Contrast ratio results

Contrast ratio 5878:1
Monitor model
Submitted 27 Jan 2011 05:53 CET, by 69.237.*.*
Camera model Canon PowerShot SD870 IS
Processing remarks

Warning: image file 1: automatic white balance can cause inaccuracies.
image file 1: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time.
Warning: image file 1: Underexposed. Please increase the shutter time.
Note: image file 1: suggested exposure time: 17.6 s (Set EV to +7.1)
Warning: image file 2: automatic white balance can cause inaccuracies.
Warning: Image ISO settings are not the same.

Black
Screen photo
Luminance 0.01 cd/m2
Luminance spread 0.01 cd/m2 (2 standard deviations)
Exposure value –9.64 stops   (aim for –2 to –3)
Exposure spread 1.69 stops
Area used for calculation 0.393 x 0.393
Camera settings Exposure time: 1/8   ISO: 800   F-number: 2.8
Focal length: 27.2 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 49 cd/m2
Luminance spread 5 cd/m2 (2 standard deviations)
Exposure value –1.78 stops   (aim for –2 to –3)
Exposure spread 0.16 stops
Area used for calculation 0.393 x 0.393
Camera settings Exposure time: 1/101   ISO: 400   F-number: 2.8
Focal length: 27.2 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.