Resolution Chart Comparison

Shots here are of our new 'version two' resolution chart which provides for measurement of resolution up to 4000 LPH (Lines Per Picture Height). A value of 20 equates to 2000 lines per picture height. For each camera the relevant prime lens was used. The chart is shot at a full range of apertures and the sharpest image selected. Studio light, cameras set to aperture priority (optimum aperture selected), image parameters default. Exposure compensation +0.7 EV to +1.3 EV (depending on the camera).

Pentax K10D (2,271 KB; 10 MP) Nikon D80 (2,769 KB; 10 MP)
Sony Alpha DSLR-A100 (2,213 KB; 10 MP) Canon EOS 30D (2,409 KB; 8.2 MP)

Pentax K10D Nikon D80
Sony Alpha DSLR-A100 Canon EOS 30D (8 MP)

Pentax K10D Nikon D80
Sony Alpha DSLR-A100 Canon EOS 30D (8 MP)

Pentax K10D Nikon D80
Sony Alpha DSLR-A100 Canon EOS 30D (8 MP)

Measurable findings (three measurements taken for each camera):

Camera Measurement
Pentax K10D Horizontal LPH * 2000  * 2300 
Vertical LPH 1800  * 2500 
Nikon D80 Horizontal LPH 2200  2300 
Vertical LPH 1800  2300 
Sony Alpha DSLR-A100 Horizontal LPH * 2200  2900 
Vertical LPH * 1800  2800 
Canon EOS 30D Horizontal LPH 1850  2100 
Vertical LPH 1650  2100 

* Moire is visible
+ Chart maximum
LPH Lines per Picture Height (to allow for different aspect ratios the measurement is the same for horizontal and vertical)
Absolute res. Point at which all lines of a resolution bar are still visible and defined, beyond this resolution loss of detail occurs (below Nyquist frequency).
Extinction res. Detail beyond camera's definition (becomes aliased)

Not that surprising to see the K10D under performing in our resolution chart shot, this due primarily to the already discussed lack of sharpness in edge detail (be this due to poor demosaicing or unusual sharpening). Overall the biggest difference (versus the competition) is in the horizontal direction. A RAW converted resolution chart exhibits about 2200 LPH in the horizontal direction and 2000 LPH in the vertical direction.