Contrast ratio results

Black
Contrast ratio	5:1
Monitor model
Submitted	03 Sep 2009 08:30 CEST, by 75.117..
Camera model	Canon PowerShot A720 IS
Processing remarks	Warning: image file 1: camera was zoomed in too much. image file 1: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time. Warning: image file 2: camera was zoomed in too much. 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: 1/8 s (Set EV to +1.5) Warning: Image ISO settings are not the same.
Screen photo	[open image]
Luminance	2.94 cd/m2
Luminance spread	7.45 cd/m2 (2 standard deviations)
Exposure value	–2.83 stops (aim for –2 to –3)
Exposure spread	4.25 stops
Area used for calculation	1 x 1
Camera settings	Exposure time: 1/4 ISO: 200 F-number: 3.5 Focal length: 102 mm (35 mm equivalent) Exposure compensation: 0
White
Screen photo	[open image]
Luminance	16 cd/m2
Luminance spread	40 cd/m2 (2 standard deviations)
Exposure value	–4.03 stops (aim for –2 to –3)
Exposure spread	4.25 stops
Area used for calculation	1 x 1
Camera settings	Exposure time: 1/25 ISO: 100 F-number: 3.5 Focal length: 102 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.