Contrast ratio results for xt

Contrast ratio 670:1
Monitor model xt
Submitted 16 Dec 2009 05:11 CET, by 69.145.*.*
Camera model Canon PowerShot A620
Processing remarks

Warning: image file 2: exposure time below 1/500 sec is unreliable. Try increasing the EV compensation.
image file 2: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time.

Black
Screen photo
Luminance 0.62 cd/m2
Luminance spread 0.1 cd/m2 (2 standard deviations)
Exposure value –1.77 stops   (aim for –2 to –3)
Exposure spread 0.24 stops
Area used for calculation 0.494 x 0.494
Camera settings Exposure time: 0.8   ISO: 400   F-number: 2.8
Focal length: 34.2 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 413 cd/m2
Luminance spread 179 cd/m2 (2 standard deviations)
Exposure value –2.34 stops   (aim for –2 to –3)
Exposure spread 0.64 stops
Area used for calculation 0.494 x 0.494
Camera settings Exposure time: 1/1244   ISO: 400   F-number: 2.8
Focal length: 34.2 mm   (35 mm equivalent)
Exposure compensation: 0
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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.