This year, for the Photokina 2012, Canon decided to refresh its enthusiast photographers compact cameras (Powershot G15 and Powershot S110) with a new 1/1.7″ sensor, and dumped the simple CCD of the G12 and S100, in favor of a warmly welcome backside illuminated CMOS sensor. In addition to the DIGIC 5 DSP processing speed and power, we can expect a quality leap forward. My friends at Focus Numerique, a French website dedicated to digital photography, have already had a Powershot G15 for their review and start with publishing a first batch with images of a studio scene under 200 lux illumination, the G15 being set at 1/4s and f/5.6 for the ISO 80 image. Then ISO setting and shutter speed vary to give us a preview of what to expect at different sensibility settings. They have noticed that the G15 exposure was generally 1/3EV down. I invite you to pay them a visit although the page is in French but the photos speak for themselves and you can display images at 1:1 if you want or even download the full resolution images and RAW files (CR2).
Regarding the JPEG, Renaud, the editor in chief of the photography magazine (probably the tallest photography editor on Earth), states that the G15 between ISO 80 and 400 gives excellent results with a grain structure that remains unnoticeable, fair dynamic range and color reproduction. Only smallest details tend to fade away at ISO 400 but results are pretty good. At ISO 800 as you will see, the noise reduction does its job more intensively but the grainy structure remains very low. But black areas already show some purple pixels. A new threshold is located at ISO 3,200 with a more obvious noise reduction effect that tends to make small details disappearing. DR is very low at ISO 6,400 and at ISO 12,800 will only be worth a 4×6 print in Renaud’s opinion but the result is not so bad.
They have posted other studio scene comparison images taken with competitors like the Panasonic LX7, the Leica X2 and the Samsung EX2F.
Here is the link to this G15 ISO image quality review at Focus Numerique, in French.