JPEG/RAW Image Size & Quality

The S40 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
• 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	3,130 KB (Canon RAW - .CRW & .THM)
Super Fine JPEG	1,832 KB
Fine JPEG	1,161 KB
Normal JPEG	512 KB
	1600 x 1200
Super Fine JPEG	974 KB
	1024 x 768
Super Fine JPEG	437 KB
	640 x 480
Super Fine JPEG	203 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.

Image Processing Adjustments

The S40 allows for control over three aspects of the cameras internal processing algorithms. You can alter the sharpening, contrast and saturation of images. Although these settings are available in RAW mode they are not applied to the image in-camera but are stored in the RAW image headers as the default settings for the TWAIN acquire module.

Contrast -1	Contrast 0	Contrast +1
Saturation -1	Saturation 0	Saturation +1
Sharpening -1	Sharpening 0	Sharpening +1

As you can see each of these settings changes is relatively subtle, those users who prefer their colours to be bright and vivid straight out of the camera will probably opt for Saturation +1. Those who are more purist will probably leave the Saturation setting alone and use Contrast -1 to maintain as much dynamic range as possible. The S40's Sharpening 0 (Normal) setting is considerably softer than most digital cameras, this is in line with Canon's emerging philosophy of doing as little 'damage' to the image in-camera as possible. If you want your images a little sharper straight out of the camera simply opt for the Sharpening +1 setting.

Colour Effect exposure mode

The S40 has the same new 'Colour Effect' mode which provides four different post-processing colour effects (including black and white). This mode is essentially equivalent to exposure mode 'P' but with the additional post-processing effects.

Colour Effect: Vivid	Colour Effect: Neutral
Colour Effect: Sepia	Colour Effect: Black and White

As you can see the 'Vivid' colour effect gives very strong and vivid colours, these won't be to everyone's taste but could be useful if shooting dull, blue sky dominated or shots only for a computer monitor. The 'Neutral' effect tones colours right down which could be useful for maintaining a wide colour gamut.