Contrast ratio results

Contrast ratio 2:1
Monitor model
Submitted 29 Oct 2015 17:36 CET, by 85.228.*.*
Camera model Canon PowerShot S100
Processing remarks

Warning: using the flash makes no sense.
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.
Note: image file 1: suggested exposure time: 1/58 s (Set EV to -1.5)
Warning: image file 2: automatic white balance can cause inaccuracies.
image file 2: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen.
Note: image file 2: suggested exposure time: 1/160 s (Set EV to -1.4)
Warning: Image ISO settings are not the same.

Black
Screen photo
Luminance 6 cd/m2
Luminance spread 5 cd/m2 (2 standard deviations)
Exposure value –0.96 stops   (aim for –2 to –3)
Exposure spread 1.42 stops
Area used for calculation 0.35 x 0.35
Camera settings Exposure time: 1/20   ISO: 640   F-number: 2
Focal length: 24.2 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 12 cd/m2
Luminance spread 4 cd/m2 (2 standard deviations)
Exposure value –1.05 stops   (aim for –2 to –3)
Exposure spread 0.51 stops
Area used for calculation 0.466 x 0.262
Camera settings Exposure time: 1/60   ISO: 800   F-number: 2
Focal length: 24.2 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.