributable to minor discrepancies in the elevation of the tripod head due to the temporal gap in testing.
(1/250 [G12], 1/320 [G11]; f4, center-weighted metering, ISO 400)
3 of 9Lori Grunin/CNET
Raw vs. JPEG, ISO 1600
Processing the G12's files as raw doesn't deliver an unambiguous advantage over the JPEGs. The artifacts and colors are a bit different, and you might be able to gain a little sharpness from the raw, but it doesn't provide any shooting-exposure advantages.
4 of 9Lori Grunin/CNET
Speed
Especially if you're used to shooting with a dSLR, the G12 doesn't feel very fast. But part of that's perception; it's certainly zippy enough to catch animals (this squirrel did not sit still for long).
(1/60 sec, f4.5, ISO 100, evaluative metering)
5 of 9Lori Grunin/CNET
Sharpness
The G12's lens is quite sharp.
6 of 9Lori Grunin/CNET
Distortion
Though it's not terrible, the G12 does display visible barrel distortion at its widest of 28mm.
7 of 9Lori Grunin/CNET
Fringing
The G12 does exhibit a bit of fringing on high-contrast edges, especially close to the edges of the frame.
(1/60 sec, f2.8, ISO 100, evaluative metering)
8 of 9Lori Grunin/CNET
Mid-image detail
This 1:1 crop from the previous photo shows that general shots--wide-angle but not macro--lack the ability to really resolve detail, making the textures look a bit crunchy and digital.
9 of 9Lori Grunin/CNET
Noise and out-of-focus detail, ISO 100
This type of noise/pattern artifact is pretty common with relatively small-sensored models like the G12.