Contrast ratio results

Contrast ratio 2241:1 (edge: 36:1)
Monitor model
Submitted 10 Nov 2010 16:05 CET, by 213.226.*.*
Camera model Canon PowerShot A80
Processing remarks

Warning: image file 1: camera was zoomed in too much.
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.
image file 2: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen.
image file 3: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen.
Warning: Image ISO settings are not the same.
Warning: Image F-number settings are not the same.
Warning: Images were taken with different cameras.
Warning: Image focal lengths/zoom levels are not the same.

Black
Screen photo
Luminance 12 cd/m2
Luminance spread 28 cd/m2 (2 standard deviations)
Exposure value –2.85 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 1 x 0.986
Camera settings Exposure time: 1/13   ISO: 400   F-number: 5.6
Focal length: 85.9 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 27001 cd/m2
Luminance spread 70555 cd/m2 (2 standard deviations)
Exposure value –3.32 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.537 x 0.537
Camera settings Exposure time: 1/403   ISO: 1   F-number: 2.8
Focal length: 37.2 mm   (35 mm equivalent)
Exposure compensation: 0
Black at screen edge
Screen photo
Luminance 756 cd/m2
Luminance spread 2453 cd/m2 (2 standard deviations)
Exposure value –3.18 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.409 x 0.401
Camera settings Exposure time: 1/320   ISO: 400   F-number: 10
Focal length: 28.1 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.