Frame is dark even though gain and exposure look ok

[crankmosh]

Camera: SV305Pro
Ubuntu 22.04 (patched up to latest)
Mini PC x86

Here is a sample video: https://www.youtube.com/watch?v=t7XKc2_C-ek

Some frames that are grabbed are dark, even though the gain and exposure time seem regular.

[aaronwmorris]

Did you compile indi using the build_indi.sh script or did you have it installed from the repo?

[crankmosh]

repo only has 2.0.4 which doesn't work with svbony so I had to use build_indi.sh, the odd part is, the dark frames still seem to show stars even though they are just really dark

[aaronwmorris]

During your next run, can you check the "Image Lag" view under tools and see if the dark frames are being received in less time than the exposure?

[gigaklatch]

Sounds and looks like the same issue that I have with my SV305M PRO which I use as a guide camera. Every now and then the images are much darker, not fully dark, some of the brigther objects are still seen in the image. This happens both in Astroberry, with INDI driver and in Windows when using the native drivers.

I have spent about a year and a half trying to get SVBony to really look into the issue. But they are very difficult to communicate with and they do not answer any of my questions nor seem to understand me at all and simply suggest to update the drivers. Doing that has not changed anything so far.

So, things are looking dark on this issue.

[aaronwmorris]

If the frames are darker, it means one of two things:

• The camera has reduced the gain behind the scenes
• or the real exposure was much shorter than requested/reported

The exposure being shorter than reported is more likely. An issue I experienced with my SV305 was once you go above 5-6 seconds on exposures, approximately 25% of the frames would require double the time to complete. The exposures were still correct, but the camera spent half the time doing nothing.

This issue was why I started tracking the time it actually takes to get an exposure from a camera in the database. This has helped me diagnose problematic cameras in many cases. You just cannot trust the hardware to do what you tell it to do sometimes.