Contrast ratio results

Contrast ratio 2:1
Monitor model
Submitted 23 Nov 2016 17:50 CET, by 73.155.*.*
Camera model Apple iPhone 6s
Processing remarks

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 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.
Warning: Image ISO settings are not the same.

Black
Screen photo
Luminance 23 cd/m2
Luminance spread 64 cd/m2 (2 standard deviations)
Exposure value –2.11 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.419 x 0.419
Camera settings Exposure time: 1/30   ISO: 125   F-number: 2.2
Focal length: 29 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 44 cd/m2
Luminance spread 91 cd/m2 (2 standard deviations)
Exposure value –1.51 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.419 x 0.419
Camera settings Exposure time: 1/30   ISO: 100   F-number: 2.2
Focal length: 29 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.