Contrast ratio results

Contrast ratio 2:1
Monitor model
Submitted 22 Nov 2016 23:03 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 1: Underexposed. Please increase the shutter time.
Note: image file 1: suggested exposure time: 0.9 s (Set EV to +3.7)
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.
Warning: image file 2: Underexposed. Please increase the shutter time.
Note: image file 2: suggested exposure time: 0.6 s (Set EV to +3.1)
Warning: Image ISO settings are not the same.

Black
Screen photo
Luminance 0.26 cd/m2
Luminance spread 0.94 cd/m2 (2 standard deviations)
Exposure value –6.23 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.637 x 0.478
Camera settings Exposure time: 1/15   ISO: 320   F-number: 2.2
Focal length: 39 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 0.52 cd/m2
Luminance spread 3.46 cd/m2 (2 standard deviations)
Exposure value –5.59 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.637 x 0.478
Camera settings Exposure time: 1/15   ISO: 250   F-number: 2.2
Focal length: 39 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.