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Discussion Starter #1
Doing some research on chromatic aberrations of camera lenses & figured some smart people on this board may have looked into it before. Anyone know of any good resources for researching chromatic aberrations? Without getting too deep into it, I'm writing some software to correct for it as a post process. Anything relevant would be much appreciated. ;)
 

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cerven said:
I looked up abberations on the WWW and you don't want to know what I got back! LOL :D
i know this is old and you probably already know this, but try ' miserable failure ' in google. there are several other google bombs like this. :D not it's not an abberation either
 

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I know what CA is. I know which of my lenses have it, and which have it bad. :) But, I really have nothing useful to add.

I also know that the new PhotoShop CS RAW image processor has a very nice CA-reduction algorithm in it for both color shifts. You might see what you can find published on how it works. For the most part, it's able to nuke my purple fringe without damaging the rest of the picture at all. :bow:

I dread taking wide-angle pictures with tree branches and bright sky in the corners -- no better way to tease CA out of an otherwise fine piece of glass.

I read a whitepaper on some of the tricks Canon uses to try to reduce CA in their lenses, and it's seriously voodoo stuff, like StarTrek science with nanocoatings, gas-deposited chromatic interference layers, rare elements.. software is definitely the way to go. :)
 

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Discussion Starter #5
[nerd]
... and I present you with the chromatic abberation correction of my Canon Powershot G5 shooting through it's wide angle attachment displayed as UV offsets mapped to red & green and amplified 1000 times.
[/nerd]

::sigh:: where's my car?
 

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Have you checked out the DXO approach? They carefully measure body/lens or all-in-one camera performance and then using the EXIF data and the known flaws try to correct it. I use it with my D70 when shooting JPEGs. www.dxo.com They are only correcting for lateral CA at the moment, as far as CA goes, along with some other optical problems noted below. I like the idea of correcting for things they know the camera is doing wrong. The software works on batches, is fast and takes into account which lens, focal length, focus distance, etc. Much more to it than that. They measure cameras over MANY individual positions at all apertures and focal lengths and then correct for blur, vignetting, CA, and geometric distortion at each of those points. At some point stuff like this will be built into the cameras I suspect. Read their FAQ - it's pretty good. My shots show the same kind of improvement as seen on their site. Raw version and noise reduction this Fall.

Stan
 

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Discussion Starter #8 (Edited)
Stan said:
Have you checked out the DXO approach?
I hadn't. Didn't know they existed. Their software seems to be great at correcting parallax... wish they had better CA correction demos.

Regardless, it doesn't appear they have corrections for the f-theta (180 degree fisheye) lense I will eventually be correcting.

Interesting none the less... I might look into this more for my own personal use. Thanks for the suggestion!
 
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