Contrast ratio of ipad air

Contrast ratio 632:1
Monitor model ipad air
Submitted 10 Jul 2016 01:51 CEST, by 206.47.*.*
Camera model Canon EOS REBEL T4i
Processing remarks

Note: image file 1: suggested exposure time: 1.2 s (Set EV to -1.1)

Black
Screen photo
Luminance 0.39 cd/m2
Luminance spread 0.07 cd/m2 (2 standard deviations)
Exposure value –1.38 stops   (aim for –2 to –3)
Exposure spread 0.25 stops
Area used for calculation 0.396 x 0.446
Camera settings Exposure time: 2.6   ISO: 400   F-number: 3.5
Focal length: 28.5 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 244 cd/m2
Luminance spread 74 cd/m2 (2 standard deviations)
Exposure value –2.08 stops   (aim for –2 to –3)
Exposure spread 0.44 stops
Area used for calculation 0.396 x 0.446
Camera settings Exposure time: 1/395   ISO: 400   F-number: 3.5
Focal length: 28.5 mm   (35 mm equivalent)
Exposure compensation: 0
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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.