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.

Pentax K-x (5.2 MB, 12.3 MP) Canon EOS 500D (4.4MB, 15.1 MP)
Nikon D5000 (3.5 MB; 12.3 MP) Olympus E-620 (6.4 MB, 12.3 MP)

Pentax K-x Canon EOS 500D
Nikon D5000 Olympus E-620

Pentax K-x Canon EOS 500D
Nikon D5000 Olympus E-620

Pentax K-x Canon EOS 500D
Nikon D5000 Olympus E-620

Measurable results

Camera Measurement
Pentax K-x Horizontal LPH 2200  * 2650 
Vertical LPH 2200  * 2650 
Canon EOS 500D Horizontal LPH 2350  * 2800 
Vertical LPH 2300  * 2650 
Nikon D5000 Horizontal LPH 2200  2650 
Vertical LPH 2100  2600 
Olympus E-620 Horizontal LPH 2250  2550 
Vertical LPH 2200  2500 

* 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)

The K-x does quite well in this test. It can't quite keep up with the EOS 500D's higher nominal resolution but is on par with the Nikon D5000 and the Olympus. At higher frequencies the Pentax shows some signs of moiré. The Canon produces not only the highest resolution but also the cleanest image in this comparison. When looking at these image results please bear in mind that they, like in all our studio tests, have been achieved with stopped down prime lenses. You won't get the same resolution out of the cameras' kit lenses.