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easiest way to introduce chromatic abberation?
i have to introduce chromatic abberation into some effects to match the amount of ca in the live action plates. director’s orders.
what’s the easiest way to do this? i could split the comp into three more comps, one for the r g and b channels, then shift/scale them, then recombine the 3 comps, but apparently chromatic abberation is more pronounced at the edges of a shot and also varies according to an object’s distance from the lens – so really i need to be able to mask the effect with soft masks or something like that.
was just wondering if there was a plugin that would do it… i have sapphire and tinderbox but nothing’s jumping out at me. s_blurchannels isn’t it.
any plugins with adjustable parameters, or do i have to do it the manual way on all my comps?
thanks,
scott. -
6 Replies
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Boris has a Channel Offset – this splits the image into RGB channels.
Not sure if its what you need. Might help.
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Hi Scott; I’d try Sapphire S_WarpChroma. It’ll give you more CA near the frame edges, and you can mask it as needed by putting a grayscale mask into the Matte input.
Set the From Z Dist to a little over 1, and To Z Dist to 1 for a good start.
— Gary
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Off the top of my head without using external plugs, Duplicate your layer till you have 3 copies. Use the channel effects to isolate just the R, G, and B on each layer respectively. Then on each layer add the “Optics compensation” plug and set each layer to slightly different settings. Then use the screen overlay on the top 2 layers.
Don’t know if it works, but thinking out loud.
Chris Smith
https://www.sugarfilmproduction.com -
I just sat down and tried my thoughts and I gotta say it looks pretty close. Use “Set Channels” effect on each layer and leave one channel on and turn the other 2 off. So in the end each duplicate is Red or Green or Blue. Screen the first 2 layers over the layer below it. Add optics compensation to the top 2 layers. Set it to ‘reverse’ then a value of about 20 on one layer and 30ish on another layer. Then the middlw of the image stays true while as it goes towards the edges, the channels shift away from each other.
Chris Smith
https://www.sugarfilmproduction.com -
Hi Chris,
Thanks for the detailed response. This was basically what I was planning to do originally, but I wasn’t sure how subjective this method would be – I can tell there’s going to be a lot of back and forth with the director and VFX sup saying “no too much, oh, now there’s not enough”. I thought perhaps there was a plugin that would replicate settings for different lens types and film stock (or CCD’s?). Guess not… something for Digital Film Tools to work on, perhaps?
Guess I’ll do it the manual way! 🙂
Thanks again,
Scott.Oh, and thanks Gary also, I’m going to try your idea as well and compare.
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The Panopticum lens plug-in has chromatic abberation as a parameter built in called “Color deviation of the glass”.
Chris Smith
https://www.sugarfilmproduction.com
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