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Compared to Nikon Coolpix 990 and Canon S20

In all my reviews I try to present a comparison with other digicams. In these sets of sample images all the cameras were setup in exactly the same manner, had the same subjects, lighting and camera settings (as close as possible). Other Resolution charts and Colour patches now available through the camera comparison database.

Colour Comparison

Shot in daylight, Auto White Balance, EV compensation +0.7 (all cameras), measured light 9 EV.

Olympus C-3030Z
Nikon Coolpix 990
Canon PowerShot S20  

White balance in daylight seems to be sorted for all these cameras (very slight magenta cast on S20), colours defintely much brighter (more saturated) on the Olympus C-3030Z and Nikon Coolpix 990 with the C-3030Z just pipping the 990 for colour accuracy and saturation.

We're only measuring colour here. RGB values below were taken from a VGA reduced image (to average colours and eliminate JPEG artifacts) using the Eyedropper tool in Photoshop with a 5 by 5 Average Sample Size.

  Olympus C-3030Z
Coolpix 990 PowerShot S20
Patch White 197,197,197 201,201,201 204,200,204
Middle Gray 92,92,92 104,104,104 110,108,108
Patch Red 191,21,21 223,52,58 144,25,36
Patch Green 0,140,52 5,149,63 54,120,69
Patch Blue 56,41,102 60,50,112 59,50,111

Dull colours from the S20, something we've seen before (perhaps they'll fix this in a firmware update??)... The Oly producing slightly more pleasing "balanced" colours than the 990.. though it's really to close to call..

Resolution Comparison

Shots here are of the PIMA/ISO 12233 standard resolution test chart (more available for comparison in our comparison database). Studio light, cameras set to auto, Exposure compensation +0.7 EV for all cameras. How to read the charts: All values are 1/100 th lines/picture height/width. So the "10" value equates to 1000.

Olympus C-3030Z
Nikon Coolpix 990
Canon PowerShot S20

Measurable findings (three measurements taken for each camera):

Camera Measurement Absolute Res. Extinction Res.
Horiz LPH 900 1350
Vert LPH 900 1350
5o Diagonal 900 n/a
Coolpix 990
Horiz LPH 900 1300
Vert LPH 900 1400
5o Diagonal LPH 900 n/a
PowerShot S20
Horiz LPH 850 1400
Vert LPH 900 1400
5o Diagonal LPH 900 n/a

Definition of terms:

LPH Lines per Picture Height (to allow for different aspect ratios the measurement is the same for horizontal and vertical)
5o Diagonal Lines set at 5o diagonal
Absolute Resolution Still defined detail (below Nyquist frequency*)
Extinction Resolution Detail beyond camera's definition (becomes a solid gray alias)
n/a Not Available (above the capability of the test chart)
n/v Not Visible (not visible on test results)
* Nyquist frequency defined as the highest spatial frequency where the CCD can still faithfully record
image detail. Beyond the Nyquist frequency aliasing occurs.

Resolution wise there's little between the Olympus C-3030Z and Nikon Coolpix 990, the S20 offers slightly more resolution but does have much more noticeable Moiré (the striped yellow / blue patterns), as does the C-3030Z (compare to the 990). Alias is a phenomenon which exists for all digital cameras, it's an effect of the definition of detail and the Bayer pattern on the CCD (detail beyond the Nyquist frequency). It's down to the internal algorithms in the camera to reduce their effect on the image.

Red Channel Noise

The same red channel nosie we'd seen on the 990 is also apparent on the C-3030Z (not suprising saying they share the same CCD). This noise can be corrected using third party tools and is only visible in SOME shots. The samples above are of 50 x 50 blocks cropped from the colour comparison charts above of the Blue and Cyan patches, each block is then broken down into it's red green and blue channels and reflected as such directly below.

As you can see both the C-3030Z and 990 suffer from more noise (speckling) on the Cyan sample (right hand sample) than the S20. Whether this is down to the CCD, electronics systems, algorithms or JPEG compression it's there in the final image and therefore becomes visible in certain circumstances.

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