Contrast ratio results

Contrast ratio 1536:1 (edge: 3571:1)
Monitor model
Submitted 23 Aug 2008 07:39 CEST, by 24.67.*.*
Camera model Canon PowerShot A460
Processing remarks

Warning: image file 1: Underexposed. Please increase the shutter time.
Note: image file 1: suggested exposure time: 93.3 s (Set EV to +8.5)
Warning: image file 2: camera was zoomed in too much.
Warning: image file 2: Underexposed. Please increase the shutter time.
Note: image file 2: suggested exposure time: 1/6 s (Set EV to +0.6)
Warning: image file 3: Underexposed. Please increase the shutter time.
Note: image file 3: suggested exposure time: 217.0 s (Set EV to +9.8)
Warning: Image F-number settings are not the same.
Warning: Image focal lengths/zoom levels are not the same.

Black
Screen photo
Luminance 0 cd/m2
Luminance spread 0 cd/m2 (2 standard deviations)
Exposure value –9.04 stops   (aim for –2 to –3)
Exposure spread 0.97 stops
Area used for calculation 0.534 x 0.534
Camera settings Exposure time: 1   ISO: 400   F-number: 2.8
Focal length: 37 mm   (35 mm equivalent)
Exposure compensation: 2
White
Screen photo
Luminance 4.88 cd/m2
Luminance spread 3.75 cd/m2 (2 standard deviations)
Exposure value –5.15 stops   (aim for –2 to –3)
Exposure spread 1.17 stops
Area used for calculation 1 x 1
Camera settings Exposure time: 1/40   ISO: 400   F-number: 4.5
Focal length: 98.7 mm   (35 mm equivalent)
Exposure compensation: -2
Black at screen edge
Screen photo
Luminance 0 cd/m2
Luminance spread 0 cd/m2 (2 standard deviations)
Exposure value –10.26 stops   (aim for –2 to –3)
Exposure spread 1.43 stops
Area used for calculation 0.534 x 0.534
Camera settings Exposure time: 1   ISO: 400   F-number: 2.8
Focal length: 37 mm   (35 mm equivalent)
Exposure compensation: 2

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.