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Compared to Nikon Coolpix 990 and Olympus C-3030Z
Contd.

Colour Chart Comparison

Shot in daylight, Auto White Balance, EV compensation +0.3 (all cameras), measured light ~10 EV.

Sony DSC-S70
 
Nikon Coolpix 990
 
Olympus C-3030Z
 
 

It's a close run thing. All cameras showing good daylight white balance and good metering. There is little between the three cameras in this test, the S70 producing slightly stronger colours.

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.

  Sony DSC-S70 Coolpix 990 Olympus C-3030Z
 
Patch White 182,182,182 201,201,201 197,197,197
     
Middle Gray 85,85,87 104,104,104 92,92,92
     
Patch Red 189,17,27 223,52,58 191,21,21
     
Patch Green 1,132,35 5,149,63 0,140,52
     
Patch Blue 33,26,123 60,50,112 56,41,102
     

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.

Sony DSC-S70
 
Nikon Coolpix 990
 
Olympus C-3030Z
 

Measurable findings (three measurements taken for each camera):

Camera Measurement Absolute Res. Extinction Res.
Sony DSC-S70 Horiz LPH 1050 1400
Vert LPH 1050 1500
5o Diagonal LPH 1000 n/a
Nikon
Coolpix 990
Horiz LPH 900 1300
Vert LPH 900 1400
5o Diagonal LPH 900 n/a
Olympus
C-3030Z
Horiz LPH 900 1350
Vert LPH 900 1350
5o Diagonal 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.

Well, there you have it. The S70 definitely has more resolution than its nearest competitors the Coolpix 990 and Olympus C-3030Z. Sony have achieved this through the use of a good quality large factor lens system and a quality in-camera processing algorithm.

Red Channel Noise

Not surprisingly the S70 produced very little red channel noise in blue or light blue shades, certainly not as much as we'd seen on the 990 and C-3030Z. 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. That said, this noise can be corrected using third party tools.

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.

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