Contrast ratio results

Contrast ratio 184:1
Monitor model
Submitted 30 Nov 2010 15:39 CET, by 91.109.*.*
Camera model Canon EOS 500D
Processing remarks

Warning: image file 1: could not determine angle of view; assuming 38 mm lens (35 mm equivalent).
Warning: image file 1: automatic white balance can cause inaccuracies.
image file 1: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen.
Warning: image file 1: Overexposed. Please decrease the shutter time.
Warning: image file 1: Underexposed. Please increase the shutter time.
Note: image file 1: suggested exposure time: 0.5 s (Set EV to +1.6)
Warning: image file 2: could not determine angle of view; assuming 38 mm lens (35 mm equivalent).
Warning: image file 2: automatic white balance can cause inaccuracies.
image file 2: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen.
Note: image file 2: suggested exposure time: 1/380 s (Set EV to -1.6)

Black
Screen photo
Luminance 0.95 cd/m2
Luminance spread 6.2 cd/m2 (2 standard deviations)
Exposure value –4.05 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.528 x 0.594
Camera settings Exposure time: 1/6   ISO: 400   F-number: 3.5
Focal length: 0 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 174 cd/m2
Luminance spread 117 cd/m2 (2 standard deviations)
Exposure value –0.95 stops   (aim for –2 to –3)
Exposure spread 1.01 stops
Area used for calculation 0.528 x 0.594
Camera settings Exposure time: 1/128   ISO: 400   F-number: 3.5
Focal length: 0 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.