Contrast ratio results

Black
Contrast ratio	629:1
Monitor model
Submitted	13 Oct 2009 03:42 CEST, by 92.200..
Camera model	Canon EOS 450D
Processing remarks	Warning: image file 1: automatic white balance can cause inaccuracies. Note: image file 1: suggested exposure time: 7.0 s (Set EV to +0.1) Warning: image file 2: automatic white balance can cause inaccuracies.
Screen photo	[open image]
Luminance	0.22 cd/m2
Luminance spread	0.01 cd/m2 (2 standard deviations)
Exposure value	–3.64 stops (aim for –2 to –3)
Exposure spread	0.08 stops
Area used for calculation	0.124 x 0.139
Camera settings	Exposure time: 3.2 ISO: 400 F-number: 6.4 Focal length: 8.9 mm (35 mm equivalent) Exposure compensation: -1
White
Screen photo	[open image]
Luminance	138 cd/m2
Luminance spread	4 cd/m2 (2 standard deviations)
Exposure value	–2.65 stops (aim for –2 to –3)
Exposure spread	0.05 stops
Area used for calculation	0.124 x 0.139
Camera settings	Exposure time: 1/99 ISO: 400 F-number: 6.4 Focal length: 8.9 mm (35 mm equivalent) Exposure compensation: -1

The luminance values in cd/m2 are not very reliable, since camera sensitivities can easily differ up to 50% from their nominal value. Typically, the real luminance is 30% lower than this number. The area used for calculation is chosen such that it corresponds to a viewing angle of ±14° horizontally and ±10.5° vertically, which is equivalent to viewing the screen from a distance of about 1.5 times the diagonal size.

Unfortunately, there is a lot of variation in how cameras use EXIF settings. If photos from your camera your produce unusable results, try coming back in a few days. I review submitted pictures regularly and try to fix problems.