Contrast ratio results

Contrast ratio 931:1
Monitor model
Submitted 19 Apr 2009 11:44 CEST, by 85.186.*.*
Camera model Canon PowerShot A570 IS
Processing remarks

image file 1: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time.
Note: image file 1: suggested exposure time: 1.7 s (Set EV to +1.5)

Black
Screen photo
Luminance 0.15 cd/m2
Luminance spread 0.04 cd/m2 (2 standard deviations)
Exposure value –3.98 stops   (aim for –2 to –3)
Exposure spread 0.41 stops
Area used for calculation 0.495 x 0.495
Camera settings Exposure time: 0.6   ISO: 400   F-number: 2.6
Focal length: 34.3 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 142 cd/m2
Luminance spread 62 cd/m2 (2 standard deviations)
Exposure value –1.7 stops   (aim for –2 to –3)
Exposure spread 0.64 stops
Area used for calculation 0.495 x 0.495
Camera settings Exposure time: 1/318   ISO: 400   F-number: 2.6
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.