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Compared to...

Here we can compare, using results from our review archives, the colour reproduction and resolution of the Minolta DiMAGE 7i to three other five megapixel digital cameras: Sony DSC-F707, Nikon Coolpix 5000 and Olympus E-20.

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.

Minolta DiMAGE 7i Sony DSC-F707
Nikon Coolpix 5000 Olympus E-20

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

Minolta
DiMAGE 7i

Sony
DSC-F707

Nikon
Coolpix 5000

Olympus
E-20

Black 28,31,27 18,18,20 19,20,19 31,29,32
Middle Gray 95,97,91 80,89,91 91,91,91 92,92,96
White 221,222,217 176,189,190 209,209,205 201,203,205
Magenta 199,52,104 182,16,82 219,37,93 184,31,102
Red 197,39,45 178,9,4 207,26,23 182,30,43
Yellow 219,206,58 175,180,37 212,189,47 201,193,55
Green 47,140,77 8,135,66 0,130,68 25,125,76
Cyan 54,169,206 12,148,198 1,153,200 26,137,193
Blue 57,55,106 36,21,98 33,44,98 50,34,103

As you can see the DiMAGE 7i has a fairly neutral colour balance with no preference given to any particular colour and fairly mild colour saturation. Remember that if you prefer more vivid colour output you can simply increase the colour saturation setting to +1, +2 or +3.

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.
Minolta DiMAGE 7i
Sony DSC-F707
Nikon Coolpix 5000
Olympus E-20

Measurable findings (three measurements taken for each camera):

Camera Measurement Absolute Res. Extinction Res.
Minolta DiMAGE 7i Horiz LPH * 1300  1450 
Vert LPH * 1150  1450 
5° Diagonal LPH 900 
Sony DSC-F707 Horiz LPH 1450  1800 
Vert LPH 1300  1800 
5° Diagonal LPH + 1000 
Nikon Coolpix 5000 Horiz LPH * 1350  1500 
Vert LPH * 1200  1500 
5° Diagonal LPH + 1000 
Olympus E-20 Horiz LPH * 1350  1650 
Vert LPH * 1300  1650 
5° Diagonal LPH + 1000 

* Moiré becomes visible, + Chart maximum

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.

Not surprisingly the DiMAGE 7i produced identical resolution to the DiMAGE 7. This places it just below the Coolpix 5000 and quite a way away from the DSC-F707 which now seems to be even more remarkable in its ability to make the most from that five megapixel sensor. It's a shame that Minolta didn't use this update as an opportunity to improve image resolution (which is clearly a function of the camera's Bayer interpolation, the lens is good enough).

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