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Mailinglist:PanoTools NG
Sender:Hans
Date/Time:2009-Dec-18 15:50:22
Subject:Re: CA for sigma fisheye in dcraw

Thread:


PanoTools NG: Re: CA for sigma fisheye in dcraw Hans 2009-Dec-18 15:50:22

--- In #removed#, "prague" <360cities@...> wrote:
>
> Hans you're WRONG! 
> :-DDD
> 
> DCRaw has supported CA correction for a couple years now, apparently.

Yes but as I said only with simple scaling factors.
That is the only way unless they are hiding something for them self.

This DCRaw tutorial updated in june has not a word about it.
http://www.guillermoluijk.com/tutorial/dcraw/index_en.htm

A search for DCRaw and Color Aberration or chromatic aberration only gives pages that talk about the same as I said in my first post.
It was added in 2007.
2007-06-02 dcoffin * dcraw.c: Added "-C" option to correct chromatic aberration.

The factor is exactly the same as you can do yourself in Photoshop with a simple batch action.

Hans

> 
> PS and other raw programs' CA settings don't translate from one to another. hence my question. (and yes I know, each lens might differ a bit)
> 
> thanks,
> Jeffrey
> 
> --- In #removed#, "Hans" <hans@> wrote:
> >
> > 
> > 
> > --- In #removed#, "Jeffrey Martin | 360Cities.net" <360cities@> wrote:
> > >
> > > has anyone corrected the CA for their sigma 8mm 3.5 or 4 in dcraw?
> > > 
> > > i'd really like to know what settings you used.......
> > 
> > As far as I can see the only way to reduce CA in DCRaw is to use the same way as I did in Photoshop way back in 2002 before Ca reduction in Camera Raw existed. Not really a way to do it today but if you really want you can just find the factors in Photoshop first using your eye.
> > Cited:
> > Enlarge the raw red and blue layers by the given factors, typically 0.999 to 1.001, to correct chromatic aberration.
> > 
> > Hans
> > 
> > 
> > > 
> > > 
> > > 
> > > Jeffrey Martin
> > > tel. +420 608 076 502 / skype jeffrey.s.martin
> > > www.360cities.net - The world's best panoramic photography
> > > www.panoverflow.com - How to make Panoramas
> > > facebook.com/360cities - Join us on Facebook
> > > twitter.com/360cities - Follow us on Twitter
> > > 
> > > 
> > > [Non-text portions of this message have been removed]
> > >
> >
>




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