Contrast ratio results

Contrast ratio 2:1
Monitor model
Submitted 18 Nov 2016 04:44 CET, by 107.77.*.*
Camera model Apple iPhone 5c
Processing remarks

Warning: image file 1: automatic white balance can cause inaccuracies.
image file 1: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time.
Note: image file 1: suggested exposure time: 1/6 s (Set EV to +1.2)
Warning: image file 2: automatic white balance can cause inaccuracies.
image file 2: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time.
Note: image file 2: suggested exposure time: 1/7 s (Set EV to +1.2)
Warning: Image ISO settings are not the same.

Black
Screen photo
Luminance 0.4 cd/m2
Luminance spread 0.36 cd/m2 (2 standard deviations)
Exposure value –3.72 stops   (aim for –2 to –3)
Exposure spread 1.42 stops
Area used for calculation 0.477 x 0.477
Camera settings Exposure time: 1/17   ISO: 1600   F-number: 2.4
Focal length: 33 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 0.72 cd/m2
Luminance spread 2.36 cd/m2 (2 standard deviations)
Exposure value –3.68 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.477 x 0.477
Camera settings Exposure time: 1/15   ISO: 800   F-number: 2.4
Focal length: 33 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.