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Compared to...

Colour Chart Comparison

Using the test charts in our review database we can compare the Nikon Coolpix 2500 to three other 2 megapixel compact digital cameras: Minolta DiMAGE X, Canon Digital IXUS 300 (S300 ELPH) and the Nikon Coolpix 775.

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.

Nikon Coolpix 2500 Minolta DiMAGE X
Canon Digital IXUS 300 (S300 ELPH) Nikon Coolpix 775

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

Patch Nikon
Coolpix 2500
 
Minolta
DiMAGE X
 
Canon Digital
IXUS 300 (S300)
 
Nikon
Coolpix 775
Black 27,27,27 17,18,18 21,21,21 16,20,19
       
Middle Gray 100,101,103 94,93,92 98,98,98 97,98,98
       
White 207,208,208 208,209,207 213,213,209 202,204,200
       
Magenta 219,39,123 206,35,81 204,38,112 219,31,83
       
Red 209,32,41 198,30,25 201,30,40 212,17,9
       
Yellow 209,197,15 217,196,65 206,193,31 187,189,39
       
Green 0,143,55 0,143,94 25,131,63 0,156,77
       
Cyan 4,161,207 0,155,229 30,155,209 0,186,214
       
Blue 58,47,124 43,39,76 24,30,93 26,41,100
       

The Coolpix 2500 produced a very pleasing and accurate colour balance in our tests, notably it has a much lighter black and middle gray than the Coolpix 775. This can also be seen in sample shots which do have better defined and more visible shadow detail.

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.

Horizontal resolution Vertical resolution 5 degree diagonal res.
Nikon Coolpix 2500
Minolta DiMAGE X
Canon Digital IXUS 300 (S300 ELPH)
Nikon Coolpix 775

Measurable findings (three measurements taken for each camera):

Camera Measurement Absolute Res. Extinction Res.
Nikon Coolpix 2500 Horiz LPH 750  * 1000 
Vert LPH 750  1000 
Diagonal LPH 800  900 
Minolta DiMAGE X Horiz LPH 750  * 900 
Vert LPH 700  * 1100 
5° Diagonal LPH 700  900 
Canon Digital IXUS 300 Horiz LPH 820  *1000 
Vert LPH 800  1050 
Diagonal LPH 800  900 
Nikon Coolpix 775 Horiz LPH 750  * 950 
Vert LPH 750  1000 
Diagonal LPH 800  900 

* Moiré is visible

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.

An average performance from Nikon's latest two megapixel Coolpix. We really expected it to have much more resolution than the 775, certainly as much as the Canon Digital IXUS 300 (S300). Unfortunately this wasn't the case. The other very noticeable thing about the 2500's vertical resolution are the clearly visible strong moiré patterns.

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