Posted by Les on February 03, 2001 at 12:07:11:
In Reply to: Re: 65 mm lens on a Century! posted by Mal Stone on February 03, 2001 at 09:37:02:
The focus scale that's on the camera is for the 101 and cannot come close to being used for the 65mm lens. Here's the reason behind it.
There's a rule of optics/physics that says if you put any lens twice it's focal lenght from the film plane it will focus at twice it's focal length away and the object will be 1:1.
So with the 65mm lens 130mm away from the Ground Glass it will focus a 130mm away from the lens (roughly 5") It will also focus at infinity by moving the lens 65mm away from the groung glass.
Thus, a 65mm movement onthe rails will cover everything from 5" to infinity.
The 101mm lens will focus at 1:1 at 202mm or close to 8" from the ground glass and go to infinity with not a 65mm shift but a 101mm shift.
the two scales are radically different