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ondebanks
4-Feb-2011, 16:28
'Evening all.

I just saved this lens from ending up "in the skip" during a physics storeroom clearout in the university where I work.

It's an impressive item to say the least!
I measured it as follows:
Front element clear diameter = 85mm
Rear element clear diameter = 59.5mm
Weight = 2.1kg / 4lb 11oz

The construction is beautiful and so solid; for example there is a knurled brass rear ring which turns smoothly to lift out the rear cell. The barrel is mostly smooth chrome (89 mm diameter) and the front is black-painted brass, with several identifying imprints in white on the retaining ring and the outer edge. These include the British and US patent numbers, which led me to a French webpage where the design is recreated from the patent (unfortunately I cannot find the page again, but I remember it was a 7 element design, double gauss-ish).

The optics are coated with several different reflection colours (various shades of pink and yellow/amber), so possibly multicoated. They are surprisingly clean, but not perfectly so. There is a maroon coloured rear lens cap, apparently made of cardboard with a leather-effect covering.

I held it up to some light sources and found that it projects a large sharp image, around 65mm behind the rear of the unit. It completely illuminates the 6x9 cm focusing screen reflex attachment of my Mamiya Universal, without any perceptible falloff. I suspect that it covers at least 6x12 cm if not 4x5 inch. This is exciting stuff! Could be the ultimate barrel lens!

I have an Ilex #5 shutter with an iris diameter of 63mm; not far off the rear element diameter of 69mm; might be worth an adaptation. Or there's always the Speed Graphic route, but I don't have one.

What really surprised me was when I held a telescope eyepiece behind it; I was expecting a soft chromatic image but instead I found that it was really well corrected for aberrations.

Any thoughts? Anyone ever see this lens before? Any idea of its worth?

Ray

Dan Fromm
4-Feb-2011, 18:08
Y'r lost French site might be www.dioptrique.info

ondebanks
5-Feb-2011, 03:43
Hi Dan (long time since we chatted about fast aerial lenses!),

Ah yes - www.dioptrique.info, that's the one - thanks.

So this is the design (Brit. patent 522651): http://www.dioptrique.info/OBJECTIFS19/00939/00939.HTM
That's for a 100mm f1.4 lens specified for 40 degrees...mine is a 127mm f1.5 lens with presumably the same 40 degees coverage.

I'm just astonished at the size and speed of the thing. I used be envious of folks who had a 98mm f1.4 Wild Falconar; now this 127mm f1.5 Taylor Hobson falls into my lap! It's crying out for a test on a camera, but I'll have to come up with an adapter first.

Cheers,
Ray

Dan Fromm
5-Feb-2011, 06:26
Ray, I used to want a 98/1.4 Falconar. And then I bought a collection of USAF lens datasheets in .pdfs from someone via eBay that included one for it.

Back focus 1.71", barely covers 6x6, AWAR wide open 25 lp/mm. From my narrow parochial perspective an answer looking for a question. I think I'm better off with my 4"/2.0 TTH. Given how and when and where I shoot, I'm usually even better off with a decent 4"/5.6 plasmat in shutter than with the TTH.

Eric's calculations make your treasure look appealing, but his estimate that it covers 40 degrees reduces the appeal a bit. At infinity that's 92 mm. Fine for 6x7, not for my 2x3. Again, I'm being narrow and parochial.

But seriously, how are you going to use it if it has no diaphragm? My two fastest lenses for 2x3 (that 4"/2.0 TTH, 100/2.5 Uran-27) both have diaphragms so can be used fairly easily on a 2x3 Speed Graphic. And how's the back focus? Lastly, what size of Graphic (or Graphic-like) camera do you have? I ask because the 2x3 Graphic's front standard is small and I've sometimes found it limiting.

Cheers,

Dan

Cheers,

Dan

Mark Sawyer
5-Feb-2011, 10:02
I'd suggest breaking down and getting a 4x5 Speed Graphic, and find a 6x9 roll-film back for it. Anyone with 4x5 and smaller barrel lenses needs one!

ondebanks
6-Feb-2011, 10:36
Mark,

You may ultimately be right about the Speed Graphic, but I had another approach in mind which mainly utilizes components that I already have; if you'll read on...

Dan,

Here's what I aim to do. It will answer your questions about back focus, aperture control and so on. I'll give you the long preamble...

When I started building my Mamiya Universal kit 4 years ago, I was won over by its modular simplicity, and how it almost straddles the border with LF, with its size 0 shuttered Press lenses. The idea that other glass from a size 0 shutter could be mounted on it got me researching and tinkering; I acquired mechanically defective lenses, extension tubes etc. and in this way I remounted some excellent modern 6x6 Bronica glass (PS 80/2.8 and PS 65/4) into Press barrels/shutters, and squeezed some very nice 6x7-6x9 images out of them. This was really cool, and additional satisfaction came from knowing that I was probably the only person to have done it (or was crazy enough to have tried to do it).

So then I started looking at other opportunities to expand the coverage of my MF SLR lenses. Could I get 6x6 images from my fast M645 lenses, like my 80/1.9 and 200/2.8 APO? Could I get 6x7-6x9 coverage from my P6-fit 6x6 lenses, like my 30/3.5 Arsat fisheye and 300/4 Sonnar? (Indeed, could I even just get their native 6x6 coverage from them again, having abandoned Pentacon and Kiev bodies, mainly because of film flatness issues perceptible with wide open lenses?).

But none of these lenses are in shutter, nor did I want to dismantle them anyway. So, inspired by some designs I've seen with big barrel lenses, and the likes of Claudio Bottari's and Bob Hutchinson's creations built around Mamiya Press components, I sketched out a camera with the following parameters:

1) Film backs & Viewing screen:
Mamiya Press rollfilm holder (6x6, 6x7 or 6x9) + M-adapter
or
Mamiya Universal Polaroid back
and
Mamiya Universal P ground-glass & folding hood
[I had all of these, and they all attach to the Universal via its native "P" rear mount]

2) Body:
Custom thin square box, with P-mount rear fitting (the Universal body is too thick)
Ilex #5 shutter on front plate
M645 bayonet adapter screwed into shutter
[I initially had none of these]

3) Lenses:
Any M645
Any P6 with M645 adapter
[I had all of these]


Getting the body made with a P-mount fitting was clearly going to be tricky. But I solved the hardest part of this by finding the thinner of the two "rear spacers" that Mamiya produced for doing macro/copy work with the Universal. This basically is the thin square box I need, and it has the P-mount fitting! I later got the Ilex #5 shutter. This left 2 custom components to get machined; the front plate and the M645-Ilex adapter. For a long time, I dithered about their specifications, and who I should ask to do it, not knowing anything about technical drawing or machining. Then the next thing you know I "went digital" and got a used Kodak digital back for my M645, and spent the past year shooting digital MF a lot, and film very little. (Forum members are permitted to hiss angrily at my betrayal :o )

So that brings us up to the present. I now have this amazing 127/1.5 lens and it has the same sort of back-focus as the M645 lenses. It has a large internal rear thread, so it would be a very straightforward adapter to make between it and the Ilex #5 shutter. The Ilex solves the dual problem of this lens lacking both aperture and shuttering controls. So I just might restart that project again!

Cheers,
Ray

Dan Fromm
6-Feb-2011, 12:54
Ray, thanks for the explanation. I don't know whether you know it, but we're on somewhat parallel paths. Your really neat camera is based on a Mamiya Press. Mine, which also shoots 2x3, is actually a couple of 2x3 Graphics and a 2x3 Cambo SC. Details of implentation aside, we're both using lenses made for other purposes to shoot 2x3 and we're both doing a lot of, um, adapting.

I think I may be a little ahead of you. At any rate, I've had a bit of experience with front-mounting and doubt that y'r Ilex #5 will function as an aperture as well as a device that times exposure with y'r TTH monster. I've put lenses as short as 4.75" and as long as 610 mm (900 mm when the bits come back from the machinist) in front of #1 shutters. Vignetting has not been a problem on 2x3 and the shutters haven't acted as apertures.

You might want to read about my lens adventures at http://www.galerie-photo.com/1-lens-6x9-dan-fromm.html , http://www.galerie-photo.com/2-lens-6x9-dan-fromm.html , and http://www.galerie-photo.com/3-lens-6x9-dan-fromm.html . These links are to the English text, there's also a parallel French text.

As you'll read, for the most part I've avoided lenses for formats smaller than 2x3 because of concerns about coverage. I have, though, wondered what the 30 mm Arsat would do on 2x3 and whether it could be stuffed into the front of a 2x3 Speed Graphic.

I've put lenses as short as 4.75" and as long as 610 mm (900 mm when the bits come back from the machinist) in front of #1 shutters. Vignetting has not been a problem on 2x3 and the shutters haven't acted as apertures.

I think you're going to have to have your TTH monster put in a barrel with diaphragm. The big questions about doing this have to do with how it was built and how much space there is between the inner doublets.

Construction issues. Lenses without diaphragms, e.g., the tantalizing and frustrating 40/5.6 S-Biogon, are sometimes built as staight tubes with the lens elements somehow held in place in them rather than as a pair of cells that screw into a shutter or barrel. That's putting a 40 S-Biogon in shutter is such a problem. Your TTH may be a nasty.

Spacing issues. One of my cutest little barrel lenses is a 100 degree (or 110 or 120 degree, depending on the vintage of the manufacturer's propaganda consulted, the older the wider) wide angle lens with wheel stops. There's not enough space between the cells to mount them in a plausible shutter, e.g., Ilex #3 or larger. With respect to your TTH, Eric's cross section is a little daunting. Against that, my 4"/2.0 TTH that I suspect Eric has analyzed (but which of the f/2.0s?) has a diaphragm.

Good luck, have fun, keep me posted on your progress,

Dan

ondebanks
9-Feb-2011, 06:11
Hi Dan,

I read all three of your pages on your lens trials and adaptations. Whew! Your publicising of this information must be a great resource to many people like myself.

I am just curious why you say that when front-mounting on a #1 shutter, "the shutters haven't acted as apertures", and in my case "doubt that y'r Ilex #5 will function as an aperture as well as a device that times exposure". I know that such an aperture placement would not be ideal, and it should really be around the centre of the lens between the groups; but even so, closing down the shutter's aperture must still throttle down the light? Do you mean that it has little effect on the effective f-ratio and just throttles up the vignetting (shrinks the image circle) instead?

"sometimes built as staight tubes with the lens elements somehow held in place in them rather than as a pair of cells that screw into a shutter or barrel. Your TTH may be a nasty."
- yes, that is the situation. The barrel is a smooth cylinder, into which the front and rear groups are threaded at either end.

"There's not enough space between the cells to mount them in a plausible shutter"
- not sure; there may not be. I didn't look at that aspect when I was measuring it.

But I am not really aiming to reconfigure the lens to the extent that the barrel is dispensed with and a shutter interposed between the two groups. I'd like to retain its current structure and just screw it into a large rear shutter. I might not even particularly care whether I can get it to stop down at all, or beyond say f/2. I am interested in this lens for its wide-open speed: maybe as a funky wide-field astrograph (remains to be seen if it is optically up to the job, but first impressions with the eyepiece were good). Once it is stopped down to f2.8 or less, then I can't see any advantage, as I already have f2.8 MF lenses between 100-150mm focal length, and a 135/3.5 LF Xenotar.

If it ends up being too tricky to adapt to the Ilex or M645, there's always the "easy" option - make a threaded adapter, with the lens rear thread on one side and a T-ring thread on the other; then T-mount it onto our EOS 5DII. 127mm f1.5 on a full-frame DSLR :cool: - and to think that Canon boast about their 135mm f2.0 being the fastest lens in this range!

cdholden
9-Feb-2011, 07:55
But none of these lenses are in shutter, nor did I want to dismantle them anyway. So, inspired by some designs I've seen with big barrel lenses, and the likes of Claudio Bottari's and Bob Hutchinson's creations built around Mamiya Press components, I sketched out a camera with the following parameters:

1) Film backs & Viewing screen:
Mamiya Press rollfilm holder (6x6, 6x7 or 6x9) + M-adapter
or
Mamiya Universal Polaroid back
and
Mamiya Universal P ground-glass & folding hood
[I had all of these, and they all attach to the Universal via its native "P" rear mount]



I don't have any view cameras or lenses that small, but I could suggest for others with a 4x5 that Cambo/Calumet offers the C2 & C2N 6x7 and 6x9 roll film holders. Also, Graphic/Singer with the 22/23 (6x7/6x9) roll film holders. Both of these are frequently available and inexpensive.
Chris

Dan Fromm
9-Feb-2011, 08:10
I am just curious why you say that when front-mounting on a #1 shutter, "the shutters haven't acted as apertures", and in my case "doubt that y'r Ilex #5 will function as an aperture as well as a device that times exposure". I know that such an aperture placement would not be ideal, and it should really be around the centre of the lens between the groups; but even so, closing down the shutter's aperture must still throttle down the light? Do you mean that it has little effect on the effective f-ratio and just throttles up the vignetting (shrinks the image circle) instead?

Exactly. All that making the shutter's aperture smaller accomplishes is shrinking the circle covered.


"sometimes built as staight tubes with the lens elements somehow held in place in them rather than as a pair of cells that screw into a shutter or barrel. Your TTH may be a nasty."
- yes, that is the situation. The barrel is a smooth cylinder, into which the front and rear groups are threaded at either end.

Then it might not be a nasty. If each group can be unscrewed as a unit you're ok. I was talking about lenses whose elements are held in place in the barrel by rings and aren't organized into groups that can be removed as a unit. But if there are cells that can be removed as units then there's the chance of putting the cells in a barrel that has an iris. Go check what Edmund Industrial Optics offers in the way of barrels with irises.


But I am not really aiming to reconfigure the lens to the extent that the barrel is dispensed with and a shutter interposed between the two groups. I'd like to retain its current structure and just screw it into a large rear shutter. I might not even particularly care whether I can get it to stop down at all, or beyond say f/2. I am interested in this lens for its wide-open speed: maybe as a funky wide-field astrograph (remains to be seen if it is optically up to the job, but first impressions with the eyepiece were good). Once it is stopped down to f2.8 or less, then I can't see any advantage, as I already have f2.8 MF lenses between 100-150mm focal length, and a 135/3.5 LF Xenotar.

If it ends up being too tricky to adapt to the Ilex or M645, there's always the "easy" option - make a threaded adapter, with the lens rear thread on one side and a T-ring thread on the other; then T-mount it onto our EOS 5DII. 127mm f1.5 on a full-frame DSLR :cool: - and to think that Canon boast about their 135mm f2.0 being the fastest lens in this range!

Thanks for the further explanation, I see that I hadn't fully understood what you had in mind. I'm glad you're skeptical about the benefits of using a big heavy fast lens at a small aperture when perfectly good smaller and lighter lenses that work well at the small aperture are on hand.

Cheers,

Dan

Math
15-Nov-2011, 09:18
Check into a Mamiya Super 23: They have bellows rear for tilt, but which could also be used to focus. This way you could mount the lens fixed.