Contrast ratio results

Black
Contrast ratio	251:1
Monitor model
Submitted	13 Nov 2011 18:09 CET, by 84.251..
Camera model	Hewlett-Packard HP PhotoSmart R707 V01.0
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 1: Underexposed. Please increase the shutter time. Note: image file 1: suggested exposure time: 0.3 s (Set EV to +2.2) Warning: image file 2: automatic white balance can cause inaccuracies. image file 2: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time.
Screen photo	[open image]
Luminance	0.93 cd/m2
Luminance spread	2.09 cd/m2 (2 standard deviations)
Exposure value	–4.65 stops (aim for –2 to –3)
Exposure spread	4.25 stops
Area used for calculation	0.563 x 0.563
Camera settings	Exposure time: 1/13 ISO: 400 F-number: 2.9 Focal length: 39 mm (35 mm equivalent) Exposure compensation: 0
White
Screen photo	[open image]
Luminance	233 cd/m2
Luminance spread	34 cd/m2 (2 standard deviations)
Exposure value	–1.39 stops (aim for –2 to –3)
Exposure spread	0.21 stops
Area used for calculation	0.563 x 0.563
Camera settings	Exposure time: 1/340 ISO: 400 F-number: 2.9 Focal length: 39 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.