Contrast ratio results

Contrast ratio 4:1
Monitor model
Submitted 01 May 2014 19:40 CEST, by 31.181.*.*
Camera model Canon PowerShot A800
Processing remarks

Warning: image file 1: Underexposed. Please increase the shutter time.
Note: image file 1: suggested exposure time: 1/8 s (Set EV to +5.2)

Black
Screen photo
Luminance 2.9 cd/m2
Luminance spread 1.02 cd/m2 (2 standard deviations)
Exposure value –6.72 stops   (aim for –2 to –3)
Exposure spread 0.51 stops
Area used for calculation 0.539 x 0.539
Camera settings Exposure time: 1/159   ISO: 400   F-number: 3
Focal length: 37.3 mm   (35 mm equivalent)
Exposure compensation: 1
White
Screen photo
Luminance 11 cd/m2
Luminance spread 2 cd/m2 (2 standard deviations)
Exposure value –1.86 stops   (aim for –2 to –3)
Exposure spread 0.25 stops
Area used for calculation 0.539 x 0.539
Camera settings Exposure time: 1/20   ISO: 400   F-number: 3
Focal length: 37.3 mm   (35 mm equivalent)
Exposure compensation: 0

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.