Lens mount mystery: Tele-Lentar 1:5.5 f=300mm

Of all the lenses I have picked up at thrift stores, I have been able to identify every mount save one: This Tele-Lentar 300mm prime telephoto lens. So, I am appealing to the Intartubes for help. The lens has some sort of swappable intermediate mount, so I really have 2 chances of figuring out an adapter solution – either figuring out what the base flange-and-groove mount that the lens has, or figuring out what mount the flange attachment converts to.

The base flange mount doesn’t correspond to any mount system I’ve heard of – it’s not a T/T2 mount and I’m pretty sure it’s not an early Tokina M47 mount (although I’ve read that the Tele-Lentar lenses were made by Tokina). Beyond that I have no clue.

The flange attachment converts to what looks like a fairly common 3-blade bayonet that looks a lot like a Nikon F or Pentax K mount, but isn’t either one – I’ve tried both converters, and they don’t even remotely work. Oddly, a Pentax K end cap fits nicely on it, but that probably just indicates that the diameter of the bayonet blades are similar.

Here’s some pics – please help if you can (:

The Tele-Lentar 300mm has, what looks like *15* aperture blades, the bokeh should be really amazing...

The Tele-Lentar 300mm has, what looks like *15* aperture blades, the bokeh should be really amazing…

This photo shows both the base flange & groove mount and the attachment with the unknown bayonet mount.

This photo shows both the base flange & groove mount and the attachment with the unknown bayonet mount.

The inside of the attachment, held onto the base mount by 3 screws, two of which are missing. If I have to use this intermediary adapter (if I find out only the bayonet mount type) I'll need to find more screws. Ideally, I want to find the base flange mount to M42 adapter, and skip using this mystery adapter altogether.

The inside of the attachment, held onto the base mount by 3 screws, two of which are missing. If I have to use this intermediary adapter (if I find out only the bayonet mount type) I’ll need to find more screws. Ideally, I want to find the base flange mount to M42 adapter, and skip using this mystery adapter altogether.

In the Manual Focus Forums, I found a helpful *text* guide that fairly clearly describes various lens mounts:

Exakta: 3 identical sized lugs w/o cuts in them. rather small mount, lug/screw on “flat”, auto lenses have “arm” with shutter release.
Konica: 3 lugs with cut in center of widest lug. No levers.
Minolta: 3 lugs, cut on right side of one lug that is opposite the one lever.  (rod?)
Nikon: 3 lugs, aperutre lever just inside one lug. Cut/detent on opposite side of lens from that lug. famous “ears” on all older lenses, this is good for 90% of Nikon ID.
Olympus: 3 lugs, lever just inside one lug with 2 release buttons on opposite side of the lens.
P/K: 3 lugs, long leveer just inside one lug and detent by that lug.
Y/C: 3 lugs, 2 levers, smallest lever by lug with cut in it. Often an adjustable tab on rear.

Updated: April 11, 2024 — 12:37 pm

14 Comments

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  1. That is kind of a strange mount. I was thinking along the lines of Yashica or Miranda since any other strange mount I can think of would be from a camera too expensive to be found in a thrift store. I doubt those would have a third party lens too. I know there are some out there I never saw nor heard of.

    1. Yeah, it’s a weird one. I’m pretty sure the Bayonet isn’t a Miranda or Yashica/Contax, The closest I can see is Konica, But it’s not quite an exact match.

  2. wow I have no idea. I hope someone comes through for you.

  3. Ted, I wouldn’t say this was keeping me awake at night, but just looking at the set-up, I reckon you might be able to ditch the base flange bayonet ring thing completely. It looks like a generic, non-coupled 3rd party lens. I had a slide copying attachment which cme ‘naked’ and had to be fitted with a camera-specific adapter fixed with three little grub screws. Memory tells me it was aT2 adapter but Google proves me wrong. I had two, one for M42 and one for Nikon AI. No mating thread for the lens, just those grub screws (so you can orientate the barrel to get focus intex at 12 oclock, regardless of the lens/camera combination. Not sure if I still have either, but I’ll check and let you know if I do.

    1. That would be awesome! :D

      even if I know the proper name for the mount, I could probably scrounge one up. I’d definitely like to ditch the current mystery adapter and put an M42 mount on it. Then I could use it with my teledaptors along with my other M42 lenses. For reference, the lip of the lens coupling is about 47mm measuring the outer rim. That’s what made me think it might be an M47, but M47 seems to be a screw-mount. I have tried a T/T2 adapter, but obviously the tube of the lens is too fat to fit in the 42mm inner ring and too skinny to fit in the outer ring (with the inner one removed – i tried that too.) Let me at least know if you find out what the adapter is called – I’d love to be able to use this one instead of staring at it in frustration anytime I need something between 200mm and 500mm. :P

  4. Hi,
    That is a T mount. The flange that you see (on the lens) is the remnant of the inner ring of a t mount adapter. Sometimes these get siezed onto tthe t mount threads of the lens and (almost impossible to remove without damaging lens). You simply need to buy a t mount adapter for the mount you need. Loosen the three adjustment screws on it, remove the inner flange, then mount it to the flange on the lens. Some lens manufacturers (early on) even produced the lenses with this flange at the end already (permanently attached).

    By the way the mount that you have in the photo looks like a Minolta mount. Or an older Mamiya. Nothing really exotic.

    1. I thought so too, and picked up a couple of T/T2 to M42 mounts to try out. Turns out that it’s not either. It’s a bit larger than a T adapter and a bit smaller than a T2. I’ll have to dig my Minolta out and try the original mount ring on it – I didn’t have a Minolta back when I wrote this, so never tried it. If it matches, I suppose I could re-mount the original ring and use the lens on the Minolta. It’d be nice to be able to use it for *something* :D

    2. oh, wait. I see what you’re saying re: the flanged bit. I never tried to unscrew that. I’ll give that a shot. :D

    3. Ok, you’re right on the money. That sucker was screwed on so tight I had to use a plumber’s pipe wrench to get it off, but off it came to reveal (printed on the underside of the reminant ring) “T2-Mamiya”.

      Thanks for the advice, now I can finally use the thing, more than a year after making this post. (:

      1. I came across your website while trying to find out how much I could sell my tele-lentar1:5.5 f=300mm any idea of how much and where to sell it

        1. ahh, it always pains me to be reminded that there are people stupid enough to imagine that bloggers have either the expertise or the interest in providing free appraisals for their sight-unseen and completely undescribed shit they want to sell on Ebay. Rather than spam-canning your question outright as it deserves, however, I will answer the only answer that is logical given what you’ve told me:

          Put it on ebay with a $5 minimum bid. Geez.

  5. Save some people some time if they come here like me, its a minolta-md mount.

  6. I have purchased a second hand Lentar 500mm mirror lens f:8 { with two internal filters for 11 and 16 }.

    It came with a male T mount as factory and I purchased an adapter that changed it to my M42 female.

    So, I think you may find the factory mount is a T. Regards, Roger DESHON, Toowoomba, Qld

  7. In the 2nd picture the mount with the center hole in center of one of the three flanges, that is a Konica camera mount. Theother mount that is most like that mount but hole is closer to the edge of the flange is a Minolta mount. Two are the same ust hole in iffrent spot. https://youtu.be/mBsjGVXV2m8

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