Contrast ratio results for unknown

Black
Contrast ratio	212:1
Monitor model	unknown
Submitted	05 Dec 2012 03:07 CET, by 206.248..
Camera model	Nikon D40
Processing remarks	image file 1: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen. image file 2: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen. Warning: Image ISO settings are not the same. Warning: Image F-number settings are not the same. Warning: Images were taken with different cameras. Warning: Image focal lengths/zoom levels are not the same.
Screen photo	[open image]
Luminance	7 cd/m2
Luminance spread	12 cd/m2 (2 standard deviations)
Exposure value	–2.16 stops (aim for –2 to –3)
Exposure spread	3.02 stops
Area used for calculation	0.597 x 0.304
Camera settings	Exposure time: 1/10 ISO: 800 F-number: 5.6 Focal length: 29 mm (35 mm equivalent) Exposure compensation: -1
White
Screen photo	[open image]
Luminance	1582 cd/m2
Luminance spread	2796 cd/m2 (2 standard deviations)
Exposure value	–2.08 stops (aim for –2 to –3)
Exposure spread	4.02 stops
Area used for calculation	0.374 x 0.423
Camera settings	Exposure time: 1/250 ISO: 320 F-number: 10 Focal length: 27 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.