I'm no expert on optics, but I would guess that, like Vicente says here, the more refraction an element causes, the more chromatic distortion would be created by that lens and using UD glass in that element would reduce the overall chromatic distortion of the lens to a great degreee. Whether or not the most bending occurs in the larger or smaller elements is probably a matter of lens design, but the one with the greatest refraction should get the UD. If a lens is too cheap to put the UD in a large, high refractive element, then the original idea holds.
>From all I know, UD glass does not reverse the order of the cromatic abberation (unlike Canon's DO technology), so all elements contribute to it...so, shouldn't every element be UD glass for the most corrected lens? Or do positive and negative lens elements cause chromatic distortion in opposite ways (like the DO technology) which can offset some of the abberation without using UD glass? Mike Vicente wrote: > > > As the lenses are used to "bend" the light rays. I think that the driving > example was quite adequate. > If you bend more the light, you get more aberrations. > I suppose that big lenses bend the light more than small ones. > > Best regards > > Vicente -- Michael Shupe Michigan Tech University www.northernlightsgallery.com * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
