Nikon Coolpix 2500 Review: 12. Compared to...: Digital Photography Review

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
Black
Middle Gray	100,101,103	94,93,92	98,98,98	97,98,98
Middle Gray
White	207,208,208	208,209,207	213,213,209	202,204,200
White
Magenta	219,39,123	206,35,81	204,38,112	219,31,83
Magenta
Red	209,32,41	198,30,25	201,30,40	212,17,9
Red
Yellow	209,197,15	217,196,65	206,193,31	187,189,39
Yellow
Green	0,143,55	0,143,94	25,131,63	0,156,77
Green
Cyan	4,161,207	0,155,229	30,155,209	0,186,214
Cyan
Blue	58,47,124	43,39,76	24,30,93	26,41,100
Blue

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 1/100^th 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
	5° 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
	5° Diagonal LPH	800	900
Nikon Coolpix 775	Horiz LPH	750	* 950
	Vert LPH	750	1000
	5° 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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