Contrast ratio results

Black
Contrast ratio	1455:1
Monitor model
Submitted	21 Apr 2018 06:01 CEST, by 121.136..
Camera model	Apple iPhone 4
Processing remarks	Warning: image file 1: could not determine angle of view; assuming 38 mm lens (35 mm equivalent). 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 2: could not determine angle of view; assuming 38 mm lens (35 mm equivalent). Warning: image file 2: automatic white balance can cause inaccuracies. image file 2: Note: image seems to be noisy. Try reducing the ISO setting or increasing the exposure time. Warning: image file 2: Underexposed. Please increase the shutter time. Note: image file 2: suggested exposure time: 0.4 s (Set EV to +2.5) Warning: image file 3: could not determine angle of view; assuming 38 mm lens (35 mm equivalent). Warning: image file 3: exposure time below 1/500 sec is unreliable. Try increasing the EV compensation. Warning: image file 3: automatic white balance can cause inaccuracies. image file 3: Warning: image includes screen edges or something that's not a monitor. Hold the camera close to the screen. Warning: image file 3: Overexposed. Please decrease the shutter time. Warning: Image ISO settings are not the same. Warning: image file 3 is too bright to be a dark photo. Maybe you mixed up the files?
Screen photo	[open image]
Luminance	0.32 cd/m2
Luminance spread	0.77 cd/m2 (2 standard deviations)
Exposure value	–4.98 stops (aim for –2 to –3)
Exposure spread	4.25 stops
Area used for calculation	0.528 x 0.296
Camera settings	Exposure time: 1/15 ISO: 1000 F-number: 2.8 Focal length: 0 mm (35 mm equivalent) Exposure compensation: 0
White
Screen photo	[open image]
Luminance	462 cd/m2
Luminance spread	386 cd/m2 (2 standard deviations)
Exposure value	–2.64 stops (aim for –2 to –3)
Exposure spread	1.28 stops
Area used for calculation	0.528 x 0.296
Camera settings	Exposure time: 1/343 ISO: 80 F-number: 2.8 Focal length: 0 mm (35 mm equivalent) Exposure compensation: 0
Black at screen edge
Screen photo	[open image]
Luminance	3278 cd/m2
Luminance spread	5730 cd/m2 (2 standard deviations)
Exposure value	–1.41 stops (aim for –2 to –3)
Exposure spread	3.89 stops
Area used for calculation	0.528 x 0.296
Camera settings	Exposure time: 1/1040 ISO: 80 F-number: 2.8 Focal length: 0 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.