View Full Version : Purple fringing


Jeff Price
October 18th, 2003, 11:50 AM
What, exactly, causes purple fringing? Is it a finction of the CCD or the lens or perhaps a filter? Is going to APO the only way to completely avoid it on a lens?

Once you have an image with purple fringing has anyone developed a photoshop plug in to deal with it? Manual manipulation takes a tremendous amount of time and is only effective if the amount of fringing is small.

Thanks.

Jeff Donald
October 18th, 2003, 01:08 PM
There can be several causes of purple fringing. The most common is CA (Chromatic Aberation (http://www.dvinfo.net/articles/optics/lensdefects.php)). Several of the PS plugins that allow for adjustment of barrel distortion also adjust CA. Better lenses will also exhibit less CA. Canon's L series telephotos and Nikon's ED lenses show little or no CA. Wide angle lenses, by virtue of their design rarely show CA.

Other causes can be CCD, low light, low S/N ratio, high ISO etc. The software is pretty good at eliminating the visual effects of CA.

Jeff Price
October 18th, 2003, 03:28 PM
Do the photoshop plugins work with elements or just the full blown photoshop?

Jeff Donald
October 18th, 2003, 03:30 PM
Good question, I don't use Elements. If I have time I'll load my copy of Elements and try a plugin or two. Anyone know for sure?

Jeff Price
October 28th, 2003, 04:16 PM
Jeff, Do you have a name or web address for some of these plug-ins? I can just try it and see if it works in elements (many of them do).

Thanks.

Jeff Donald
October 28th, 2003, 05:44 PM
Try searching Image Factory And Fred Miranda. Both make many plugins for PS. I just don't know if they work in Elements. I didn't think Elements could use plugins.