Contrast ratio results

Black
Contrast ratio	1:1
Monitor model
Submitted	21 Jul 2011 10:39 CEST, by 121.1..
Camera model	Nikon D90
Processing remarks	Warning: image file 1: automatic white balance can cause inaccuracies. image file 1: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen. Warning: image file 2: automatic white balance can cause inaccuracies. image file 2: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen. Warning: image file 3: camera was zoomed in too much. Warning: image file 3: automatic white balance can cause inaccuracies. image file 3: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen. Warning: Image F-number settings are not the same. Warning: Image focal lengths/zoom levels are not the same. Warning: image file 3 is too bright to be a dark photo. Maybe you mixed up the files?
Screen photo	[open image]
Luminance	3.46 cd/m2
Luminance spread	8.46 cd/m2 (2 standard deviations)
Exposure value	–2.64 stops (aim for –2 to –3)
Exposure spread	4.25 stops
Area used for calculation	0.721 x 0.815
Camera settings	Exposure time: 1/10 ISO: 800 F-number: 4.5 Focal length: 52 mm (35 mm equivalent) Exposure compensation: 0
White
Screen photo	[open image]
Luminance	4.24 cd/m2
Luminance spread	11.77 cd/m2 (2 standard deviations)
Exposure value	–2.92 stops (aim for –2 to –3)
Exposure spread	4.25 stops
Area used for calculation	0.929 x 1
Camera settings	Exposure time: 1/13 ISO: 800 F-number: 4.8 Focal length: 67 mm (35 mm equivalent) Exposure compensation: 0
Black at screen edge
Screen photo	[open image]
Luminance	6 cd/m2
Luminance spread	8 cd/m2 (2 standard deviations)
Exposure value	–2.23 stops (aim for –2 to –3)
Exposure spread	2.69 stops
Area used for calculation	1 x 0.498
Camera settings	Exposure time: 1/8 ISO: 800 F-number: 5.6 Focal length: 52 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.