Display and Capture image goes black when green channel reaches saturation on histogram

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NightChaos
Posts: 2
Joined: Thu Apr 11, 2024 6:10 pm

Display and Capture image goes black when green channel reaches saturation on histogram

#1

Post by NightChaos »

This just started in the last couple weeks. I started noticing when I was having difficulty getting stars on the screen for focusing. It does not happen with APT or in ASI Studio, so not cable, USB, or other hardware issues, only happens in Sharpcap. I am using an ASI2600MC pro when this happens. Haven't tested my other cameras yet for this in Sharpcap.

Issue: I increase gain and try to get stars bright enough for focusing and plate solving, but the screen goes nearly signal dark as gain is increased and noise takes over, or screen is black altogether. I did some testing today in daylight conditions to try and replicate. I discovered that as the green channel starts reaching saturation in the histogram the image on screen starts to black out. I'll attach the log, screenshots, and snapshots so you can see what I'm experiencing.

This does not occur in APT or ASI Studio. In those apps the screen and images are saturated white as expected.
Screenshot 2025-01-24 120047.png
Screenshot 2025-01-24 120047.png (672.54 KiB) Viewed 413 times
Screenshot 2025-01-24 120435.png
Screenshot 2025-01-24 120435.png (955.98 KiB) Viewed 413 times
Screenshot 2025-01-24 120555.png
Screenshot 2025-01-24 120555.png (100.48 KiB) Viewed 413 times
Attachments
BugRpt_00003 20_07_32Z_L.CameraSettings.txt
(1.25 KiB) Downloaded 5 times
BugRpt_00002 20_06_54Z_L.CameraSettings.txt
(1.24 KiB) Downloaded 8 times
BugRpt_00001 20_00_01Z_L.CameraSettings.txt
(1.25 KiB) Downloaded 5 times
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Re: Display and Capture image goes black when green channel reaches saturation on histogram

#2

Post by admin »

Hi,

from the camera settings files, I can see that you have the processing option to 'Mask overexposed pixels' turned on. This replaces any overexposed pixels with black and is really designed for things like imaging the corona of the sun in H-alpha - with correct exposure for prominences/corona, the disk will be very overexposed and is distracting, so turning it black is useful.

This setting will have been remembered each time you re-opened the camera as it was turned on at the end of the previous session with the camera and you (presumably) have the option to restore camera settings switched on. You can either turn it off manually (in the pre-processing section of the controls) or hold down CTRL while opening the camera to stop it from restoring the previous settings at all on a one-time basis.

cheers,

Robin
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