Resolution Chart Comparison (JPEG)

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.

Canon EOS-1D Mark IV (6.9 16.0 MP) Nikon D3S (2.7 MB; 12.1 MP)
Canon EOS-1D Mark III (3.2 MB, 10.1 MP) Canon EOS 7D (4.8 MB, 17.9 MP)

Canon EOS-1D Mark IV Nikon D3S
Canon EOS-1D Mark III Canon EOS 7D

Canon EOS-1D Mark IV Nikon D3S
Canon EOS-1D Mark III Canon EOS 7D

Canon EOS-1D Mark IV Nikon D3S
Canon EOS-1D Mark III Canon EOS 7D

Measurable results

Camera Measurement
Canon EOS-1D Mark IV Horizontal LPH 2350  * 2800 
Vertical LPH 2400  * 2800 
Nikon D3S Horizontal LPH 2200  2600 
Vertical LPH 2200  * 2600 
Canon EOS-1D Mark III Horizontal LPH * 2100  2400 
Vertical LPH 2050  2350 
Canon EOS 7D Horizontal LPH 2500  * 3100 
Vertical LPH 2450  * 3050 

* Moiré 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)

In this test of outright resolution the 1D Mark IV takes exactly the place you'd expect in this lineup - it shares similar image processing to two of the other cameras here, so both its absolute and extinction resolution figures slot in exactly where you'd expect them to, based simply on pixel count. There are no great surprises or upsets here but it's interesting that it doesn't offer the 26% improvement that raw pixel counting might lead you to expect.