View Full Version : lens troubles

07-15-2006, 12:45 AM
so i am not very knowledgable about lenses,
i have a 5x7 field camera that i am converting to 4x5, to get a focused immage my camera must be closed as far as it can go... i get nothing near focused with any bellows extension... even with close up shots.
is it my lens? what should i look for if i need a new one.

the lens says kodak no. 1 kodamatic (or is that the shutter)
on the inner ring of the lens it says it is a kodak anastigmat 103 mm


07-15-2006, 02:15 AM
Is it a very thick camera? With that lens the image should be in focus when there is roughly 103mm (4") between the lens and the film plane for a distant subject.

As the subject gets closer, the lens-to-film distance should increase, the infinity-focus distance is the shortest. If you are shooting something quite close to the lens (as in macro), you might need several hundred mm of extension.

Are both parts of the lens present? There should be glass both in front of and behind the shutter blades.

07-15-2006, 05:38 AM
the lens will not cover the entire 4x5 film either. The edges will be black. I think you will have to search for another lens, that will also solve your focussing problems. The standard lenses for 4x5 are 150mm - 180mm. This will give you more or less the same as a 50mm lens on 35mm film.

07-16-2006, 07:44 PM
Actually, Wimpler, depending on the actual lens, some lenses in the 103-105 mm range will (barely) cover 4x5. I've got a 105 mm f/4.5 Agnar that, I've recently discovered, will cover 4x5 with slightly soft, but fully illuminated corners, as long as I stop down to f/22 or smaller. The Kodak Anastigmat is a similar triplet -- it might well do the same.

However -- 103-105 mm is pretty short for conventional 4x5 cameras and doubly so for a converted 5x7 ("normal" for 5x7 is about 210 mm and there's little expectation, in designing one, to need to focus with lenses under about 135 mm); I'd suggest looking around for an inexpensive 135-150 mm lens to supplement that one. You'll get more coverage (though possibly not much more, depending on the lens design you wind up with), and less "wide" feel to the images (105 mm on 4x5 is roughly like 35 mm on a 35 mm camera).

07-19-2006, 01:03 PM
Is it a very thick camera? With that lens the image should be in focus when there is roughly 103mm (4") between the lens and the film plane for a distant subject.

Some very good points are made above. If you want to experiment further using your lens, you might want to consider constructing a recessed lens board (this could help focusing issue, but will not improve coverage area). This would place the lens closer to the film plane and allow for some bellows extension equal to the amount of recess of the lens board. There are limitations to how deep you can go considering basic things like attaching cable release and setting lens to limiting the coverage of the lens. Attached is page with pictures of recessed lens boards.


07-22-2006, 02:45 PM
...nobody knows the lens trouble I've seen..

nobody knows mah sorro-w-wo-wo..