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Layer masks to correct CV15 cyan drift?


tashley

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Ages ago, on the M8, many of us got around the cyan drift issues on the CV15 by shooting a blank white wall, inverting the result in photoshop and then pasting it into a new layer above any image we had that showed the colour issues, with the layer mode set to 'color dodge'.

 

I have tried the same thing this afternoon and can't get it quite right: the layer I am using which shows the inverted radial shift is much lighter than the ones I used back with the M8 and though darkening it using 'brightness' gives better results, it's still not as good a correction as I used to get. And of course I can't use the layer I had from back then, because it was shot on a cropped sensor...

 

Can anyone remember step by step the exact technique?

 

I know I could use corner fix but I'd really like to be able to do it this way.

 

I already tried to use the Lens Cast Calibration feature in C1 as I do with my Phase One files and wide angle lenses, but it only works for Phase files... and I can't find a way of tricking it. Grrr....

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I think that you will have to get into the LAB masking techniques advocated by Dan Marguiles. The Canyon Conudrum book gives a number of techniques that could be the answer. Please don't ask me to explain in a forum post ;) just reading them gives me a headache, but they do work.

But to keep it simple, did you try Cornerfix?

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I think that you will have to get into the LAB masking techniques advocated by Dan Marguiles. The Canyon Conudrum book gives a number of techniques that could be the answer. Please don't ask me to explain in a forum post ;) just reading them gives me a headache, but they do work.

But to keep it simple, did you try Cornerfix?

 

Thanks Buddy - but there really was a much easier way, we were all using it at the time. It was just one calibration shot, inverse it, make an adjustment layer and change the blending. I am missing one vital step, have lost the Photoshop Action that used to do it for me and can't find the threads in which I and others explained how to do it!

 

:-(((

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Thanks Buddy - but there really was a much easier way, we were all using it at the time. It was just one calibration shot, inverse it, make an adjustment layer and change the blending. I am missing one vital step, have lost the Photoshop Action that used to do it for me and can't find the threads in which I and others explained how to do it!

 

:-(((

 

Well, I would appreciate that a lot. As it is, my CV 15 is gathering dust because I can't be bothered :o

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This post:

 

Love those Chicago images.

 

Why can you not correct cyan corners using a redial gradient in photoshop. It needs to be set as a clear or white to red. Start in the center and draw the gradient into a corner.

 

Adjust the mid point of the grad so as the red starts at the same place as the cyan and they should cancel perfectly. You can even make an action to do it on a blank layer.

 

From this thread:

 

http://www.l-camera-forum.com/leica-forum/leica-m8-forum/80321-my-voigtlander-15-heliar-report-up-3.html

 

Bob

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This post:

 

Love those Chicago images.

 

Why can you not correct cyan corners using a redial gradient in photoshop. It needs to be set as a clear or white to red. Start in the center and draw the gradient into a corner.

 

Adjust the mid point of the grad so as the red starts at the same place as the cyan and they should cancel perfectly. You can even make an action to do it on a blank layer.

 

From this thread:

 

http://www.l-camera-forum.com/leica-forum/leica-m8-forum/80321-my-voigtlander-15-heliar-report-up-3.html

 

Bob

 

 

Thanks! What I am trying to achieve is more specific to each camera/lens combo and can be aperture specific too, since the inverted 'white wall' shot used in place of the gradient is an exact 'fit' to the specifics of the situation.

 

I used to use it a lot and it was 100% effective but I just can't remember it!

 

Time for Cornerfix I think!

 

Best

 

Tim

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