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Color Resolution Chart Comparison

Instead of having a single photodetector at each pixel location and then combining the color of neighboring pixels to reproduce the scene color at that pixel location ('demosaicing') the Sigma's Foveon sensor has a multi-layered design which has the equivalent of a red, green and blue photodetector at each pixel location. This means the DP1's sensor 'sees' full color at individual pixel locations. In theory this should mean ultra sharp, detailed images with full color single pixel resolution.

To check if the DP1 can turn this theory into reality we haven taken a series of images of our color resolution chart under controlled conditions in the studio. For the purpose of this specific test we have included the following cameras:

  • Sigma DP1 (Foveon X3 Sensor, 4.7 MP)
  • Nikon D40 (Bayer sensor, 6 MP)
  • Nikon D60 (Bayer sensor, 10 MP)
  • Leica M8 (Bayer sensor, 10 MP)

This test was conducted under our usual condition. Lighting: daylight simulation, >98% CRI. Crops are 100%. Ambient temperature was approximately 22°C (~72°F).

Sigma DP1 (2,534 KB, 4.7 MP) Nikon D40 (2,602 KB; 6.0 MP)
Nikon D60 (3,908 KB; 10.2 MP) Leica M8 (3,079 KB; 10.3 MP)

Sigma DP1 Nikon D40
Nikon D60

Leica M8


Sigma DP1 Nikon D40
Nikon D60 Leica M8

Sigma DP1 Nikon D40
Nikon D60 Leica M8

Sigma DP1 Nikon D40
Nikon D60

Leica M8


Sigma DP1 Nikon D40
Nikon D60

Leica M8


Sigma DP1 Nikon D40
Nikon D60

Leica M8

The DP1 produces a very good resolution (for its pixel count) on our standard black and white resolution test chart but it only becomes apparent on the color test chart how well the camera resolves color detail. The DP1 produces detailed and clean images for all color combinations while the Nikons' Bayer sensor gets visibly confused by some of the color combinations which results in artifacts and blurring. However, like in the black and white scene the D60 and D40 can partially make up for the DP1's better per pixel resolution by simply outputting larger images.

The Leica M8 which has a very light low-pass filter produces clean (but slightly soft) output for some color combinations (light blue/yellow) but fails completely with others such as dark blue/red where it only produces a blurred bar instead of nine distinguishable lines.

In essence, while the per pixel resolution advantage of the DP1 is even more apparent on the color chart, a large proportion of this advantage is being lost simply due to the larger output size of the competition. So what we'd really like to see is a sensor that combines the Foveon's per pixel resolution with the output size of a modern DSLR. It would no doubt take image quality onto another level and beat current Bayer sensors by a mile.

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