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Contrast ratio of Thinkpad X61t

Contrast ratio 856:1
Monitor model Thinkpad X61t
Submitted 16 Nov 2008 22:22 CET, by 76.200.*.*
Camera model Canon PowerShot SD750
Processing remarks

image file 1: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time.
Note: image file 1: suggested exposure time: 0.9 s (Set EV to +1.2)
image file 2: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time.

Black
Screen photo
[open image]
Luminance 0.16 cd/m2
Luminance spread 0.06 cd/m2 (2 standard deviations)
Exposure value –3.68 stops   (aim for –2 to –3)
Exposure spread 0.52 stops
Area used for calculation 0.495 x 0.495
Camera settings Exposure time: 0.4   ISO: 800   F-number: 2.8
Focal length: 34.3 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
[open image]
Luminance 139 cd/m2
Luminance spread 71 cd/m2 (2 standard deviations)
Exposure value –1.59 stops   (aim for –2 to –3)
Exposure spread 0.75 stops
Area used for calculation 0.495 x 0.495
Camera settings Exposure time: 1/501   ISO: 800   F-number: 2.8
Focal length: 34.3 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.