Resolution Chart Comparison

Shots here are of our '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 set to deliver approximately 80% luminance of white area.

Sony DSLR-A900 (5.3 MB, 24.6 MP) Nikon D700 (3.2 KB; 12 MP)
Canon EOS 5D (3,552 KB; 12.8 MP) Canon EOS-1DS Mark III (4.3 MB, 21 MP)

Sony DSLR-A900

Nikon D700
Canon EOS 5D Canon EOS-1DS Mark III

Sony DSLR-A900 Nikon D700
Canon EOS 5D Canon EOS-1DS Mark III

Sony DSLR-A900 Nikon D700
Canon EOS 5D Canon EOS-1DS Mark III

Measurable results

Camera Measurement
Sony DSLR-A900 Horizontal LPH 2700  3700 
Vertical LPH 2700  3700 
Nikon D700 Horizontal LPH 2200  2600 
Vertical LPH 2200  2650 
Canon EOS 5D Horizontal LPH 2300  2500 
Vertical LPH 2000  2500 
Canon EOS-1Ds
Mark III
Horizontal LPH 2700  3300 
Vertical LPH 2700  3300 

* 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 resolution 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 resolution Detail beyond camera's definition (becomes aliased)

Perhaps unsurprisingly, given it's headline-grabbing 24.6MP pixel count, the Alpha 900 sets a new standard for resolution, edging past the EOS-1Ds Mark III by a whisker, and leaving its 12-ish megapixel competitors in a cloud of dust. Next to the Canon models the output looks soft, but in terms of sheer detail capture it's now the one to beat in the full-frame DSLR market.