reversing a 240mm lens for close-up photographsgreenspun.com : LUSENET : Large format photography : One Thread
i have previously asked regarding a closeup lens for 8x10 format. i received several responses, one of which included the suggestion of reversing a 240mm lens. i have never heard of this. is this okay and a good suggestion?
-- howard b. schwartz (email@example.com), December 10, 2001
Depends. If you're doing work wel above life size, a reversed enlarging lens can indeed give you superb results. Think about. An enlarging lens takes a negative of a given size and projects it to a larger size. In this range, it is working in the area it was optimized for. If you use it to take a picture of a small area, in effect it is taking a small area and enlarging it onto film instead of paper. Again, it is working in the range it is optimized for.
In general, lensees are designed to be optimum at certain conjugates. Most lenses have the longer distance in front of them and the shorter distance behind them. So it is logical that turning a lens around when you work beyond 1:1 is a good idea. Cheers, DJ.
-- N Dhananjay (firstname.lastname@example.org), December 10, 2001.