Compared to...

The Canon PowerShot A70 and Nikon Coolpix 3100 are both three megapixel, three times optical zoom 'entry level' digital cameras. That said the PowerShot A70 is definitely more feature rich with a better range of manual control compared to the Coolpix 3100. Both are available with a street price of around US$350.

The samples below were taken in Program AE mode to be fair to the Coolpix 3100 which doesn't have an aperture priority mode, normally we would use aperture priority to get optimum sharpness out of the lens. The A70 shot was taken at ISO 50, the Coolpix 3100 at ISO 100, because of the A70's "greater than indicated" sensitivity I believe this to be a fair comparison (if you wish you can download an A70 @ ISO 100 shot below this comparison).

Studio scene comparison

• Canon PowerShot A70: Program AE (P) mode, ISO 50, Default Parameters,
  +0.0 EV compensation, Manual preset white balance
   
• Nikon Coolpix 3100: Manual record mode, Default Parameters,
  +0.0 EV compensation, Manual preset white balance

Canon PowerShot A70	Nikon Coolpix 3100
ISO 50, 1/8 sec, F3.5	ISO 100, 1/5 sec, F3.4
1,332 KB JPEG	926 KB JPEG

Exposure and tonal balance is similar between the two cameras, although as noted previously the Coolpix 3100 delivers a more 'contrasty' image. Color balance is also similar apart from the 3100's treatment of the pink flowers which appears far more vividly than in real life (the A70 was about right on this). Resolution between the two is similar, I'd have to give the edge to the A70. Lens sharpness is another matter, the A70 being much sharper than the 3100, especially near the edges and corners of the frame.

Also available for download

• Canon PowerShot A70 ISO 100 image (1,443 KB)