QHY128C Gain Question

[admin]

Hi,

Yes, that's the right approach for manually changing the gain on this camera – it won't let you get a sensor analysis out of it though, since SharpCap thinks the actual gain control (the one labelled gain) is the one that it needs to change. I think I can code around this given a little time, but it would be good to know which other camera models need the same fix. I will ask qhy to see if they have a list or a way to find out.

Cheers, Robin

[umasscrew39]

Thanks so much, Robin. Sorry for the hassle about this. The camera seems to produce great full frame images so I am anxious to use it. The ZWO stock of cameras seem to be delayed once again, but due to QC issues, not the COVID-19 problem. However, ZWO seems to make more user friendly cameras out of the box than QHY but that might just be me.

Just one more question: Should I still try a sensor analysis and just based off the labelled gain parameter? Or is it a waste of time?

Regards,
Bruce

[admin]

Hi,

At the moment the sensor analysis would be a waste of time as it would be adjusting the wrong gain control and give a set of results that are either rubbish or only applicable to the particular R/G/B gains that you have set when you run it. I have just emailed QHY and will hopefully get a response from them as to which other cameras might be like your 128C.

Cheers, Robin

[umasscrew39]

Got it.......and thanks again for your help.

Have a safe, great day.

Bruce

[umasscrew39]

Hi Robin

I am curious if you ever heard back from QHY? I should be able to test the camera with the next week.

Bruce

[admin]

Hi Bruce,

Yes, I now have a list of the cameras that are affected by this way of handling the gain – so far the gain works this way on the 128, the 367 and 165.

Long-term, I'd like to make the gain slider in SharpCap the actual analogue gain on the camera, probably the green gain and have the red/blue white balance sliders let you adjust relative gains for the other two channels. However until I understand how the 0 - 4027 gain maps to actual brightness increments, I can't really code that up. So as an interim step I'm going to make the sensor analysis and smart histogram talk to the three white balance adjustments as though they were a single gain control – then if you can get me a sensor analysis using that code I will be able to work out if my long-term plan is viable.

Hoping to get out a new version with this in some time over this weekend.

Cheers, Robin

[3ricJohanson]

Hi there,

I have a QHY128c and have been trying to get the SA process to complete.

It's failing -- from reading this thread it looks like there is a problem with the GAIN control... should I try this via ASCOM or via native QHY?

Best,
-3ric

[admin]

Hi,

if you have the latest version of SharpCap (3.2.6433) then you should see three separate gain controls for your camera for the three colour channels rather than a single gain control. There should also be a digital gain control somewhere elsewhere in the control section. You should also find that the sensor analysis adjusts all three coloured gain controls while it is performing its measurements and leaves digital gain control set at minimum value. If that's happening then at the very least the application is controlling the camera in the way that I would expect

If all of that is working fine on the sensor analysis is still not completing then the best thing to do is to send me the contents of the log after the sensor analysis has failed. This might be quite large, so if it's too big to attach to a post here then you could either zip it up or share it via dropbox or Google Drive or similar.

Cheers, Robin

[3ricJohanson]

Ok, I've updated it and it's running... (via QHY driver)

It does have the three color sliders, and a master "gain" slider.

However, when the SA process is going it doesn't seem to adjust the 3 coloured gain controls, but does adjust the master gain control.

It's still processing -- but made it further than ever before!

I will let you know what happens and post a log regardless.

Best,
-3ric

[admin]

Ok, thanks for the update - if it completes please can you post a screenshot of the results so I can check to see if they make sense.

Robin