Bellows/Lensgreenspun.com : LUSENET : Large format photography : One Thread
Pardon any dumb questions I may ask since I'm completely new to L F. I'm trying to understand the relationship, if any, to bellows extentions and lens focal length. I read about bellows extentions alot here, in my few days of visiting this site. I also am thinking seriously about moving up to LF, but really don't know where to begin. I've noticed 2 or 3 Brand/models of starter cameras keep showing up, which probably means they're all pretty good. Does any of these accept 120 roll film backs.
-- Jarrell Conley (firstname.lastname@example.org), September 17, 1998
I think most any LF camera can take a roll film back, however, I think if you want to use roll film, make it easy on yourself and use a MF camera. If Im going to the trouble of LF, I want that LF negative! LF cameras use a bellows to couple the lensboard to the back. You have seen these, and there is a limit on how much you can 'stretch' them. If you mount a 150mm lens, for instance, you must rack out the bellows approx. 150mm when focused at infinity. If you mount a 300mm lens, you must rack it out a corresponding amount. At some point you reach the limit of your bellows. Keep in mind that as you focus closer than infinity (as is usually the case), you must also rack out the bellows. The camera you choose must have a bellows that will handle the lens you need. Most field cameras have 'double extension bellows', which means it will rack out twice the distance required to focus a 'normal' lens to infinity. (for instance, a normal lens for 4x5 is 150mm, so a double extension bellows should rack out to 300mm, which will give you 1:1 with that 150mm lens.)
-- Ron Shaw (email@example.com), September 17, 1998.