Contrast ratio results

Contrast ratio 75667:1
Monitor model
Submitted 17 Feb 2010 22:52 CET, by 85.204.*.*
Camera model Canon PowerShot A720 IS
Processing remarks

Warning: image file 1: Underexposed. Please increase the shutter time.
Note: image file 1: suggested exposure time: 52.5 s (Set EV to +1.8)
Warning: image file 2: exposure time below 1/500 sec is unreliable. Try increasing the EV compensation.

Black
Screen photo
Luminance 0.01 cd/m2
Luminance spread 0 cd/m2 (2 standard deviations)
Exposure value –4.31 stops   (aim for –2 to –3)
Exposure spread 0.55 stops
Area used for calculation 0.495 x 0.495
Camera settings Exposure time: 15   ISO: 400   F-number: 2.8
Focal length: 34.3 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 427 cd/m2
Luminance spread 28 cd/m2 (2 standard deviations)
Exposure value –2.29 stops   (aim for –2 to –3)
Exposure spread 0.1 stops
Area used for calculation 0.495 x 0.495
Camera settings Exposure time: 1/1244   ISO: 400   F-number: 2.8
Focal length: 34.3 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.