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Compared to... (contd.)

Here we will use our standard color and resolution charts to compare PowerShot S400 to the Canon PowerShot G3, Nikon Coolpix 4500 and Sony DSC-S85.

Colour Chart Comparison

Colour charts are shot in daylight, Auto White Balance, EV compensation +0.3 (all cameras), measured light ~10 EV. This test is also dependent on the accuracy of the camera's auto white balance, the colour charts are shot in daylight but some camera's white balance is better than others. All cameras are given 20 seconds to "settle" before the shot is taken.

Canon PowerShot S400 Canon PowerShot G3
Nikon Coolpix 4500 Sony DSC-S85

In the table below we're only measuring colour. The RGB values were measured from a VGA reduced image (to average colors, remove noise and eliminate JPEG artifacts) using the Eyedropper tool in Photoshop with a 5 by 5 Average Sample Size.

Patch Canon
PowerShot S400

Canon
PowerShot G3

Nikon
Coolpix 4500

Sony
DSC-S85
Black 38,38,38 34,34,34 25,27,27 17,17,19
Middle Gray 107,109,109 102,105,105 101,100,102 76,81,79
White 218,218,213 212,212,212 211,210,209 188,189,189
Magenta 215,44,125 208,45,115 203,38,118 170,12,124
Red 206,38,51 203,34,44 189,22,43 176,0,40
Yellow 212,199,35 208,192,30 193,183,27 181,180,14
Green 22,138,79 23,138,73 29,140,61 24,131,27
Cyan 0,148,219 5,152,218 60,167,205 23,158,175
Blue 34,43,112 37,49,122 54,47,112 23,31,112

As expected the S400's color reproduction was virtually identical to the PowerShot G3, the only differences are in a slightly different metered exposure and moderately 'purer' green color. Compared to the Nikon and the Sony the S400's colors are brighter and seemingly more balanced.

Resolution Comparison

Shots here are of the PIMA/ISO 12233 standard resolution test chart (more of which are available in our comparison database). This resolution chart allows us to measure the actual performance of the lens and sensor system. It measures the ability of the camera to resolve lines at gradually higher resolutions and enables us to provide a definitive value for comparison purposes. Values on the chart are 1/100th lines per picture height. So a value of 8 equates to 800 lines per picture height.

Studio light, cameras set to auto, all settings factory default. Exposure compensation +0.7 EV for all cameras (to compensate for the white background). Click on the camera name below the crops to download the full resolution chart (large JPEG's).

Horizontal resolution Vertical resolution 5 degree diagonal res.
Canon PowerShot S400 (1,384 KB)
Canon PowerShot G3 (1,458 KB)
Nikon Coolpix 4500 (1,327 KB)
Sony DSC-S85 (1,594 KB)

Measurable findings (three measurements taken for each camera)

Camera Measurement Absolute Res. Extinction Res.
Canon PowerShot S400 Horizontal LPH 1250 1400
Vertical LPH 1200 1400
5° Diagonal LPH # 1000 n/a
Canon PowerShot G3 Horizontal LPH 1250 1400
Vertical LPH 1200 1400
5° Diagonal LPH # 1000 n/a
Nikon Coolpix 4500 Horizontal LPH * 1200  * 1350 
Vertical LPH 1100  1300 
5° Diagonal LPH 1000  n/a 
Sony DSC-S85 Horizontal LPH 1250  * 1650 
Vertical LPH 1200  1650 
5° Diagonal LPH 1000  n/a 

* Moiré is visible, + Chart maximum, # Jagged diagonals

Definition of terms

LPH Lines per Picture Height (to allow for different aspect ratios the measurement is the same for horizontal and Vertical)
5° Diagonal Lines set at 5° 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.

The S400 performed very well, delivering the same resolution as its big brother the PowerShot G3. The only difference between the two in resolution performance is nearer to the edges of the frame where the G3 will be sharper. This places the S400 at the top of its class of camera.

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