Number of elements in a lensgreenspun.com : LUSENET : Large format photography : One Thread
I have been using older used lenses, until now. I am ready to buy a new lens but am slightly confused by the selection.
Some lenses are 3-4 elements others are 5-6. Optically is there a difference? I would understand wieght as an issue, but for studio use the optical precision is a higher factor.
-- Michael Forney (firstname.lastname@example.org), May 20, 1998
According to a not-to-recent Calumet catalog I have the greater the number of elements a lens the better corrected it is for distortions.
-- Mark Windom (email@example.com), May 20, 1998.
Usually, the angle of coverage dictates the number of elements needed. A long focal length lens has a smaller angle of coverage than a short focal length lens for a given film size. Since longer lenses need a smaller angle of coverage, you dont need many elements to give the needed corrections, where a short lens, with a wide angle, needs more corrections. Many older lenses are tessar types (4 element), with about 55 degrees of good definition. If this covers your film, then it should perform just fine. All things being equal, the fewer elements the better, from a flare point of view.
-- Ron Shaw (firstname.lastname@example.org), May 21, 1998.
Mike, since each optical surface is used by the designer to correct an aberration, it would be safe to buy lenses with more elements. I disagree with the other post that said the angle of view determines the number of elements. The Plasmat design (air spaced Dagor with six elements)has been used for 80mm lenses as well as long focal lengths. SR
-- Steve Rasmussen (email@example.com), July 01, 1998.