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Resolution Chart 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 15 equates to 1500 lines per picture height.

Studio light, cameras set to auto, all settings factory default. Aperture selected for optimum sharpness. Exposure compensation +0.7 EV to +1.3 EV. Sigma SD9 image processed with default parameters.

Sigma SD9 Canon EOS-D60
Nikon D100 Fujifilm S2 Pro (6.1 mp size)

Sigma SD9 Canon EOS-D60
Nikon D100 Fujifilm S2 Pro (6.1 mp size)

Sigma SD9 Canon EOS-D60
Nikon D100 Fujifilm S2 Pro (6.1 mp size)

Sigma SD9 Canon EOS-D60
Nikon D100 Fujifilm S2 Pro (6.1 mp size)

Sigma SD9 Canon EOS-D60
Nikon D100 Fujifilm S2 Pro (6.1 mp size)

Measurable findings (three measurements taken for each camera):

Camera Measurement Absolute Res. Extinction Res.
Sigma SD9 Horiz LPH 1550  >2000 
Vert LPH 1550  >2000 
5° Diagonal LPH 1000  n/a 
Canon EOS-D60 Horiz LPH 1600  * 1800 
Vert LPH 1400  1800 
5° Diagonal LPH 1000  n/a 
Nikon D100 Horiz LPH 1600  * 1850 
Vert LPH 1300  * 1700 
5° Diagonal LPH 1000  n/a 
Fujifilm S2 Pro
(6.1 mp size)
Horiz LPH 1650  1900 
Vert LPH 1400  1850 
5° Diagonal LPH 1000  n/a 
Fujifilm S2 Pro
(12 mp size)
Horiz LPH 1800  2000 
Vert LPH 1700  2000 
5° Diagonal LPH 1000  n/a 

* Visible moiré artifacts

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 sensor can
still faithfully record image detail. Beyond the Nyquist frequency aliasing occurs

The SD9 is capable of delivering all nine individual lines of the horizontal or vertical resolution bars up to its maximum absolute resolution (sensor vertical pixel count) and slightly beyond. Note also that because the X3 sensor doesn't need a color filter array it doesn't suffer from color moiré.. Absolute resolution is just less than the Canon EOS-D60, Nikon D100 and Fujifilm S2 Pro (at 6 mp).

However, because the X3 sensor doesn't use a low pass (anti-alias) filter it is able to resolve detail all the way up to Nyquist. Beyond Nyquist the system will alias without any objectionable color moiré. Where a Bayer sensor camera would turn detail beyond Nyquist (such as distant grass texture) into a single plane of blurred color the SD9 will continue to reproduce some individual pixel detail (without color moiré).

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