Contrast ratio results

Black
Contrast ratio	11023:1
Monitor model
Submitted	22 Feb 2011 23:47 CET, by 81.57..
Camera model	Canon DIGITAL IXUS 850 IS
Processing remarks	Warning: image file 1: automatic white balance can cause inaccuracies. Warning: image file 1: Underexposed. Please increase the shutter time. Note: image file 1: suggested exposure time: 34.0 s (Set EV to +8.1) 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	–10.59 stops (aim for –2 to –3)
Exposure spread	0.94 stops
Area used for calculation	0.393 x 0.393
Camera settings	Exposure time: 1/8 ISO: 243 F-number: 2.8 Focal length: 27.2 mm (35 mm equivalent) Exposure compensation: 0
White
Screen photo	[open image]
Luminance	158 cd/m2
Luminance spread	15 cd/m2 (2 standard deviations)
Exposure value	–1.62 stops (aim for –2 to –3)
Exposure spread	0.13 stops
Area used for calculation	0.393 x 0.393
Camera settings	Exposure time: 1/60 ISO: 83 F-number: 2.8 Focal length: 27.2 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.