|
|
 | | Author | |
|
| | Date | |
|
|
|
|
Phil Davis |
11:06 14 Dec 05 |
|
|
Jerry Cunningham |
19:50 16 Dec 05 |
|
|
Steve Nicholls |
1:19 18 Dec 05 |
|
|
Shannon Stoney |
6:16 1 Dec 05 |
|
|
Phil Davis |
11:24 1 Dec 05 |
  |
Shannon --
Measure the bellows length from the optical center of the lens to the film plane. This can be confusing because, in some types of lenses, the "physical center" of lens structure is not necessarily the "optical center." If you're unsure of your lens's structure, work with either the "distance" or "magnification" methods.
To use the magnification feature measure the length of some subject detail (A) and the length of the corresponding detail (B) in the ground-glass image. The magnification (M) is M=B/A and the exposure factor is (M+1)^2.
For example, if A=4 and B=2 then M=0.5 (the image is half as large as the subject) and the exposure factor is (0.5+1)^2 or 1.5^2 or 2.25x.
All of this stuff is in the book.
|
|
|
|
|
|
|
|
|
frank miller |
15:21 13 Nov 05 |
|
|
beth peaker |
2:19 5 Nov 05 |
|
|
Michael J. Taylor |
7:51 6 Oct 05 |
|
|
Jorge Gasteazoro |
15:27 10 Oct 05 |
|
|
Bob Sandstrom |
19:10 28 Aug 05 |
|
