Live Stack with Flat Frame Bug?

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Posts: 162
Joined: Sat Jun 23, 2018 8:48 pm

Re: Live Stack with Flat Frame Bug?

Post by BlackWikkett » Fri Mar 15, 2019 10:32 pm

I capture in fits format and select save exactly as seen in the drop down dialog of Live Stacking. This saves an 8 bit PNG file. Since I mainly share my images via Flickr the 8 bit format is fine for that. I capture in fits so in case I decide to capture individual frames for later processing I'll not forget to make the change to fits.

To white balance in Photoshop I use 50% gray layer with difference blending and a threshold layer to pick mid point for curves mid point. This video explains it way better than I can in a short text blurb.

I use an IDAS D1 light pollution filter which really steps on the red channel this is the primary reason I have to do additional white balance.

In Photoshop I usually also try noise reduction and some sharpening and saturation. I use multiple tools for this some built in and some free and paid filters and actions. For most of my images I usually spend no more than 5-10 minutes editing in Photoshop. I like the immediacy of SC Live Stacking and keeping the processing to a bare minimum.

Posts: 122
Joined: Sat Mar 25, 2017 1:57 am

Re: Live Stack with Flat Frame Bug?

Post by donboy » Tue May 07, 2019 8:57 pm

admin wrote:
Tue Mar 12, 2019 10:16 pm

My approach is to never touch the colour balance controls that come with the camera (leave them at their default settings or set them back to those if you have changed already). The problem is that for most cameras the colour balance is performed as a digital manipulation of the post ADC image data, meaning that it is somewhat destructive to image quality. I believe there are a few cameras where the colour balance controls actually are implemented through separate analogue gains for the R/G/B channels, which would be fine to use, but it is unclear which manufacturers or models work this way.

So, the goal is to do the minimum amount of manipulation of the image data prior to stacking.

With regards to flat frame and dark frame correction, all of the controls on the right-hand side with the exception of the post processing block can potentially affect the image that comes from the camera into SharpCap. Any of these that clearly make changes to the live image from the camera should be kept the same between dark frames and image frames and should only be changed cautiously between flat frames and image frames.

Cheers, Robin
That's all well and good if not using filters, but what if one uses LP filters which tend to disrupt the color balance. I've found for myself that adjusting the R & B sliders to achieve a color balance to work better. If I try and set the R & B to default (50/50) for my ASI294 then the Red slider in Live Stack doesn't have enough adjustment and when ACB for Live Stack is pressed it sends the Red slider to maximum, thus requiring the Green slider and the Blue slider to be reduced so Red channel can be balanced. And the whole ACB in Live Stack becomes a manual operation with slight loss in overall signal. Additionally, the calibration files for me work better when I use the same color balance settings as used when capturing Lights.


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