Contrast ratio results

Black
Contrast ratio	1:1
Monitor model
Submitted	06 Apr 2019 23:58 CEST, by 35.138..
Camera model	Apple iPhone 7
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 file 3: automatic white balance can cause inaccuracies. image file 3: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen. Warning: image file 3 is too bright to be a dark photo. Maybe you mixed up the files?
Screen photo	[open image]
Luminance	2.92 cd/m2
Luminance spread	1.06 cd/m2 (2 standard deviations)
Exposure value	–1.6 stops (aim for –2 to –3)
Exposure spread	0.53 stops
Area used for calculation	0.404 x 0.404
Camera settings	Exposure time: 1/4 ISO: 125 F-number: 1.8 Focal length: 28 mm (35 mm equivalent) Exposure compensation: 0
White
Screen photo	[open image]
Luminance	2.96 cd/m2
Luminance spread	1.08 cd/m2 (2 standard deviations)
Exposure value	–1.58 stops (aim for –2 to –3)
Exposure spread	0.53 stops
Area used for calculation	0.404 x 0.404
Camera settings	Exposure time: 1/4 ISO: 125 F-number: 1.8 Focal length: 28 mm (35 mm equivalent) Exposure compensation: 0
Black at screen edge
Screen photo	[open image]
Luminance	2.88 cd/m2
Luminance spread	1.07 cd/m2 (2 standard deviations)
Exposure value	–1.62 stops (aim for –2 to –3)
Exposure spread	0.54 stops
Area used for calculation	0.404 x 0.404
Camera settings	Exposure time: 1/4 ISO: 125 F-number: 1.8 Focal length: 28 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.