Sony DSC-P71 Review: 10. Compared to...: Digital Photography Review

Compared to...

Colour Chart Comparison

Using the test charts in our review database we can compare the DSC-P71 to three other 3 megapixel compact digital cameras: Sony DSC-P5, Pentax Optio 330 and Nikon Coolpix 885.

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.


Sony DSC-P71	Sony DSC-P5

Pentax Optio 330	Nikon Coolpix 885

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	Sony DSC-P71	Sony DSC-P5	Pentax Optio 330	Nikon Coolpix 885
Black	20,21,22	20,21,22	10,13,15	34,34,34
Middle Gray	82,86,88	93,98,99	71,80,86	102,102,102
White	183,188,187	197,202,198	179,181,187	197,197,197
Magenta	182,8,141	177,27,124	174,1,89	226,41,94
Red	177,4,53	172,18,36	176,0,21	213,29,25
Yellow	191,184,0	194,188,30	188,174,30	180,188,53
Green	14,146,37	28,142,59	10,119,63	0,151,91
Cyan	6,163,194	29,162,208	0,133,187	22,174,220
Blue	44,24,129	40,28,122	21,22,92	61,51,108

The DSC-P71 exhibits very good colour response with an overall neutral balance and good response to each colour. It also shows very little channel polution in pure colours (little blue in red, little red in blue etc.)

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.

Sony DSC-P71

Sony DSC-P5

Pentax Optio 330

Nikon Coolpix 885

Measurable findings (three measurements taken for each camera):

Camera	Measurement	Absolute Res.	Extinction Res.
Sony DSC-P71	Horiz LPH	1000	1350
	Vert LPH	* 1000	* 1400
	5° Diagonal LPH	900	n/a
Sony DSC-P5	Horiz LPH	1000	1350
	Vert LPH	* 1000	1400
	5° Diagonal LPH	1000	n/a
Kyocera Finecam S3	Horiz LPH	820	* 1100
	Vert LPH	820	* 1050
	5° Diagonal LPH	800	1000
Nikon Coolpix 885	Horiz LPH	* 1000	* 1350
	Vert LPH	950	1350
	5° Diagonal LPH	950	n/a

* 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 overall excellent performance for the DSC-P71, it delivered as much resolution as we could expect of a three megapixel digital camera and continued on past the point of absolute resolution still providing detail.

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