JPEG or 8-bit TIFF values displayed on a monitor
Feb 3, 2024 10:44:09 #
This is probably not of burning interest to most of you but I'll put it out there in case anyone is curious.
I normally use a white display (RGB=255 255 255) as a target on my calibrated screen while testing for camera performance. It displays a specific constant brightness that I can rely on.
I was curious to see what would happen if I displayed a series of targets from black to white in equal steps (0, 31, 63, 95 ... 223, 255). I measured the displayed values using four different cameras.
The recorded brightness values (signal) agreed very closely. The noise values (standard deviation) varied because the cameras were significantly different.
1. The A7 III is a 24MP full frame camera. I used this as the base result.
2, The A7 II is also 24MP but the Bayer array is gone so I needed to reduce the exposure by one stop. I adjusted the signal/noise ratio for the increase in shutter speed.
3. The Z7 is 45.7 MP so I adjusted signal/noise ratio to make it comparable to 24MP.
4. The X100T is 16MP with a 1.5x crop factor. I adjusted the signal/noise for both differences.
Details are attached to the next post.
I normally use a white display (RGB=255 255 255) as a target on my calibrated screen while testing for camera performance. It displays a specific constant brightness that I can rely on.
I was curious to see what would happen if I displayed a series of targets from black to white in equal steps (0, 31, 63, 95 ... 223, 255). I measured the displayed values using four different cameras.
The recorded brightness values (signal) agreed very closely. The noise values (standard deviation) varied because the cameras were significantly different.
1. The A7 III is a 24MP full frame camera. I used this as the base result.
2, The A7 II is also 24MP but the Bayer array is gone so I needed to reduce the exposure by one stop. I adjusted the signal/noise ratio for the increase in shutter speed.
3. The Z7 is 45.7 MP so I adjusted signal/noise ratio to make it comparable to 24MP.
4. The X100T is 16MP with a 1.5x crop factor. I adjusted the signal/noise for both differences.
Details are attached to the next post.
Feb 3, 2024 10:46:36 #
Results and target images:
Base case
(Download)
Spreadsheet with all of the results
Attached file:
(Download)
Zip file with nine PNG images
Attached file:
(Download)
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