Bayonet system for lenses

[Daniel Stone]

Does anyone know of a bayonet-style system for LF lenses?

I'm thinking of this:
Compound 5/Ilex #5 shutter used as a "universal" shutter, with multiple lenses
Each lens has a "bayonet" mount attached to it, and the shutter has a corresponding "mount" similar to a 35mm/MF style bayonet mount. Something very simple.

My reasoning:
I have this 11x14 Phillips, as many of you know. Since no one wants to buy it, I figured I'll keep it and use it :D.
So I'm looking at lenses. Process lenses primarily(keep my budget in check!). Artars, Ronars and Ektanons. But I looked at the Sinar shutter system, and with those hard-to-get cables, I'm thinking that using a large shutter like an Ilex or Compound #5 would be best.

ideas/sources of anyone(worldwide is fine) that could do top-notch work like this? I'm thinking of hiring someone to draw up some plans on 3d software, so that a machine shop could make a system on a cnc(for exacting accuracy/repeatability between everything). SKGrimes can probably do it, but I'm open to alternatives as well.
I'm in no rush to do this, as I'm moving come the new year

Right now I'd be starting with 1, maybe 2 lenses. A 19 3/4 Ektanon is looking like a good-to-go, but open to Artars and Ronars(since I've got past experience with them)

If anyone else would be interested in this, I'd imagine it'd bring the price down a bit on each one, since multiples would be made.

thx,
Dan

[MichaelRelguag]

Have a look at a Voigtländer Bergheil - they had an interchangeable lensmount system for the 6,5x9cm and 9x12cm cam.
I get mine this or next week, then I will show some pics.

[Vaughn]

Interesting. The thing one has to deal with with front-mounting lenses onto shutters is vinnetting (sp?), especially with shorter lenses. Another way would be a combo of a Packard shutter and one of those adjustable iris thingies that clamp onto barrel lenses. Packard on back of the lens board, the iris thingy on front of the lens board.

[Bob Salomon]

There was one made twenty or thirty odd years ago in Cleveland, TN. Never caught on, believe there was a parallelism problem with it.

[jp]

To keep things simple, I'd suggest you have thread adapters made to screw the lenses into the compound5 shutter. It'd be simple and cheap one-piece metal. The only advantage of a bayonet system would be exact rotary positioning you won't get with the thread adapters. That shouldn't be a problem with LF, but with 35mm, the positioning is needed to make sure electrical contact line up, stop-down lever lines up, proper F-stop shows up in the pentaprism, that sort of thing.

[Steven Tribe]

I have suggested this be moved to the correct forum!!


"Compound 5/Ilex #5 shutter"
These are not really readily available in large quantities. And really not that big an aperture for many classic lenses covering 11x14".

[IanG]

Interesting. The thing one has to deal with with front-mounting lenses onto shutters is vinnetting (sp?), especially with shorter lenses. Another way would be a combo of a Packard shutter and one of those adjustable iris thingies that clamp onto barrel lenses. Packard on back of the lens board, the iris thingy on front of the lens board.

You'd go Packard and I go Pickard :D a large TP shutter with interchangeable lens boards will cope with almost all lenses and give a reasonable range of shutter speeds T and I 1/10th - 1/90th. Alternately a range of 3 or 4 front mounting TP shutters would cover a very wide range of lenses.

Ian

[Dan Fromm]

Dan, I do something similar with my process lenses. I have only one great long one that's absolutely unusable hung in front of a #1. All of the others screw into cup-shaped adapters that screw into the front of a #1. A number of the shorter ones have the same mount threads so I have fewer adapters than lenses to screw into them.

As for the monster, a 900/10 Apo-Saphir, I have an industrial Compound #5 with no diaphragm that screws into a cup-shaped adapter that slips onto the front of the lens' barrel.

If you check with a machinist, you'll find that bayonet mounts cost a lot more than simple threaded bushings. And that's what my cup-shaped adapters are.

About hanging lenses in front of shutters. There are two limiting factors, vignetting and loss of diaphragm control.

Vignetting isn't as big a problem as people think, the trick is to position the shutter as close to the back of the lens as possible. I use a simple geometric model (similar triangles) to see in advance how bad vignetting will be. The diameter of the unvignetted circle is given by (distance from lens' exit pupil to film plane) *(obstruction's diameter)/(distance from lens' exit pupil to obstruction). In this case the obstruction's diameter is the diameter of the shutter's opening, wide open. For convenience I assume that the exit pupil is at the diaphragm. So far this model hasn't led me over a cliff, in fact is is a little conservative. It predicts vignetting with a 480 Apo-Nikkor on my little 2x3 tandem Graphic and there is none.

Loss of diaphragm control is something else again. With the shutter close to the rear of the lens, reducing the size of the lens' exit pupil by stopping down will have no effect on illumination on the film plane until the exit pupil is smaller than the shutter's diameter, wide open. This can be limiting. My 900 Apo Saphir doesn't vignette on 2x3 in front of a #1, but its diaphragm has no effect until around f/32. With a Compound 5 in front of the lens, its diaphragm starts to have the desired effect midway between f/11 and f/16. Not ideal, but I can live with it.

Hanging a heavy lens in front of a shutter will require a crutch to support the lens. You may be better off hanging a light shutter in front of a heavy lens.

If you want to learn more about front mounting and the troubles I've see, read http://www.galerie-photo.com/telechargement/dan-fromm-6x9-lenses-v2-2011-03-29.pdf for a longer discussion of front-mounting and http://www.galerie-photo.com/baby-bertha-6x9-en.html for a longer discussion of the difficulties front-mounting got me into.

Short version, what you want to do is quite feasible. You may or may not need a shutter as large as a #5, depending on the lenses you want to use. And threaded stepped bushings are the way to go, bayonets cost much much more.

Cheers,

Dan

[Daniel Stone]

hey guys,

thanks for the info.

I like the ease of use of the Ilex/Compound shutters, especially the compounds(my absolute, hands down favorite shutter ever, VERY quiet!)

I'm looking to start with a lens in the ~20" FL range. A wider(12"?) lens down the line might be added, but for now a 1-lens system that can handle full-length portraits (in studio, a project I want to shoot in the next year or two). Thinking something lighting-wise similar to Irving Penn's picture of Marlene Dietrich:

http://2.bp.blogspot.com/-RDYN5lm8QEA/Twh4vcZqVtI/AAAAAAAAAsU/uOk96i70NDc/s1600/penn5.jpg

Most likely in the range of 20-30 full-length portraits, with some closer-up pictures as well(not for all, maybe 1/2, really good friends and/or family members)

This would be a "balls out" financially project, hence saving for 1-2yrs before doing it(think studio rental, a friend as an assistant), stylist, full thing). Being an assistant for a few years has taught me more than just how to schlep power packs ;)!

The "other option" would be to get a Fuji 600C, seeing that I have 28" max of bellows to stretch, but I believe a 20" older(single coated) lens would probably have less inherent contrast, and for my intended purposes, will probably be better than the latest multi-coated options like the Fujinons(which I love for 5x7 and color shooting!)

-Dan

[Daniel Stone]

I have suggested this be moved to the correct forum!!


These are not really readily available in large quantities. And really not that big an aperture for many classic lenses covering 11x14".

hence my looking for a really clean one :)

[Steven Tribe]

There was a nice one (Compound 5, 10-1) that ended on French ebay just two days ago!

231080517756

[Dan Fromm]

Industrial shutter without diaphragm, Steven, just like the one I bought some years ago via leboncoin.com.

[jcoldslabs]

Dan,

You may have already mapped this out in terms of measurements, but I just checked and the rear diameter of my 21 1/4" copying Ektanon is somewhat smaller than the threads on the front element of my 12" f/4.5 Ektar in an Ilex Universal No. 5, so it appears your plan has the potential to work with the Ektanon/Ilex No. 5 combo. With the right adapter you could position the rear element as deep into the front of the shutter as is physically possible which might help mitigate some of the concerns Dan Fromm raises about vignetting and exit pupil size.

Jonathan

[Dan Fromm]

I neglected to mention another reason for mounting the shutter in front of big fat lenses. A lens that's bigger than the shutter mounted in front of the shutter will obstruct access to the shutter's controls. This is an especially bad problem with dial set shutters such as Compounds.

By the way, if it isn't clear, I've done all that the OP wants to do except take soft-focus portraits. I haven't reported "concerns," I've reported practical problems of implementation. Been there, done that, have a reasonably good sense of what's possible.

[Daniel Stone]

I neglected to mention another reason for mounting the shutter in front of big fat lenses. A lens that's bigger than the shutter mounted in front of the shutter will obstruct access to the shutter's controls. This is an especially bad problem with dial set shutters such as Compounds.

By the way, if it isn't clear, I've done all that the OP wants to do except take soft-focus portraits. I haven't reported "concerns," I've reported practical problems of implementation. Been there, done that, have a reasonably good sense of what's possible.

thing is, I <DO NOT> want to take soft focus portraits, in focus all the way, just soft, relatively easy-on-the-complexion lighting :)

hence why I'm interested primarily in process lenses, which as most of us know, were designed for SHARP results :D

[Bill_1856]

My Dr. Stable Polyplast casket set has four (4) front elements which bayonet onto a small Compound shutter, giving 105, 135, 165, and 195mm focal lengths (each with its own aperture scale). Used without front element, the (fixed) rear element alone is 230mm. It is a really marvelous arrangement; the only drawbacks seem to be a focus shift of about up to 1/4" on stopping down, and of course they are uncoated and get progressively slower with increasing focal length.
They are reasonably sharp for a pre WW2 design, probably about like a Protar.

[EdSawyer]

I have a big Fairchild Rapidyne Day Shutter, electrically controlled with various speeds. The lens cells threads are 3.5" diameter, so it can handle a pretty huge set of cells. It had a 12" f/4 aerial lens in it, so it's not a small piece. It can be triggered manually or electrically, and probably cost the military thousands of $. It's up for grabs if someone can use it... (comes with a lens cone too...) Just a random thought.

[Drew Wiley]

The last bayonet system for LF I remember looked like the little tabs would just wear out prematurely. And the amt of time you'd save changing lenses would be
inconsequential. The marketing point was that each bayonet adapter would be more compact than a conventional lensboard. But we can simply do that with adapter boards. And bigger lenses just wouldn't fit anyway.

[Oren Grad]

It's very hard to find now, and I imagine it wouldn't be much help for the sort of focal lengths you're talking about - the barrels are likely too big. But FWIW, Horseman used to offer a bayonet system with bayonet rings to fit #0 and #1 shutters and a matching bayonet lensboard in standard Sinar/Horseman view size - which is, of course, just right for a big Phillips! :)

[Daniel Stone]

It's very hard to find now, and I imagine it wouldn't be much help for the sort of focal lengths you're talking about - the barrels are likely too big. But FWIW, Horseman used to offer a bayonet system with bayonet rings to fit #0 and #1 shutters and a matching bayonet lensboard in standard Sinar/Horseman view size - which is, of course, just right for a big Phillips! :)

Nice thought, but I'm not much into shooting macro with shorter FL lenses to increase coverage on larger formats than they were originally intended for :)

A 480mm Plasmat might fit into my future though, if one comes along that's within budget. Ya, it's the total opposite of the spectrum from what I originally thought about, but what the heck, why not? Especially if I can get my mitts on some 11x14 color film(like the co-op that Keith Canham is organizing RIGHT NOW for 11x14 Ektar 100 ;))