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View Full Version : Retrofocus Wide-Angle for LF - is this possible?



Carlos Co
4-Apr-1999, 18:09
Has any manufacturer ever attempted to build/sell a retrofocus (or inverted tele photo) lens for LF cameras. Looking at the block diagram for the Canon 24 mm TS lens which is well known for its excellent image quality:

http://www.canon.co.jp/camera-museum/lens/index.html

do you think something similar can be made for LF cameras? I would imagine that retrofocusing a lens would reduce light fall-off as well or am I completely wro ng about all of this?

Ellis Vener
4-Apr-1999, 19:03
Besides there not being a perceived need for retrofocus designs in LF, I wonder if an inherent problem with a retrofocus design might be a smaller image circle?

Lanier Benkard
19-Apr-1999, 13:41
I read a post by Richard Knoppow on rec.photo.large-format that said that he did not know of a retrofocus lens for LF. If he said it you can be pretty sure its true. I imagine one difficulty is that retrofocus designs are inherently asymmetric, which means they stink at close range, hence the floating elements usually used in 35mm lenses to correct for this. Since performance at close range is important for wide-angles and there is no real need for retrofocus in LF, I guess noone has ever bothered.

holmbāgu
6-Mar-2012, 12:59
I read a post by Richard Knoppow on rec.photo.large-format that said that he did not know of a retrofocus lens for LF. If he said it you can be pretty sure its true. I imagine one difficulty is that retrofocus designs are inherently asymmetric, which means they stink at close range, hence the floating elements usually used in 35mm lenses to correct for this. Since performance at close range is important for wide-angles and there is no real need for retrofocus in LF, I guess noone has ever bothered.

Reviving a very old thread. There has been been one need for a retrofocus LF lens; one-shot/tri-colour cameras. The 133mm f/5.3 Curtis Color Stellar is one such example on a 4x5" three-color camera. http://www.vintagephoto.tv/scouts2.shtml

Leonard Evens
7-Mar-2012, 13:05
It might be noted that many wide angle large format lenses have a mildly inverted telephoto or retrofocus design. That is true for both my Rodenstock Grandagon N 90 mm f/6.8 and 75 mm f/4.5 lenses. You can tell that from the fact that the flange focal length exceeds the focal length.