Contrast ratio results

Black
Contrast ratio	9896:1
Monitor model
Submitted	17 Jan 2014 13:23 CET, by 37.78..
Camera model	Apple iPad mini
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. Warning: image file 1: Underexposed. Please increase the shutter time. Note: image file 1: suggested exposure time: 13.0 s (Set EV to +7.6) Warning: image file 2: automatic white balance can cause inaccuracies. Warning: Image ISO settings are not the same.
Screen photo	[open image]
Luminance	0.01 cd/m2
Luminance spread	0.01 cd/m2 (2 standard deviations)
Exposure value	–10.11 stops (aim for –2 to –3)
Exposure spread	1.42 stops
Area used for calculation	0.476 x 0.478
Camera settings	Exposure time: 1/15 ISO: 640 F-number: 2.4 Focal length: 33 mm (35 mm equivalent) Exposure compensation: 0
White
Screen photo	[open image]
Luminance	104 cd/m2
Luminance spread	9 cd/m2 (2 standard deviations)
Exposure value	–1.51 stops (aim for –2 to –3)
Exposure spread	0.13 stops
Area used for calculation	0.476 x 0.478
Camera settings	Exposure time: 1/24 ISO: 40 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.