Re: Dealing with vignetting
Posted: Sat Feb 02, 2019 7:04 pm
I'm making a couple of assumptions here (we all know what that can lead too.) You have not provided your exposure and gain settings but i'm assuming you're using a relatively short exposure being that you are using Hyperstar. I notice your brightness setting is at 5, for short exposure this is too low. Try turning this up by 5 and seeing if the histogram shape in live stack is off the left edge. Keep adjusting until you get the histogram shape you want but don't over do it with brightness. If you go too far with brightness you'll start getting some ugly vignetting with the 294.
Don and I both broadcast on NSN and we have come up with different process to get the results we're after. We've been testing various different methods for creating flats for the 294. This camera is very color sensitive and you'll find it can be frustrating to get this right for live stacking but it can be done.
My process for flats:
Exposure: 200 - 375 ms (this depends on use of filters, reducers and anything in the image train, will also vary with your flat panel or other light source)
Gain: 300
Brightness: 0
WB Red: 50
WB Blue: 50
--- Flats tools settings---
- enable subtract bias frame
- create monochrome flat
- for exposure and gain - for my RC6 I've provided the gain and exp settings that work for me. in setting the exp and gain adjust until the histogram is almost clipping the left side. I usually stay about 95% with the left most edge of the highest color curve, in my case green channel. I average 50 frames and that's the master flat for the night.
Once you start live stacking and you have two frames stacked the histogram will become live and you'll notice the color are way out of alignment. Don't be alarmed! apply an auto stretch and auto white balance in live stacking. You may notice red channel gets a severe boost just give this a slight nudge and it we bring it down. Now watching the Display histogram adjust your red, green and blue channels to get alignment. From hear on I try to make all stretching adjustments to the Display histogram leaving the Live stack histogram alone except for minor tweaks and adjustments to taste.
Hope this helps
-Wikkett
Don and I both broadcast on NSN and we have come up with different process to get the results we're after. We've been testing various different methods for creating flats for the 294. This camera is very color sensitive and you'll find it can be frustrating to get this right for live stacking but it can be done.
My process for flats:
Exposure: 200 - 375 ms (this depends on use of filters, reducers and anything in the image train, will also vary with your flat panel or other light source)
Gain: 300
Brightness: 0
WB Red: 50
WB Blue: 50
--- Flats tools settings---
- enable subtract bias frame
- create monochrome flat
- for exposure and gain - for my RC6 I've provided the gain and exp settings that work for me. in setting the exp and gain adjust until the histogram is almost clipping the left side. I usually stay about 95% with the left most edge of the highest color curve, in my case green channel. I average 50 frames and that's the master flat for the night.
Once you start live stacking and you have two frames stacked the histogram will become live and you'll notice the color are way out of alignment. Don't be alarmed! apply an auto stretch and auto white balance in live stacking. You may notice red channel gets a severe boost just give this a slight nudge and it we bring it down. Now watching the Display histogram adjust your red, green and blue channels to get alignment. From hear on I try to make all stretching adjustments to the Display histogram leaving the Live stack histogram alone except for minor tweaks and adjustments to taste.
Hope this helps
-Wikkett