QHY247c border shading only in Sharpcap

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BillGriz57
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Joined: Thu Jul 02, 2020 7:58 pm

QHY247c border shading only in Sharpcap

#1

Post by BillGriz57 »

I started using Sharpcap a few months back with my relatively new QHY247c. I was getting a lot of shading around the borders that were making processing difficult. I started using N.I.N.A for the lights and then Sharpcap afterwards for the calibration images. Shading appeared to be worse. After doublechecking my exposure time/gain/offset and temps, I ran a new set of calibration images using EZ-Cap that comes with the camera. No shading. After doing a number of tests I've determined that this shading is being caused by Sharpcap....or rather a setting I probably have wrong.
If I stack lights (no darks, flats, or anything else) acquired with SC, there is considerable shading around the borders and reduced contrast in the stack.
Lights acquired (again, nothing else) with N.I.N.A. do not have this shading. If I try to use darks acquired with SC to calibrate these images, shading is back. Some images, magenta, some are green.
Tried forcing different Bayer patterns and Amp noise reduction on and off just to see if it changed anything. It didn't.
I've attached images and fits info. Exposure has been increased on all images only. no other processing.
Any assistance appreciated.
Thanks,
SC Cone Lights only
SC Cone Lights only
Cone-lightsonly-St.jpg (409.63 KiB) Viewed 2254 times
Bill G.
Attachments
SC-Fits-Info.txt
SC Fits Info
(768 Bytes) Downloaded 79 times
NINA Fits Info.txt
NINA Fits Info
(2.34 KiB) Downloaded 74 times
N.I.N.A Triplet, EZ-Cap Darks
N.I.N.A Triplet, EZ-Cap Darks
Test-w_ezcap-St.jpg (222.54 KiB) Viewed 2254 times
N.I.N.A Triplet, SharpCap Darks
N.I.N.A Triplet, SharpCap Darks
NoiseRed-off-St.jpg (122.89 KiB) Viewed 2254 times
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Re: QHY247c border shading only in Sharpcap

#2

Post by admin »

Hi,

looking at the settings you are using in SharpCap, some of them seem a little odd

Code: Select all

White Bal (B)=2
White Bal (G)=1
White Bal (R)=1
Gamma=1.12
Setting gamma to anything other than 1.00 applies a non-linear stretch to the image before it gets to SharpCap - that's a bad thing for deep sky imaging (but can be useful for solar in some circumstances). I'd set that back to 1.00

The white balance values are also worrying me a bit - unfortunately 'neutral' white balance values vary from camera to camera for QHY, but I'd expect either 16 or 64 to be neutral. Again, it's best to set all these colour balance values to the neutral value (all the same) to ensure you get data from the camera that hasn't been adjusted by these controls. You should use the same settings for dark frames as for light frames.

The trick to work out the neutral colour balance settings is to set up a deliberately over exposed image and then show the histogram.
Capture.JPG
Capture.JPG (39.23 KiB) Viewed 2250 times
This is what my histogram looks like if I use your white balance values on my QHY294 - that's as far right as I can get my histogram peaks no matter how much I turn up gain/exposure.

Now to get the correct 'neutral' white balance values, turn up each white balance control a little at a time until the over exposed histogram peak gets to the right hand side of the graph. For me the appropriate values are 16 for each channel, but yours may vary.

Hopefully getting those settings back to 'normal' will help.

Robin
BillGriz57
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Joined: Thu Jul 02, 2020 7:58 pm

Re: QHY247c border shading only in Sharpcap

#3

Post by BillGriz57 »

Thank you! I figured I was doing something wrong.....however, this brings up questions.

I had not paid attention to these because I did not think they were applied to the image file and only to the display. I guess I'm still thinking in DSLR mode.
1. "an overexposed image" sounds a bit arbitrary. I assume "not" saturated. The amount of overexposure appears to affect the setting....but I tried doing this with a flat panel image...non-saturated. Ran up around 16 and that put me to the right. Blue channel was still a bit low, I think it ended up around 19. Also had to shift my offset back down as this pushed my dark frame levels up.
2. " You should use the same settings for dark frames as for light frames". How do I know?? I don't see FITS info for gamma or white balance on the other two capture programs. I also don't see any way to change them.

I would prefer to use Sharpcap to get my calibration frames (among other types of captures) but prefer NINA for my sequences. Without any way to see or match up settings, I'm not sure that is a good idea. I will crate some darks with the new WB and gamma at 1.0 ad see what the image looks like when the darks are used to calibrate.
Thanks for the quick response!
Bill G.
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Re: QHY247c border shading only in Sharpcap

#4

Post by admin »

Hi,

I'd hope that if NINA etc are not showing controls like gamma or white balance then they are using the default values, but it's hard to be sure as you say.

As a rule of thumb, anything you adjust in the right hand panel will affect the saved images with the exception of the 'Display Histogram Stretch' adjustments.

cheers,

Robin
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Re: QHY247c border shading only in Sharpcap

#5

Post by couchcaptain »

Hi!
I'm new here too, and it's not only border shading, but the Native driver for QHY183C also showing border glow. I tried this in all 32bit/62bit Sharpcap and it's also there in Sharpcap 4.0
It's pretty much useless to do live stacking with this camera this way, because the glow overpowers the flats and darks and ruins the image.
This glow does not show up in any other imaging software (APT/N.I.N.A) , also doesn't show if I switch to ASCOM driver in Sharpcap. It's definetely a driver issue. I have followed some post in Cloudynights, the last person who had this issue claimed he resolved it, but mine doesn't go away. I tried uninstalling/reinstalling, unplugging/replugging, all the settings that I can think of, the border glow doesn't go away. It gets very intensified by stretching the image or live stacking and it disregards any gain or offset. It has nothing to do with what telescope or reducer used either, because I can also reproduce this by just having the camera next to my PC and no telescope attached.
Again:
1. Only with the native drivers for Sharpcap
2. ASCOM drivers don't have this issue
3. None of the other astrophotography software shows (native drivers or not) this issue.
Also note the extra peaks in the histogram, those aren't present anywhere else.
With ASCOM (QHYCapture)
https://ibb.co/H4kDfrN
With Native driver:
https://ibb.co/jf2nXJT

Relevant thread in Cloudynights, not sure if the person really fixed it, because I tried everything possible:
https://www.cloudynights.com/topic/7183 ... bars-issue

Livestacked image with flat applied (the border glow turns purple)
https://www.cloudynights.com/uploads/mo ... _thumb.jpg
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Re: QHY247c border shading only in Sharpcap

#6

Post by admin »

Hi,

Ok, another thing to try...

By default, SharpCap will run cameras in video mode (since it started out as a webcam capture application). Maybe this causes the glow on the images.

You can put SharpCap into still mode though - the best way to do this is to use the latest SharpCap 4.0, then unselect the 'Live View' option at the left of the toolbar before opening the camera. In this mode, SharpCap will only take images when you press the 'snapshot' or 'framing shot' buttons. See if that helps.

If you are using live stacking, SharpCap will automatically re-enable live view, but there is also a 'Force Still Mode' control, which you can set to on that makes live view use the still frame capture section of the SDK.

Don't try in SharpCap 3.2 - there were a number of bugs in using the still frame capture SDK for QHY cameras in 3.2 that are fixed in 4.0

Robin
couchcaptain
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Re: QHY247c border shading only in Sharpcap

#7

Post by couchcaptain »

Thank you for the advice, I'm pretty sure it's a QHY "exclusive" :lol: , since I don't have any similar issues using my ZWO camera. By the way, I find Sharpcap essential for any astrophotographer and it's always my go-to software- before I begin imaging, to do test runs with various gains as well as it is what I use for polar alignment.
My latest was to prove someone, that I can live stack rosetta nebula via Sharpcap on my older alt-az mount and looks pretty decent, considering that i had to crop off the rotating corners. :mrgreen:
Alessandro
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Joined: Sun Nov 07, 2021 7:27 pm

Re: QHY247c border shading only in Sharpcap

#8

Post by Alessandro »

Hello.

I'm new to this Sharpcap forum,
so maybe I will write in the wrong section or reply to the wrong post..
Anyway, I have experienced many problems with ampglow issues,
using a QHY183c camera with Sharpcap that I have reduced with many attempts, but never completely.
I'm talking right about the top and bottom bars (border shading).
I have seen the suggestions, about downloading the 4.0 version
of Sharpcap and the "still mode" to activate in order to reduce the problem.
The version I was using all the time is the 3.2 (64bit).
Now I 've just downloaded the 4.0 (64bit) and launch it.
I have noticed that the "amp noise reduction" feature/function is not anymore available.
Is that a mistake to solve, or is that intentionally removed?
I simply need to be sure that this feature is set to "ON"
or differently that the program corrects the strong AMP glow/noise automatically by itself.
Many thanks in advance to the administrator ..
Alessandro
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Re: QHY247c border shading only in Sharpcap

#9

Post by admin »

Hi,

changing to 4.0 will probably help with the borders as there were lots of changes added to try to support newer QHY cameras in SharpCap 4.0.

The removal of amp glow reduction was deliberate - SharpCap 3.2 showed that option for cameras that did not actually have the functionality, so actually the fact that the control appears in SharpCap 3.2 was a bug!

hope this helps,

Robin
Alessandro
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Re: QHY247c border shading only in Sharpcap

#10

Post by Alessandro »

Hello.

Many thanks for your reply and clarifications.
Now I will feel more confident to take pictures with this camera.
Yes I saw by the net that many users complained about that function that was there but didn't work.
In my case (probably I belong to the minority) the early "amp noise reduction" worked with the QHY183C:
without setting it to ON the amp glow and the bands were strongly marked..

By the way I have to say that I have just tried the new version 4.0
and already noticed simply by the dark frames that the picture is even more clear
than before. The noise has reduced comparing to the 3.2 version with "amp noise reduction" set to ON.

Alessandro
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