Compared to... Canon PowerShot A640

Below you will find a studio comparison between the Canon PowerShot G7 and PowerShot A640 at ISO 800 (the highest setting available on the A640)

Studio scene comparison (@ ISO 800)

  • Canon PowerShot G7: Aperture Priority mode, ISO 800, Default Image Parameters,
    Manual white balance, +0.67 EV compensation
  • Canon PowerShot A640: Aperture Priority mode (F5.0), ISO 80, Default Image Parameters, Manual white balance, +0.7 EV compensation
  • Lighting: Daylight simulation, >98% CRI
Canon PowerShot G7
Canon PowerShot A640
ISO 800, 1/640 sec, F5.0
ISO 800, 1/500 sec, F5.0
4,485 KB JPEG
6,014 KB JPEG

Firstly it's worth pointing out that the G7's ISO 800 result is much much better than its ISO 1600 output (there is also an ISO 3200 option, but this is at a much lower resolution and is only available as a scene mode). Here the difference in noise reduction between the DIGIC III processor (G7) and the older DIGIC II (A640) is much more stark; the G7 output is visibly less noisy and, although the NR artefacts are becoming more obvious, the level of detail retained is roughly the same in both cameras. Again there is a slight sensitivity difference (though it is very small and I wouldn't read too much into it).

Overall, ISO 800 isn't something I'd want to use for anything important (and the effect of the noise reduction on low contrast detail such as hair or foliage is very strong) but I did use it for social snaps indoors in poor light to avoid flash, and - for a 6x4 print - it's not terrible. It is, in fact, a lot better than ISO 400 on many of last year's cameras.