using 35mm lens with LF system

[songster]

I am interested in adapting lenses for 35mm systems for use with a LF system. The reason for doing this is, well in addition to finding myself a little project, I thought it might be interesting to get a circular image projected by 35mm lenses onto roll films (4x5 not necessary as the image circle usual won't exceed 55mm diameter). Mounting the lens should not be difficult; take the lens mount from a broken camera, screw it onto a lensboard of choice.

However, as for the shutter and the short distance between lens and film necessary to focus at infinity, I am at lost as to what the best solutions might be. Any suggestion, experiences welcome. Thanks in advnace.

[Roberts]

So, what do you mean by LF?

Don't waste time to do so!

And don't pollute the World by processing films shot by this combination!

[songster]

Thanks, Kevin, for your reply. What I meant by LF is what I thought this forum is design to discuss. I do currently use a monorail in studio, and for outdoor applications, I use a modified Super Graphics (range finder removed to reduce weight and bulk). Occationally 4x5, but mostly with 23 back for convenience. Therefore, adapting for the above setups may not be all that difficult as long as I can get the lens close enough to the film plane.

Could you please elaborate on why you think it's a waste of time to do so? Is it because you think/know the quality will be so poor that it's not worth doing, or is it because the resulting image does not suit your style. Judging by your reply, it seems it has to be one of the above reasons.

Or perhaps there are easier ways that it's not necessary to go through all the trouble. If so, what might they be?

If there is a more appropriate category, or other forums, for posting this question, could you please point me their ways.

Thanks.

[Mark Sawyer]

Songster-

I played with this thirty years ago, and offer the following:

For my purposes, I used a slow film and neutral density filter so the exposure was long enough to use a lenscap as a shutter. A better approach would be a press camera with a focal plane shutter.

If you're handy, build a recessed lensboard if you need it to move the lens closer to the film plane, but on my 4x5, a flat one was sufficient.

With the round format, I found a short focal length lens gave an exagerated sense of space that went nicely with the circular image. As 35mm lenses all mount at the same place on their intended camera body, the distance from the rear of the lens to the film plane won't change much. (They're mostly retro-focus or telephoto or genetic mutants...)

[Dave Moeller]

Might be fun for macro work. Dim as all get-out, but fun nonetheless. If you move any lens far enough away from the film, you'll fill the entire frame with an image.

If you're shooting with Nikkor glass, I believe one of the 28mm lenses (perhaps it's the f/2) projects a circle large enough for 120 film. Getting image circle data on 35mm lenses has proven to be singularly frustrating in the past...this might be a case where it's best just to try what you have with a temporary lensboard to see what you get. If it was me, I'd probably make a lens board out of thin plywood and mount the 35mm lens to the back of the board (a step-up filter ring and some gaffers tape should handle this just fine)...with the body of the lens behind the board you'll have less need for a recessed lens board. Just make sure you can move the front standard far enough away that the rear of the lens doesn't get all of the way to your film plane. No need to scratch up your ground glass with an experiment.

[John Layton]

This won't help for infinity focus - but years ago, I reverse-mounted a 55mm Micro Nikkor, using a filter ring (no glass) set into a homemade lensboard and mounted this on my Crown Graphic. I then cut a hole in the rear lens cap and mounted a shutter into this, then mounted this shutter to the rear of the lens. I got some fantastic full frame 4X5 images with this setup - in the 5 to 10X magnification range.

The problem you face at infinity with lenses designed for 35mm is back focus as you mentioned. perhaps you could "reverse mount" a lens by its filter threads to the inside of the lensboard, so the lens would face forward from inside the board and thus shorten the distance to the film. you could then either mount a packard shutter to the front of this, or perhaps even a big old Ilex, by its inner threads to the female side of a filter ring affixed to the front of the lensboard. Good luck! (I just love trying to figure out stuff like this!)

[Matt Mengel]

If you try mounting a 35mm lens (or anything for that matter) inside your bellows as John suggested make sure you dont smash your ground glass as you cant see what's in there.
Also-Nikon actually made a 35mm back for 4x5, sort of the same idea in reverse.

[Randy_5067]

songster

If you do go ahead and attempt, keep posted as to how it turns out. I have often wondered the same thing. I have a ton of 35mm lenses and have often wondered what kind of image I could get on my 5x7's. I thought if nothing else, the vignette effect might be different. Or if a long exposure with the lens reversed???? Kinda sorta more or less but maybe not really like a pinhole effect? Never know till ya try, I guess.

[Dan Fromm]

More-or-less the longest flange-to-film distance is of any 35 mm system is Nikon's 46.5 mm. Kinda limiting for mounting any lens for a 35 mm system in front of a shutter on a larger camera.

T-mount f-to-f is 55.0 mm. Still too short to make infinity on a Mini Speed Graphic, even shorter for a 2x3 Pacemaker Speed. 4x5 Speeds are bigger still. So much for a press camera with a focal plane shutter.

But you could probably mount a not too long not too fat lens for a 35 mm camera behind a 4x5 Pacemaker board and stuff it through the lens throat. Lens throat diameter, which I don't know, is limiting. FWIW, the 2x3 Pacemaker throad is 48 mm square.

I shoot a reversed 55/2.8 MicroNikkor AIS in front of a Copal #1 on my 2x3 Pacemaker Speed from 2:1 to 4:1, that's not what you want.

On the whole, another intriguing idea that seems hard to reduce to practice.

Good luck, have fun,

Dan

[Ralph Barker]

If it's just the round image you're looking for, y0u might consider lenses from old medium-format folding cameras as an alternative. Their longer focal lengths will give more room to work with.

Or, you could simulate the whole circular-image thing by using a black card vignetter, perhaps with diffusion around the outer edges. A bit of 1/4" bubble wrap with a central hole does wonders for softening the image when rubber-banded over an otherwise sharp lens.




bubble wrap over a Schneider APO Symmar 150