Contrast ratio results

Black
Contrast ratio	2:1
Monitor model
Submitted	23 Apr 2014 21:55 CEST, by 83.23..
Camera model	Canon PowerShot A530
Processing remarks	Note: image file 2: suggested exposure time: 1/210 s (Set EV to -1.0) Warning: Image ISO settings are not the same. Warning: Image F-number settings are not the same. Warning: Image focal lengths/zoom levels are not the same.
Screen photo	[open image]
Luminance	93 cd/m2
Luminance spread	34 cd/m2 (2 standard deviations)
Exposure value	–1.82 stops (aim for –2 to –3)
Exposure spread	0.54 stops
Area used for calculation	0.841 x 0.841
Camera settings	Exposure time: 1/125 ISO: 400 F-number: 3.5 Focal length: 58.2 mm (35 mm equivalent) Exposure compensation: 0
White
Screen photo	[open image]
Luminance	213 cd/m2
Luminance spread	25 cd/m2 (2 standard deviations)
Exposure value	–1.46 stops (aim for –2 to –3)
Exposure spread	0.17 stops
Area used for calculation	0.497 x 0.497
Camera settings	Exposure time: 1/101 ISO: 100 F-number: 2.6 Focal length: 34.4 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.