Color corrector (secondary) and CA at DVinfo.net

Sassi Haham · August 6th, 2008, 09:11 AM

Hi all,
How do you correct for chromatic aberration within Vegas ?
I would like to know how experienced vegas users handle CA, a more aesthetic technique then mine ...
On the Rosi Starling Video grab I used the Color corrector (secondary).
I don't really know how to use this plug-in but I found that choosing the fringing color (cyan/blue) with the "select effect range" eyedropper tool and then sliding down saturation
I got rid of the CA (most of it).

Sassi

Andrew Kufahl · August 6th, 2008, 04:25 PM

Personally I believe you are using the correct tool. As far as what technique/settings to use depends on what you are dealing with. Reducing saturation on the affected area will get you more toward grayscale though, which leads me to this...

I looked at your sample photo, and the only place I could see obvious CA was on one of the leaves along the left edge. To me, it looks blue-ish green. I would think you'd want it to be green (to match the leaf), so I selected the effect range (like you) but then used "Rotate hue" until it changed to a green color that was closer to the leaf.

There are probably a ton of different ways to go depending on the extent of CA.

Andrew

Sassi Haham · August 17th, 2008, 07:27 AM

Andrew,
Thanks for your advice.
I wish though that there would be more control when picking the colour of the fringing area
Or some practical way to play with it or fine tune until getting rid of it.
Sassi

Bill Ravens · August 17th, 2008, 07:52 AM

Actually, I don't think this is right. CA is the result of an optical imperfection that focuses the different wavelengths of light at different locations on the film plane. (because different wavelengths refract differently when passing thru glass)I.E. red/magenta is shifted relative to green/cyan. In order to correct the problem, at least theoretically, one needs to shift each color value by the correct number of pixels to get everything to "line up". To manually desaturate the color fringe, which is what you do with the vegas secondary CC tool, is only concealing the problem, not fixing the problem.

I would refer you to the CA correction plugin for virtualdub or Lightroom.

August 6th, 2008, 09:11 AM	#1
Sassi Haham Regular Crew Join Date: Mar 2006 Location: Yaad, Galilee Posts: 117	Color corrector (secondary) and CA Hi all, How do you correct for chromatic aberration within Vegas ? I would like to know how experienced vegas users handle CA, a more aesthetic technique then mine ... On the Rosi Starling Video grab I used the Color corrector (secondary). I don't really know how to use this plug-in but I found that choosing the fringing color (cyan/blue) with the "select effect range" eyedropper tool and then sliding down saturation I got rid of the CA (most of it). Sassi Attached Thumbnails

August 17th, 2008, 07:27 AM	#3
Sassi Haham Regular Crew Join Date: Mar 2006 Location: Yaad, Galilee Posts: 117	Not enough control Andrew, Thanks for your advice. I wish though that there would be more control when picking the colour of the fringing area Or some practical way to play with it or fine tune until getting rid of it. Sassi

August 6th, 2008, 04:25 PM	#2
Andrew Kufahl Regular Crew Join Date: Apr 2008 Location: Menasha, WI Posts: 88	Personally I believe you are using the correct tool. As far as what technique/settings to use depends on what you are dealing with. Reducing saturation on the affected area will get you more toward grayscale though, which leads me to this... I looked at your sample photo, and the only place I could see obvious CA was on one of the leaves along the left edge. To me, it looks blue-ish green. I would think you'd want it to be green (to match the leaf), so I selected the effect range (like you) but then used "Rotate hue" until it changed to a green color that was closer to the leaf. There are probably a ton of different ways to go depending on the extent of CA. Andrew

August 17th, 2008, 07:52 AM	#4
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	Actually, I don't think this is right. CA is the result of an optical imperfection that focuses the different wavelengths of light at different locations on the film plane. (because different wavelengths refract differently when passing thru glass)I.E. red/magenta is shifted relative to green/cyan. In order to correct the problem, at least theoretically, one needs to shift each color value by the correct number of pixels to get everything to "line up". To manually desaturate the color fringe, which is what you do with the vegas secondary CC tool, is only concealing the problem, not fixing the problem. I would refer you to the CA correction plugin for virtualdub or Lightroom.