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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.

Olympus E-620 (4.1 MB, 12.3 MP) Canon EOS 500D (3.7 MB, 15.1 MP)
Nikon D5000 (2.9 MB; 12.3 MP) Panasonic DMC-G1 (2.9 MB, 10.1 MP)

Olympus E-620 Canon EOS 500D
Nikon D5000 Panasonic DMC-G1

Olympus E-620 Canon EOS 500D
Nikon D5000 Panasonic DMC-G1

Olympus E-620 Canon EOS 500D
Nikon D5000 Panasonic DMC-G1

Measurable results

Camera Measurement
Absolute
resolution
Extinction
resolution
Olympus E-620 Horizontal LPH 2250  * 2650 
Vertical LPH 2250  * 2650 
Nikon D5000 Horizontal LPH 2400  * 3200 
Vertical LPH 2350  * 3200 
Canon EOS 500D Horizontal LPH 2400  * 3200 
Vertical LPH 2350  * 3200 
Panasonic DMC-G1 Horizontal LPH 2600  * 3800 
Vertical LPH 2500  * 3600 

* 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 RAW the differences between the E-620 and its peers opens up even further. We won't make any absolute statements about it because we have been unable to use the same processing software for all the cameras but the distinction between the Panasonic and the Olympus is interesting - their sensors have the same nominal resolution. It's likely that the light sensitive silicon sections are very closely related, even if the color-filter arrays and low-pass filters in front of that and the electronics behind differ. The differences in resolution between the two show very different approaches to the same challenge.

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