Wollensak Dumont Cro 50 MM f/1.5 Raptar

[quincy]

Hey guys,

 

last week I got a vintage lens (by chance). It's a Wollensak Raptar 50mm f/1.5.

 

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I've started reading a bit about the company (located in America) which was building lenses from 1902 to 1972 in rather small numbers, and the raptar seems to be one of their more uncommon lenses.

The lens itself is in very good shape. No scratches, neither on the body nor the glass, no fungus, not much particles inside (actually i can only see three small dots that shouldn't affect image quality at all). It was a bit dirty on the outside, but after cleaning it looks like new. The aperture looks good, has 15 blades, does not stick and is easy to move. I've already done some test shots with the lens hand-held in front of the camera. The results look promising, apart from the boring subject and the light leaking through my fingers onto the sensor, reducing contrast.

 

So I'd like to adapt it to X-Mount. And here comes the first problem: The lens itself does not have a focusing mechanism. I think I can solve the problem by using one of these adapters: http://www.kipon.com/en/articledetail.asp?id=76 They have a built in helicoid that can move the lens up to ~10 mm away from the "infinity focus" position, so I should be able to focus closer. It won't be macro, but at least a "normal" range, I hope.

 

However, I didn't find a solution for the second problem myself: I don't recognise the mount of this lens. I've got a picture attached below. The thread seems to be about M41. It's definitely NOT M42, I've tried that already. Does anyone know what mount this is, and what flange focal distance it has? Because only by knowing the flange focal distance, I can modify one of those Kipon adapters (probably the M42 version) to accomodate the lens. Any help is appreciated.

 

[milandro]

Isn’t this an enlarging lens?

 

I’ve had a couple of Wollensak and they were enlarging lenses in origin. That explains why it has no way to focus it (and it is really corrected only for short distances and won’t have any color treatment). I’ve also had one on a view camera but it was many years ago.

 

If, as I believ, this is an enlarging lens, the thread is most probably 39 x 1 adapters are available to bring it up to 42 x 1 and that would fit an helicoid adapter 42 x 1 > Fx.

 

I have one and use it.

 

Edited July 5, 2017 by milandro

[quincy]

Hey milandro,

 

thanks for writing!

 

I also at first thought it might be a projecting or enlarging lens, but the wollensak lenses i found that are built for enlargers have written "ENLARGING RAPTAR" on the front ring. Maybe they left that off in later versions?

 

I'll measure the thread again, and then I'll try the M39->M42->helicoid->fx adapter combination.

[Chucktin]

An f/1.5 enlarging lens? I don't think so.

 

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[milandro]

I am quite positive this was either an enlarging lens or a lens specifically made to be mounted on a macro bellows for reproductions.

 

Anyway, regardless, the only way to use it is to get an adapter such as the one that I’ve suggested.

 

This people might be able to shed light on this.

 

https://www.westechoptical.com/blog/the-wollensak-optical-company

Edited July 6, 2017 by milandro

[Alex Cremers]

Whatever it is (ciné or enlarger), they once asked more than 500 Euro for this lens on Ebay. And judging from photos of a Wollensak 50mm 1.5 on flickr, it bubbles and swirls like you wouldn't believe.

Edited July 6, 2017 by Alex Cremers

[milandro]

there are all numbers of people asking all kinds of weird money for all kinds of weird things on internet.

 

It is not made of gold nor it is an historical and legendary lens. I have bubbles and swirls for a lot less.

Edited July 6, 2017 by milandro

[Alex Cremers]

All I'm saying is, if you happen to get one by chance (like the OP), do not hesitate!

[milandro]

I won’t, but wat are the odds?

[quincy]

Short update:

 

I've ordered the Fotodiox M42-FX helicoid adapter and a M42-M39 ring. however, the M39 thread does not fit. Neither can I put the lens into the helicoid adapter, it's too tight inside. So it's neither M39 nor M42. Any Ideas?

 

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By the way: I've unscrewed the front part of the adapter with the M42 thread on it, and its connected to the inner part of the tube. So if I get myself a replacement for this part (manufactured), I should be fine (if the flange focal distance of this lens is the same as M39/M42).

 

 

[milandro]

M stands for metric but this being what it is might be not metric but withworth 

[mario santos]

M41 lenses are lenses from medium format cameras like the reflex korelle, but your lens appears to be a projection lens. I just bought one The tessar 80mm 2.8 in that mount and want to make the same adapting. They have a focal distance diferent to other M42 lenses and you must make experiments to see whats the best distance using the helicoid. I dont have the lens yet but i guess the first try however would be to surrond the mount with tape and fix it to the m42 adapter and focus on the lens at infinity to see if it reaches infinity on the camera. next would be to see which is the minimum focus distance compared to the scale on the lens (m). From that info you should be abble to position the lens with the helicoid and then block the helicoid at that point and focus only with the lens.

Here is a link for a guy selling one like yours adapted to M42:http://www.ebay.ca/itm/Ex-Wollensak-Raptar-50mm-f-1-5-Modified-to-M42-X00648/282365029167?_trksid=p2047675.c100623.m-1&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20160608112848%26meid%3D159db3eba68f41b68ae025d185b5cd7d%26pid%3D100623%26rk%3D4%26rkt%3D6%26sd%3D311540794753

 

for the ridiculous amount of: 1490USD

Its just a small tube inserted on the back maybe 2-3cm

US $1,490.00

[milandro]

why would a projection lens have an aperture?

[quincy]

Hey milandro,

 

it is indeed the imperial whitworth system. I got myself a whitworth thread template and measured it. It's a 1 5/8 inches thread with 30 turns-per-inch (and I found someone who probably can build me a replacement for the inner part of the tube. We already have the right threading dies, now we need an additional gear for his lathe.)

 

sooo... maybe at the end of the week...

 

 

 

 

Hi mario,

 

thank you very much for your input! The lens itself does not feature a focusing mechanism and no focus scale, but the macro adapter should be able to take over this part (i hope). You are right, I need to check the infinity focus. as long as it needs to be further away than the minimum lenght of the adapter I'm fine.

Those prices seem to be normal for this lens. All I found were sold for ~$500 unadapted and damaged, the pristine ones started at about $1000, and the adapted ones start at $1300. I have no Idea what's so special about this lens apart from it being a bit rare, but maybe we'll soon see some images

[tobymarshall]

There were at least three versions of this lens, starting with the 50mm f1.5 Anastigmat, then the Raptar and Oscillo Raptar, which was, I believe 51mm. All these lenses were intended for scientific purposes, mostly for capturing CRT traces on oscilloscope tubes. There are quite easily adaptble by wrapping PVC electrician's tape around the rear barrel and inserting via friction fit into an M52 helicoid. Here is a shot with the 50mm f1.5 anastigmat

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