Contrast ratio results

Black
Contrast ratio	2:1
Monitor model
Submitted	27 Nov 2016 17:53 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 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. Note: image file 2: suggested exposure time: 1/61 s (Set EV to -1.6)
Screen photo	[open image]
Luminance	15 cd/m2
Luminance spread	29 cd/m2 (2 standard deviations)
Exposure value	–1.51 stops (aim for –2 to –3)
Exposure spread	4.25 stops
Area used for calculation	0.419 x 0.419
Camera settings	Exposure time: 1/20 ISO: 200 F-number: 2.2 Focal length: 29 mm (35 mm equivalent) Exposure compensation: 0
White
Screen photo	[open image]
Luminance	22 cd/m2
Luminance spread	27 cd/m2 (2 standard deviations)
Exposure value	–0.9 stops (aim for –2 to –3)
Exposure spread	2 stops
Area used for calculation	0.419 x 0.419
Camera settings	Exposure time: 1/20 ISO: 200 F-number: 2.2 Focal length: 29 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.