Mark Sawyer
23-Mar-2009, 17:35
A friend and former student has a small old aplanat/rapid rectilinear (two cemented doublets) that's been in the family for several generations, and would like to use it as a soft focus lens on a 4x5. It's rather sharp, and she doesn't want to use a diffusing filter. We're looking for a way to induce actual spherical aberration into the design.
Ernest PurDum's excellent article on soft focus lenses on the lf homepage has the following passage:
"There are ways of upsetting carefully calculated spherical aberration reduction besides changing element spacing. A thick glass plate is one. Adding various combinations of weak positive and negative elements, Proxar and Distar and the like, might be another."
Any thoughts on placing a quarter- or half-inch piece of glass inside the lense barrel to create aberrations? Other thoughts on how we might get the desired look out of it without causing permanent damage?
Ernest PurDum's excellent article on soft focus lenses on the lf homepage has the following passage:
"There are ways of upsetting carefully calculated spherical aberration reduction besides changing element spacing. A thick glass plate is one. Adding various combinations of weak positive and negative elements, Proxar and Distar and the like, might be another."
Any thoughts on placing a quarter- or half-inch piece of glass inside the lense barrel to create aberrations? Other thoughts on how we might get the desired look out of it without causing permanent damage?