Filter behind the lensgreenspun.com : LUSENET : Large format photography : One Thread
Other than the hassle, is there any reason why placing a filter behind a lens would result in poorer performance compared to placing the filter in front of the lens? I guess the image circle may be reduced more, but let's ignore image circle issues for the purposes of this discussion.
Why don't manufacturers provide threads or an easy way to put on resin filters behind lenses? Heliopan makes an adapter that "clamps" on to lenses without threads, so filters or resin holders can be attached. Has anyone tried this? I thought that this was the main purpose for this adapter, but Bob Salomon tells me otherwise. Actually, Lee also makes a filter holder with two "rubber bands" for attachment.
Taping resin filters to the back of my lenses seems too dirty for me.
-- Carlos Co (email@example.com), March 06, 1999
Of course, I don't intend to use grads, polarizers, etc. behind the lens. These go to the front. Only CC filters go to the back.
-- Carlos Co (firstname.lastname@example.org), March 06, 1999.
I have taped filters for many years-I use four peices of tape foled into a circle- works great-
-- Richard (email@example.com), March 06, 1999.
This technique works great, especially if you are use gels or resin filters. It reduces flare/reflection problems to near zero. I use phototape or gaffer tape that leaves little residue on filter or lens barrel.
-- Ellis (firstname.lastname@example.org), March 06, 1999.
What I told you was that placing filters behind lenses results in a focus shift of 1/3rd the thickness of the filter.
Except for some gel holders there are no behind the lens filter holders for this reason and also because any dust, dirt, fingerprints, scratches, uneveness in a filter (glass or acrylic) will materially effect the image.
The Heliopan adapter was desined to put filters on to the front of lenses without thr
-- bob salomon (email@example.com), March 07, 1999.
Yes Bob, you absolutely right! This why Sinar built a 100mm filter holder into the rear of both the auto & digital shutters.
-- Ellis (firstname.lastname@example.org), March 07, 1999.
Yes they did. And Xenophon Beake makes a holder too. For gels.
-- bob salomon (email@example.com), March 08, 1999.
I have a schnider 300 f:5.6 APO and what I have done is this. You use a coken pro size filter holder. For this lens I needed to cut the hole out a little and then I glued it to the metel parts on the rear of the lens with black silastic cement. This way if i choose to remove it it will not be difficult to do so. I then use the lens cover that comes with the cokin holder. I also use A pol. filter on the rear and in order to this i just view through the rear of the lens with the filter on and rotate the filter till the seen looks as I want.
-- Dan Jackman (firstname.lastname@example.org), July 24, 1999.