OSC - ZWO ASI 533MC Pro - White Balance

Somewhere to ask questions about the best way to use SharpCap
Post Reply
NeilG
Posts: 78
Joined: Wed Feb 22, 2017 9:36 pm

OSC - ZWO ASI 533MC Pro - White Balance

Post by NeilG » Mon Feb 10, 2020 3:23 pm

Any recommendations on which is best:-
White Bal (Red) 50 and White Bal (Blue) 50 or
white bal (red) auto and white bal (blue) auto

Or just what difference does it make?
Regards
Neil
Scopes: Celestron C11, 102SLT , Ascension 127mm Apo, Opticstar 152mm Mak, Ascension 80mm Apo
Mounts: EQ8, EQ5 Pro, Nexstar SLT
Imaging: ASI1600MM-Cool, ASI533MC-Pro, ASI290MM, ASI224MC, Quark, QHY5L-II-M,
Opticstar 82 eyepieces, lots of other stuff

mAnKiNd
Posts: 307
Joined: Sun Jun 11, 2017 4:55 pm
Location: Long Island, NY
Contact:

Re: OSC - ZWO ASI 533MC Pro - White Balance

Post by mAnKiNd » Mon Feb 10, 2020 9:03 pm

I'm under the impression that if you mess with those sliders, you are differentially changing the gain structure for the pixels underneath those (i.e red or blue) color filter arrays.

Doing this, afaik, would change the full well depth, read noise, dynamic range etc.. in those pixels, so while you might be capturing what seems like a unison RGB histogram, the underlying data that is saved in your FITS file is not uniform in its "electronic characteristcs" for the each pixel group within the RGGB matrix. I'm not 100% about this, and it seems every manufacturer approaches this differently, so take my comments with a grain of salt until someone with actual knowledge of this clarifies

Having said that, some people don't mind achieving color balance in the acquisition phase this way, others do. Personally I leave them at default 50 and always try to make those adjustments in post- Recently, I'm exploring how light pollution filters might achieve a better native OSC white balance without touching those R and B gain sliders.

Finally to specifcally address your question :lol: the few times i've tried messing around with those sliders, I felt more comfortable doing it manually, until I match the RGB peaks by eye and visually confirm by looking at the image. I never full trust "auto" on anything, i.e. which is why I prefer the semi-automated focusing in sharpcap!

In any case, whatever you choose to do, as always just make sure you keep the same settings when acquiring darks, bias and flats :)

Hope this helps?
Minos

NeilG
Posts: 78
Joined: Wed Feb 22, 2017 9:36 pm

Re: OSC - ZWO ASI 533MC Pro - White Balance

Post by NeilG » Mon Feb 10, 2020 9:16 pm

Thanks for that - similar to my thinking.

Seems sensible to set WB to 50/50/50 and balance later in post processing - almost the same as doing RGB with a mono camera .
Neil
Scopes: Celestron C11, 102SLT , Ascension 127mm Apo, Opticstar 152mm Mak, Ascension 80mm Apo
Mounts: EQ8, EQ5 Pro, Nexstar SLT
Imaging: ASI1600MM-Cool, ASI533MC-Pro, ASI290MM, ASI224MC, Quark, QHY5L-II-M,
Opticstar 82 eyepieces, lots of other stuff

User avatar
admin
Site Admin
Posts: 4976
Joined: Sat Feb 11, 2017 3:52 pm
Location: Vale of the White Horse, UK
Contact:

Re: OSC - ZWO ASI 533MC Pro - White Balance

Post by admin » Mon Feb 10, 2020 10:00 pm

Hi,

Yes, as Minos says adjusting those controls may be applying different gain values to the colour channels which could lead to different read noise characteristics, dynamic ranges and so on. Actually that's the best case scenario – in the worst case scenario adjusting those sliders is making adjustments to the data digitally somewhere in the camera SDK before the image gets to SharpCap. If you drag the slider is down it may be multiplying each value by some constant this is less than one – perhaps 0.5 as an example – this could stop the colour channel being adjusted from fully saturating and can end up throwing away useful detail in the image data.

Cheers, Robin

mAnKiNd
Posts: 307
Joined: Sun Jun 11, 2017 4:55 pm
Location: Long Island, NY
Contact:

Re: OSC - ZWO ASI 533MC Pro - White Balance

Post by mAnKiNd » Mon Feb 10, 2020 11:09 pm

There's plenty of other useful buttons and sliders in Sharpcap one can play with :lol:

I can safely assume that leaving these sliders at default is for the best, at least for the deep sky imaging I'm trying to enjoy.

umasscrew39
Posts: 349
Joined: Fri Apr 28, 2017 1:28 pm
Location: Central Florida
Contact:

Re: OSC - ZWO ASI 533MC Pro - White Balance

Post by umasscrew39 » Tue Feb 11, 2020 12:03 am

I have been using the ZWO ASI553MC Pro since it first became available and have gotten some very nice images. I always leave them set at 50/50 and just post-process. The colors are excellent.

mAnKiNd
Posts: 307
Joined: Sun Jun 11, 2017 4:55 pm
Location: Long Island, NY
Contact:

Re: OSC - ZWO ASI 533MC Pro - White Balance

Post by mAnKiNd » Tue Feb 11, 2020 1:01 pm

Indeed you have very nice images! Keep it up :)

User avatar
Menno555
Posts: 240
Joined: Mon Apr 20, 2020 2:19 pm
Location: The Netherlands
Contact:

Re: OSC - ZWO ASI 533MC Pro - White Balance

Post by Menno555 » Fri May 22, 2020 8:59 am

admin wrote:
Mon Feb 10, 2020 10:00 pm
Hi,

Yes, as Minos says adjusting those controls may be applying different gain values to the colour channels which could lead to different read noise characteristics, dynamic ranges and so on. Actually that's the best case scenario – in the worst case scenario adjusting those sliders is making adjustments to the data digitally somewhere in the camera SDK before the image gets to SharpCap. If you drag the slider is down it may be multiplying each value by some constant this is less than one – perhaps 0.5 as an example – this could stop the colour channel being adjusted from fully saturating and can end up throwing away useful detail in the image data.

Cheers, Robin
Bit confused now. I was under the impression that manually using the white balance sliders was best? So lining up the Red and Blue with the green and white to get a uniform, even histogram? I mean, when I do that, the histogram in PS with processing is almost equal then too.
But if I understand correctly, that way data can be corrupted or image details can be lost or exaggerated?

Post Reply