Contrast ratio results for iPhone 4

Black
Contrast ratio	488:1
Monitor model	iPhone 4
Submitted	11 Sep 2011 15:31 CEST, by 90.213..
Camera model	Sony DSC-V3
Processing remarks	Note: image file 1: suggested exposure time: 4.6 s (Set EV to -1.1) image file 2: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time. Warning: image file 2: Underexposed. Please increase the shutter time. Note: image file 2: suggested exposure time: 1/110 s (Set EV to +2.2)
Screen photo	[open image]
Luminance	0.06 cd/m2
Luminance spread	0.01 cd/m2 (2 standard deviations)
Exposure value	–1.38 stops (aim for –2 to –3)
Exposure spread	0.27 stops
Area used for calculation	0.49 x 0.49
Camera settings	Exposure time: 10 ISO: 400 F-number: 2.8 Focal length: 33.9 mm (35 mm equivalent) Exposure compensation: 0
White
Screen photo	[open image]
Luminance	31 cd/m2
Luminance spread	12 cd/m2 (2 standard deviations)
Exposure value	–4.73 stops (aim for –2 to –3)
Exposure spread	0.57 stops
Area used for calculation	0.49 x 0.49
Camera settings	Exposure time: 1/500 ISO: 400 F-number: 2.8 Focal length: 33.9 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.