Previous page Next page


Compared to...

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

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.

Olympus E-20 Sony DSC-F707
Minolta DiMAGE 7 (converted to sRGB) Nikon Coolpix 5000

The green cast we observed on the pre-production F707 has now gone, as well as an overall 'toning down' (reduction in saturation) of all colours (especially red). A far more balanced (if still a little 'bright') colour performance.

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

Olympus
E-20

Sony
DSC-F707

Minolta
DiMAGE 7

Nikon
Coolpix 5000

Black 31,29,32 18,18,20 29,30,32 19,20,19
       
Middle Gray 92,92,96 80,89,91 85,89,97 91,91,91
       
White 201,203,205 176,189,190 220,224,226 209,209,205
       
Magenta 184,31,102 182,16,82 212,40,116 219,37,93
       
Red 182,30,43 178,9,4 208,44,56 207,26,23
       
Yellow 201,193,55 175,180,37 215,221,45 212,189,47
       
Green 25,125,76 8,135,66 26,136,58 0,130,68
       
Cyan 26,137,193 12,148,198 22,144,215 1,153,200
       
Blue 50,34,103 36,21,98 45,31,104 33,44,98
       

As you can see the E-20's colour reproduction (on our simple patches) is remarkably similar to the Sony DSC-F707. There are two major differences (which aren't clear to see on this test):

  • The fact that the E-20 images are far less 'contrasty' than the F707, that is the overall tonal balance is 'flatter' with a better preservation of shadow detail by deliberately maintaining most detail above the black point (this can also make colours appear less saturated).
  • How the E-20 handles 'brighter' colours (more saturated), unlike the F707 the E-20 proved that it didn't "blow out" reds or any other colour which may otherwise affect the F707.

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

Measurable findings (three measurements taken for each camera):

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

Overall the E-20 does well for resolution, a match for the F707 for vertical resolution and very close for horizontal resolution. This goes to show that it is possible to get good resolution from the commonly used five megapixel sensor matched with a good high quality lens and sophisticated image processing algorithms. Compared to the Nikon Coolpix 5000 things are a little closer, it looks as though the E-20's larger slightly higher quality lens manages to squeeze a little more resolution than the 5000.

Some moiré is visible, although not as strong as the DiMAGE 7 it is there and clearly shows that Sony are doing something more advanced with their Bayer interpolation / image processing algorithms to avoid it. Overall the E-20 manages to make far more of its five megapixels than the E-10 did of its four megapixels.

Previous page Next page
11
I own it
2
I want it
29
I had it
Discuss in the forums

Comments