Contrast ratio results

Contrast ratio 47096:1
Monitor model
Submitted 20 Nov 2020 22:52 CET, by 31.167.*.*
Camera model Apple iPhone 11
Processing remarks

Warning: image file 1: Underexposed. Please increase the shutter time.
Note: image file 1: suggested exposure time: 49.1 s (Set EV to +5.6)
Warning: image file 2: Overexposed. Please decrease the shutter time.
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 0.01 cd/m2 (2 standard deviations)
Exposure value –8.12 stops   (aim for –2 to –3)
Exposure spread 1.93 stops
Area used for calculation 0.229 x 0.172
Camera settings Exposure time: 1   ISO: 400   F-number: 2.4
Focal length: 14 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 209 cd/m2
Luminance spread 21 cd/m2 (2 standard deviations)
Exposure value –0.41 stops   (aim for –2 to –3)
Exposure spread 0.14 stops
Area used for calculation 0.425 x 0.319
Camera settings Exposure time: 1/401   ISO: 400   F-number: 1.8
Focal length: 26 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.