Resolution Chart Comparison (RAW)

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.

For a (more) level playing field we also convert our resolution tests using Adobe Camera RAW. Because Adobe Camera RAW applies different levels of sharpening to different cameras (this confirmed) we had to use the following workflow for these conversions:

• Load RAW file into Adobe Camera RAW (Auto mode disabled)
• Set Sharpness to 0 (all other settings default)
• Open file to Photoshop
• Apply a Unsharp mask: 80%, Radius 1.0, Threshold 0
• Save as a TIFF (for cropping) and as a JPEG quality 11 for download

Because Adobe Camera Raw doesn't currently render the same level of detail as resolved by the camera's JPEG engine, we've taken the unusual step of using Phase One's Capture One. Again we've minimized sharpening and applied the same unsharp mask in Photoshop.

Sigma DP2 (2.3 MB, 4.69x3 MP)	Olympus E-P1 (5.4 MB, 12.3 MP)
Ricoh GRD III (3.3 MB; 10.0 MP)	Sony DSLR A330 (2.5 MB, 10.2 MP)

Sigma DP2	Olympus E-P1
Ricoh GRD III	Sony DSLR A330

Sigma DP2	Olympus E-P1
Ricoh GRD III	Sony DSLR A330

Sigma DP2	Olympus E-P1
Ricoh GRD III	Sony DSLR A330

Measurable results

ACR does little to pull more resolution out of the RAW files, which suggests the camera's JPEG engine is doing a reasonable job. Given that the JPEG is representing detail well beyond Nyquist (the theoretical maximum), it's no surprise that there's little more to be gained in RAW.