Previous versions of jjlphoto's message #6738311 « 2 new lenses, 17 and 24mm TSE »
jjlphoto Offline [X]
Re: 2 new lenses, 17 and 24mm TSE
Jim Roof wrote:
.....since most 35mm WA lenses were not designed to the same exacting standards as LF lenses. BTW, MF lenses barrel distort too....
Jim- actually the opposite is the case. Since 4x5 get enlarged very little compared to a 35mm size, 4x5 lenses didn\'t need to be that good at all. The barrel distortion is because lenses for reflex cameras (cameras with mirrors and pentaprisms) are of the \"retro-focus\" design school. That means they are planted further away from the film plane than a rangefinder or large format lens is designed to sit (in order to clear the mirror.)
The Hasselblad 38mm Biogon was a symmetrical lens design, and hence was sold permanently mounted on a very thin Hasselblad body that did not have a mirror (or focus screen on top). It had very little noticeable linear distortion (barreling) as a result. Compare that to its closest cousin that gets used on a conventional 500 series Hasselblad body, the Hasselblad 40mm Distagon, and that lens shows lots of barreling. Same thing when you compare the Zeiss 21mm Biogon for the M-mount rangefider (very little linear distortion) against the Zeiss 21mm Distagon for the SLR (more barreling again).
cineski wrote:
JJL- When I mean 16mm on 35 vs 47 on 4x5, to me, a 16mm simply distorts a lot. Whereas a 47mm focal length should distort much less. When you put the two lenses on their designed for system to get the same field of view (due to crop factor) the distortion of the 16mm would be much worse. Am I wrong or right no this?
The 16mm on a 35mm system would show barreling (more linear distortion) because of the deficiencies of retrofocus design principles, not because it is for a smaller format. If you used a Zeiss 15mm M-mount rangefinder lens and compared it to the same 16mm Canon SLR lens, the SLR lens would show notable barreling, the rangefinder lens would show much less. And both are on a FF 35mm frame.
Feb 18, 2009 at 06:15 PM
Previous versions of jjlphoto's message #6738311 « 2 new lenses, 17 and 24mm TSE »
