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Mozilla's Close Focusing Nightmare:
Despite his small size, and evil demeanor, Mozilla is a beautiful iguana. I had wanted to get "more personal" close-up portraits of Moz, but only had a consumer macro lens, a kit of chromatic close-focusing filters and a 2X tele-converter to work with. None of these components were designed to work together. After snapping three close-focusing filters to my fully zoomed macro lens and attaching the 2X tele-converter to the other end, I had not only created the strangest looking lens known to man, but unbeknownst to me, I had also created the most chromatically-aberrant lens known to man.
Upon developing the pictures, I noticed what looked like some pretty bad color bleed, as illustrated on the blow-up of the original scan. What had happened was that by stacking numerous chromatic lens elements, and because blue refracts more than red, I had created a picture where the blue and red no longer converged. The blue layer was actually at a substantially higher magnification than the red layer, and the green layer was right in between. I really liked Mozilla's portrait, so this had to be corrected.
To correct this, I used Corel Photo-Paint to separate the R-G-B layers, and zoomed out a small percentage on the blue layer and then zoomed in a small percentage on the red layer and then recombined the layers into a single image. Voila, no more chromatic aberration, and a nice sharp picture from a very hokey lens setup! This process admittedly took a lot longer than was easy to justify, but c'est la vie.
2002 Update: There is now a Photoshop patch called "Panorama Tools" which does every form of image distortion manipulation and correction imaginable. It also has the ability to correct this type of distortion with very little effort, which is ironic since my newer better lenses no longer require this...
-Michael