Contrast ratio results

Contrast ratio 13:1
Monitor model
Submitted 09 May 2018 20:26 CEST, by 94.66.*.*
Camera model Xiaomi Redmi Note 4
Processing remarks

Warning: image file 1: could not determine angle of view; assuming 38 mm lens (35 mm equivalent).
image file 1: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time.
Warning: image file 1: Overexposed. Please decrease the shutter time.
Warning: image file 2: could not determine angle of view; assuming 38 mm lens (35 mm equivalent).
Warning: image file 2: Underexposed. Please increase the shutter time.
Note: image file 2: suggested exposure time: 1/36 s (Set EV to +3.6)

Black
Screen photo
Luminance 1.73 cd/m2
Luminance spread 4.28 cd/m2 (2 standard deviations)
Exposure value –1.5 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.528 x 0.297
Camera settings Exposure time: 0.7   ISO: 100   F-number: 2
Focal length: 0 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 22 cd/m2
Luminance spread 60 cd/m2 (2 standard deviations)
Exposure value –6.05 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.528 x 0.297
Camera settings Exposure time: 1/427   ISO: 100   F-number: 2
Focal length: 0 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.