SharpCap Forums

Has anyone noticed the image noise in version 2.9? I am using a QHY5LII-C, and the first time I started V2.9 I noticed significant noise on the image, thinking it was something I was doing wrong I spent a considerable amount of time trying to fix it, without success, finally I switched back to V2.8 and, lo and behold no noise. What has happened?

Update: I've just discovered V3.0, just the same noise as 2.9, for me neither 2.9 or 3.0 are useable.

Hi,

could you post a screenshot of the problem so I can see what sort of noise you are getting and also see what values you have for various controls. A pair of screenshots (one for 2.8 and one for 3.0) would be great to compare.

thanks,

Robin

Thanks for your reply.

Ok, I'll do that next time I set the scope up, hopefully next weekend weather permitting.

Hi Robin

I've taken a couple of snapshots but the png file size is too big to attach and I don't want to reduce the quality to jpg. Is there another way to get them to you?

Just an observation; I noticed that with 2.8 the exposure setting has to be a lot higher than with 2.9 and 3.0. In 2.8 if I increase the gain so that the exposure is the same as 2.9/3.0 then the image quality/noise is much the same. So it appears that the issue has something to do with the camera gain setting.

Hi,

sounds like you have tracked down the cause to a higher gain setting, which would be expected to give significantly more noise. I keep the attachment size limited because I don't want to end up with high res astro images needing to be stored on the forums server (and backed up too). Best way to send larger files is you use an alternative image sharing service or a file sharing service like Google drive, DropBox, OneDrive, etc. and share a public link to the files in question.

cheers,

Robin

Hi Robin

I agree it has to be the gain setting, in 2.9/3.0 the minimum gain shows as 1 but is roughly equivalent to maybe 15-20 in 2.8. Anyhow here's a link to the files on drop box.

https://www.dropbox.com/sh/bsued1mls72y ... EAIga?dl=0

Let me know when you have them so I can remove them.

Mike

Ah, now I understand the issue - the gain values have definitely changed between 2.8 and 3.0 - looks like it is down to the QHY SDK (new version) having a bug. I will pass the info on to QHY. Please leave the sample files online for the moment as I will share the link with QHY.

cheers,

Robin

Ok

Hi Robin. Have you finished with the images yet?