Contrast ratio results for Dell u221h

Contrast ratio 1:1
Monitor model Dell u221h
Submitted 06 Jan 2012 06:03 CET, by 96.247.*.*
Camera model Apple iPhone 4S
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: Overexposed. Please decrease the shutter time.
Note: image file 1: suggested exposure time: 1/48 s (Set EV to -1.3)
Warning: image file 2: automatic white balance can cause inaccuracies.
image file 2: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen.
Warning: image file 2: Overexposed. Please decrease the shutter time.
Note: image file 2: suggested exposure time: 1/48 s (Set EV to -1.3)

Black
Screen photo
Luminance 34 cd/m2
Luminance spread 66 cd/m2 (2 standard deviations)
Exposure value –1.23 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.47 x 0.597
Camera settings Exposure time: 1/20   ISO: 125   F-number: 2.4
Focal length: 35 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
Luminance 34 cd/m2
Luminance spread 66 cd/m2 (2 standard deviations)
Exposure value –1.23 stops   (aim for –2 to –3)
Exposure spread 4.25 stops
Area used for calculation 0.47 x 0.597
Camera settings Exposure time: 1/20   ISO: 125   F-number: 2.4
Focal length: 35 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.