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

Contrast ratio results for Dell

Contrast ratio 950:1 (edge: 549:1)
Monitor model Dell
Submitted 28 Oct 2018 21:37 CET, by 41.169.*.*
Camera model Microsoft Lumia 640 LTE
Processing remarks

Warning: image file 2: Overexposed. Please decrease the shutter time.
image file 3: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time.

Black
Screen photo
[open image]
Luminance 0.12 cd/m2
Luminance spread 0.15 cd/m2 (2 standard deviations)
Exposure value –3.03 stops   (aim for –2 to –3)
Exposure spread 2.34 stops
Area used for calculation 0.398 x 0.529
Camera settings Exposure time: 1.1   ISO: 400   F-number: 2.2
Focal length: 30 mm   (35 mm equivalent)
Exposure compensation: 0
White
Screen photo
[open image]
Luminance 109 cd/m2
Luminance spread 36 cd/m2 (2 standard deviations)
Exposure value –0.48 stops   (aim for –2 to –3)
Exposure spread 0.48 stops
Area used for calculation 0.398 x 0.529
Camera settings Exposure time: 1/147   ISO: 400   F-number: 2.2
Focal length: 30 mm   (35 mm equivalent)
Exposure compensation: 0
Black at screen edge
Screen photo
[open image]
Luminance 0.2 cd/m2
Luminance spread 0.25 cd/m2 (2 standard deviations)
Exposure value –1.89 stops   (aim for –2 to –3)
Exposure spread 2.1 stops
Area used for calculation 0.398 x 0.529
Camera settings Exposure time: 1.4   ISO: 400   F-number: 2.2
Focal length: 30 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.