Adapting a lens that has no focus?

[Yan Lauzon]

I acquired an "unknown" soviet lens off ebay, as a way to try new things. All I knew about it was its m42 mount. I didn't quite know what to expect until it recently got here. It has no markings.

The lens has a working iris and nothing to focus. Come to think of it, either it is incomplete or that's some sort of projection lens.

The barrel protrude beyond the lens and has threading on the outside, as to attach something else.

If I hold the lens a few cm away from the camera I can achieve focus. I ordered a focusing bellows as a quick way to use the lens (still waiting on it) but would like to know of other options to adapt this into a useable lens.

Any ideas greatly welcomed.

 

[dxqcanada]

I've never had a Russian lens ... nor an M42 ... but I will guess ...
Yes, looks incomplete ... I would guess the front focus cell is missing.
Possibly an outer barrel of some sort (that would turn to adjust focus) ?
With an M42 mount there should also be a pin sticking out the back to actuate the aperture ... yours has a slot, hmm.

 

[Yan Lauzon]

Thanks for the inputs.
I wonder if I can manage to find a replacement front focusing element.


The aperture is free, I can dial it and it remains open/closed. I wonder if that's by design or if it has been tempered with.

Regardless, it's an interesting project, for which I am digging to find more information.

 

[dxqcanada]

You are quite adventurous.

 

[john.margetts]

Russian M42 lenses were often not automatic - ie did not have that pin to close the aperture - my 1972 Helios 44 that came with my Zenit E did not have that pin.

I agree that the lens is incomplete and should have a further element (or two) that provide the focus.

 

[Yan Lauzon]

Thanks for confirming my impressions.

Do you think I could scavenge elements from other broken lens? There are numerous lens on ebay sold as-is, I may be looking for cheap donner lenses if the idea makes sense.

 

[Yan Lauzon]

I am looking at m42 focusing helicoid, thinking that may very well do the trick. Anyone ever tried that?

 

[SquarePeg]

I have a projector lens adapted for my Fuji mount. I bought it already adapted but I can tell you that the person who made it used some gears and a cylinder that expand and contract which is sort of a focusing mechanism. I do a lof of focusing by my feet. It has awesome bokeh though so I like using it.

I think I posted a photo of it on here. I’ll see if I can find it. Here’s a photo taken with the lens which is a Pentacon 80mm AV 2.8

 

[Derrel]

Camera Adjustable Focusing Helicoid Ring Adapter Macro Extension Tube M65 36-90 | eBay

I would do some searching on this search string.
Adjustable Focusing Helicoid Ring Adapter
Still, if the front cell is missing, this lens might still be a dud. try "free-lensing it, or "reverse-direction free-lensing", and see if you can get it to form an image on a d-slr or mirrorless camera. If not...I would write this lens off, and buy a lens with known functionality and a full component of lens parts/elements.

 

[Yan Lauzon]

Thanks @Derrel.
I already tried free-lensing it.

It seems I can manage to focus far away around 1.5-2cm from the camera, and focus rather close at 4-5 cm

Ideally I'd like something that can vary between 12mm and 60mm, but I don't think that's possible. Maybe stacking two up.


I didn't think about reverse-lensing it... Thanks for the idea. I just tried. I can focus at about 2 feet, or closer if I free-lens it.

 

[Derrel]

You might be able to rig something up with a body cap, and then a drill and small bit, and a file, some epoxy, and some PVC pipe pieces, etc..

 

[Yan Lauzon]

Some rack-and-pinion style focuser a la telescope would be nice too, but simple tight fitting may be interesting, thanks for the idea.

 

[Yan Lauzon]

I ordered m42 helicoïd from ebay and will start from there.

 

[petrochemist]

I've adapted quite a few projector lenses & collected more I have NEVER seen one with an aperture.
My initial thought was that it might be a enlarger lens even though most of these are M39 but looking at the pictures it doesn't look like one or a partial camera lens. The big screws are just plain wrong!
I suspect it's a process lens - it looks similar to the sort of thing my father had in a reprographic system years back.
It may fit into the largest helicoid I have M42 at the camera side & 52mm on the outside (as filter threads) length varies from 35-90mm. There is also a 65mm version available but I've not played with one of them yet.

Another option that can be helpful for initial experiments with unknown lenses is using a bellows - they cover a wider range of lengths.

 

[petrochemist]

You might be able to rig something up with a body cap, and then a drill and small bit, and a file, some epoxy, and some PVC pipe pieces, etc..

This body cap approach was ideal for mounting my 1930's Kodak astigmat onto my bellows. I didn't need the epoxy or pipes for that, but perhaps I should redo the adaption using a helicoid now they are so much more available.