Contrast ratio | Test results | LCD test | Small-screen tests | Lagom home

Contrast ratio results

Contrast ratio 40:1
Monitor model
Submitted 20 Mar 2009 02:19 CET, by 65.23.*.*
Camera model Canon PowerShot A620
Processing remarks

Warning: image file 1: Overexposed. Please decrease the shutter time.
Note: image file 1: suggested exposure time: 1/4 s (Set EV to -2.1)
Warning: image file 2: Underexposed. Please increase the shutter time.
Note: image file 2: suggested exposure time: 9.6 s (Set EV to +11.9)

Black
Screen photo
[open image]
Luminance 0.03 cd/m2
Luminance spread 0.1 cd/m2 (2 standard deviations)
Exposure value –14.41 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.494 x 0.494
Camera settings Exposure time: 1/403   ISO: 400   F-number: 2.8
Focal length: 34.2 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
[open image]
Luminance 1.25 cd/m2
Luminance spread 0.8 cd/m2 (2 standard deviations)
Exposure value –0.42 stops   (aim for –2 to –3)
Exposure spread 0.95 stops
Area used for calculation 0.494 x 0.494
Camera settings Exposure time: 1   ISO: 400   F-number: 2.8
Focal length: 34.2 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.