Contrast ratio results

Black
Contrast ratio	10892:1
Monitor model
Submitted	04 Apr 2015 19:08 CEST, by 83.61..
Camera model	Apple iPhone 4S
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: 6.3 s (Set EV to +6.6) Warning: image file 2: automatic white balance can cause inaccuracies. Note: image file 2: suggested exposure time: 1/140 s (Set EV to -1.2) Warning: Image ISO settings are not the same.
Screen photo	[open image]
Luminance	0.02 cd/m2
Luminance spread	0.01 cd/m2 (2 standard deviations)
Exposure value	–9.06 stops (aim for –2 to –3)
Exposure spread	1.2 stops
Area used for calculation	0.506 x 0.506
Camera settings	Exposure time: 1/15 ISO: 800 F-number: 2.4 Focal length: 35 mm (35 mm equivalent) Exposure compensation: 0
White
Screen photo	[open image]
Luminance	188 cd/m2
Luminance spread	24 cd/m2 (2 standard deviations)
Exposure value	–1.3 stops (aim for –2 to –3)
Exposure spread	0.18 stops
Area used for calculation	0.506 x 0.506
Camera settings	Exposure time: 1/60 ISO: 64 F-number: 2.4 Focal length: 35 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.