Improvising: long focal length lensgreenspun.com : LUSENET : Large format photography : One Thread
I hope to do a portrait on 4x5 early next week and the longest lens I have is 180mm. I would ideally like to use a 300mm but I can't afford to buy one and would prefer not to have to hire one unless I have to.
I discovered after a little experimenting that removing the front cell of my 180 Symmar-S (i.e. using only the rear cell) extends the focal length of the lens considerably (perhaps to around 300 though I have not measured it).
Does anyone have any thoughts on the viability of this 'improvisation'?
-- Simon Rodan (email@example.com), August 08, 2001
I have an older Symmar f1:5.6 210 mmand if I take only the back element then I get f1:12 370mm it is green stated on mine. Just test it on the groundglas if you get it sharp with a loupe, but you need a bellows lengs from about 300mm. Otherwise take it with the 180mm just with shoulders not only the head then it should be okay with 180mm almost. Don`t forget the different F stops if you only need the back elemnt. The other idea is take the front element alone and check it also thies way.In may case I still did not test it with the front element alone, but I`m quite sure it works also with my older one. Best you trie all versions then you know it, and let me know to!
Good luck and good light!
-- Armin Seeholzer (firstname.lastname@example.org), August 08, 2001.
unless you need to fillyour format (slides for viewing .....or something like that), it is a lot better to crop your image and let the lens alone (Armin is right it is the front element you should remove.....)the lens performs as a longer lens allright but with a tremendous loss of quality, enlarging is a better option. Most portraits on large formats are done with shorter lenses than the small format, for a number of reasons....
-- andrea milano (email@example.com), August 09, 2001.