What the heck IS this thing ? 200+/f/5 lens

luisalegria · Expire: 2018-01-18

Mystery lens !

Having a taste for both the cheap and bizarre, I could not resist buying this strange lens for a nominal sum.

I mounted the whole thing in an M42 T-mount, and I can almost get to infinity. It looks like its a little longer than 200mm, and stops are marked from f/5 to f/22. It focuses from just short of infinity (on a Pentax) to about 9 feet/3 meters. There are no markings other than "Accura" on the barrel section near the mount.

What on earth is it ?

Some facts - on the camera end it actually has an Exakta mount, broken but recognizable. Connected to the Exakta mount is a focusing extension tube, marked "Accura", in the M40 thread typical of Exakta extension rings. I know this because it matches my Extakta macro set. You can use the focusing extension tube as a focusing helical. I got the thing assembled this way, I didn't rig it. I happen to have an M42 Accura focusing extension tube also.

The lens tube is just a conical aluminum tube, with the only glass elements in the very front, and I think there are only one or two elements, in front of the diaphragm. The diaphragm seems to have been added on, the f-stops are just scratched on the tube.

I think someone just made a lens for his Exakta out of various parts - I'm guessing that he machined a tube out of aluminum, cut a slot for the diaphragm peg, put in a diaphragm and lenses, and attached the whole thing to an Accura extension tube. Voila, a lens.

It works - f/5 ISO 200 hand held -

poilu · Expire: 2019-08-29

superb portrait Luis! a beauty

blende8 · Joined: 29 Sep 2007 Posts: 260 Location: Bremen, Germany

Very probably a prototype!

Mr. Green

luisalegria · Expire: 2018-01-18

Accura was the trade-name of a Japanese photo products distributor, they sold all sorts of accessories like filters, tripods, extension tubes, flash guns - and lenses, on which they put their brand name.

They were pretty much in the same business as Spiratone. I think the only unique product they had was a reflex housing for Canon and Leica, their own version of the Visoflex. And even that may have come from some other source. When I saw this thing the first time I thought it may have been a lens intended for Visoflex, for that reason. If so, it would have been quite rare. But no, it is even stranger than that.

Which is why I think the focusing extension tube on this thing is just one of these components, and Accura has nothing to do with the lens.

It doesn't look like a prototype, it looks like someone with a lathe made his own lens. And its a pretty good lens ! God knows where the glass and diaphragm came from.

Since it came to me from Pennsylvania, I'm now going to call it a "Penntar".

luisalegria · Expire: 2018-01-18

It behaves like a very simple lens, which it is of course, just one or perhaps two (cemented?) elements. Sharp in the middle, soft and full of aberrations away from center, particularly when wide open. But then, this has some value as a "pictorial" lens, doesn't it ? It is however fairly sharp (at the center) even at f/5

The bird -

100% crop -

Richard_D · Joined: 21 Oct 2007 Posts: 2378 Location: Faversham Kent UK

I'm amazed at the quality these simple optical designs can produce.

Farside · Expire: 2013-12-27

I'd imagine whoever cobbled it together was quite pleased with the results. I wonder what it cost him in parts?

DSG · Joined: 04 Mar 2007 Posts: 544 Location: London, UK.

I'd hazzard a guess that he was perhaps an engineer that was desperately after a sharp lens with good bokeh and because he could'nt find, or perhaps afford, a commercialy available lens for the job he decided to make his own out of bits and bobs from cheap lenses he perhaps bought on ebay?
Who knows?...All I know is that lens seems to have very nice bokeh. Very Happy

Ballu · Posted: Tue Sep 30, 2008 5:48 am Post subject:

This is (My guess, but I am sure) large format/plate camera lens, must be from around 1910s time...

Chekc this auction, same aperture mechanism,

Click here to see on Ebay

I have used these lenses (some from that time, but mostly large format) with bellows and extension tube (small bellows doesnt help in reaching to infinity).

But, how do you control focussing, or this is fixed focus.

luisalegria · Expire: 2018-01-18

When I got it it came attached to an Accura focusing extension tube in Exakta mount, which took care of focusing. Later I mounted it on my Exakta bellows. It was threaded M40, the same as the Exakta accessory thread - Exakta extension tubes, microscope mounts, etc. actually use this thread, so its easy to attach a mount.

I converted my Exakta bellows to work on my Pentax.

I think this may be another case of an ex-military optic converted to civilian use.