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JPEG/RAW Image Size & Quality

The G2 provides four image size options in combination with three JPEG quality settings. On top of this you have the uncompressed, unprocessed RAW file which is simply a pixel by pixel readout of the CCD (10-bits per pixel).


Standard Test Scene

To give an impression of what some of the combinations of image size and quality produce the table below is a cross reference of some of them:

  • 2272 x 1704 RAW
  • 2272 x 1704 Super-Fine
  • 2272 x 1704 Fine
  • 2272 x 1704 Normal
  • 1600 x 1200 Super-Fine
  • 1600 x 1200 Fine
  • 1024 x 768 Super-Fine
  • 640 x 480 Super-Fine

Images below are cropped 240 x 100 area of the image magnified 200% (nearest neighbour).


 
2272 x 1704
RAW
3,200 KB (Canon RAW - .CRW)
Super
Fine
JPEG

2,129 KB
Fine
JPEG

1,317 KB
Normal
JPEG

614 KB
 

 
1600 x 1200
Super
Fine
JPEG

1,117 KB
Fine
JPEG

698 KB
 

 
1024 x 768

Super
Fine
JPEG


479 KB
 

 
640 x 480

Super
Fine
JPEG


215 KB

Clearly Super-Fine JPEG provides a high quality image with virtually no visible artifacts. Moving down to Fine and we can just about make out the beginnings of some JPEG artifacts but they're pretty few and far between, this setting would probably be the best trade off between quality and storage space.


ISO (Sensitivity) Adjustment

ISO equivalence on a digital camera is the ability to increase the sensitivity of the CCD to allow for faster shutter speeds and/or better performance in low light. The way this works in a digital camera is by "turning up the volume" on the CCD's signal amplifiers, nothing is without its price however and doing so also amplifies any noise that may be present and often affects colour saturation.

The G2 features four selectable ISO sensitivities of 50, 100, 200 and 400 as well as the same Auto mode we saw on the G1 (which varies sensitivity between ISO 50 and 100 depending on available light).

Good light (10 EV) Low light (3 EV)
ISO 50 ISO 50
ISO 100 ISO 100
ISO 200 ISO 200
ISO 400 ISO 400

As we'd expect the G2's ISO 50 appears very clean, there's just the hint of some noise but nothing visible. ISO 100 does increase the noise levels slightly, they appear as coloured mottle and dark/light texture highlights. ISO 200 is usable, ISO 400 seems to me to be a little too noisy to be useful at full resolution (though obviously if you were to sample this image down in size some of the noise would average out).

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