Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Funky mount on Primotar
Post new topic   Reply to topic
Home   Manual Focus Lenses
View previous topic :: View next topic  


PostPosted: Thu Jan 28, 2016 7:39 pm    Post subject: Funky mount on Primotar Reply with quote
Just received a 3.5/180 Primotar with a mount I don't recognize. The original box said Exakta on the bottom, but this is different from the Exakta mount I'm familiar with. I'm sure someone here will recognize it.




PostPosted: Thu Jan 28, 2016 8:02 pm    Post subject: Reply with quote
I guess this is the exakta external bayonet - mainly large lenses like this were using it.


PostPosted: Thu Jan 28, 2016 8:03 pm    Post subject: Reply with quote
Isn't that exacta external (outer) bayonet?


PostPosted: Thu Jan 28, 2016 8:17 pm    Post subject: Reply with quote
Hot sure if you can find appropriate adapter - i have never seen such.
I have a bellows with such flange

On what camera you will be using it ?


PostPosted: Thu Jan 28, 2016 9:09 pm    Post subject: Reply with quote
Yes certainly Exakta external mount.
Its common on the 180 Primotar.
I have one on a 300/4.5 Telemegor


PostPosted: Thu Jan 28, 2016 9:16 pm    Post subject: Reply with quote
Adaptation is a problem.
There are no commercial Exakta external mount adapters to anything that I know of.
I did adapt this mount to PK.
My fix for it was to create an overlay made from an M42->PK flanged adapter, with countersunk holes for the screws you have on the lens mount. I milled out slots/cavities for the Exakta flanges so the adapter would fit flush.
This added 1+ mm to the back focus but it wasn't that big a problem for the 300mm as it would go beyond infinity anyway.
On a 180 there is less scope for this sort of adaptation.


PostPosted: Thu Jan 28, 2016 10:24 pm    Post subject: Reply with quote
Is this is different from Exacta 66 breech lock? That is a 74.1 register. Any idea what the register is for this, if different? I can probably come up with something sine I now have a metal lathe.


PostPosted: Fri Jan 29, 2016 1:09 am    Post subject: Reply with quote
No, it looks just like what the Exakta 35mm external mount should look like. If you want to verify its just a matter of holding the lens up to your digital and checking how far out you can focus. Best tested with a mirrorless.
If tested with an SLR you can at least tell if you can get infinity with the camera a short distance from the lens. If you can't get infinity at all, even when pressed up close, its the 35mm mount.


PostPosted: Fri Jan 29, 2016 1:11 am    Post subject: Reply with quote
Also, measure the outer diameter of the barrel section that projects into the camera side of the lens mount. If its 38mm or a bit less, ditto.


PostPosted: Fri Jan 29, 2016 1:39 am    Post subject: Reply with quote
Interesting I didn't see it before, may only made for western export ?!


PostPosted: Fri Jan 29, 2016 1:42 am    Post subject: Reply with quote
If you have a lathe you could maybe neatly turn down a flanged M42->something else adapter, drill countersunk holes to match the screws there (could be iffy with large bayonets as the screws will overlap with the bayonet).
You could maybe get that to fit where the mount plate is now.

The register is regular Exakta, 44.5 or so, measured from the "flat" where the lug is.


PostPosted: Fri Jan 29, 2016 4:24 am    Post subject: Reply with quote
luisalegria wrote:


The register is regular Exakta, 44.5 or so, measured from the "flat" where the lug is.


Thanks, Luis. If the register is the same, then wouldn't it work if I lathed off the raised areas (bayonet) on the lens and the same to an Exakta adapter and then mate the two flat surfaces?


PostPosted: Fri Jan 29, 2016 4:31 am    Post subject: Reply with quote
You can just remove the mount IIRC, by unscrewing those screws. It should be a mount plate. Just make a new mount plate.
That would be a reversible mod.
If you place a plate on top of the existing plate after removing the lugs you will still be adding the thickness of the new plate.
That's what I did pretty much, but I cut cavities under the new mount for the old lugs to go into, I wanted to keep it a reversible adaptation.


PostPosted: Fri Jan 29, 2016 7:22 am    Post subject: Reply with quote
woodrim: i guess you can salvage the mount from a broken exakta camera and then put it on your adapter.
I have one spare if you need it.


PostPosted: Fri Jan 29, 2016 9:12 am    Post subject: Meyer interchangeable mount cone? Reply with quote
Did you try to twist&unscrew a securing ring that might sit immediately above the conical mount piece?

I learnt that my Meyer 135 had a removeable mount so that it would be posible to fit it to M42 as well as to Exacta. Perhaps your lens has a similar feature. Those mount rings however might be difficult to find since the market is probably cornered by collectors of original DDR stuff, but threads are easier to have made than bayonet flanges.

p.


PostPosted: Fri Jan 29, 2016 3:56 pm    Post subject: Reply with quote
Attila wrote:
Interesting I didn't see it before, may only made for western export ?!

Really? I would have thought you've seen it all. I purchased it from Poland, so probably not an export to west.


std wrote:
woodrim: i guess you can salvage the mount from a broken exakta camera and then put it on your adapter.
I have one spare if you need it.

Thank you Stefan, but I believe I need the mount from a lens, not camera. It seems I can get a cheap 2x converter on ebay and steal the mount from it if that is the direction I go.

paulhofseth wrote:
Did you try to twist&unscrew a securing ring that might sit immediately above the conical mount piece?
I learnt that my Meyer 135 had a removeable mount so that it would be posible to fit it to M42 as well as to Exacta. Perhaps your lens has a similar feature. Those mount rings however might be difficult to find since the market is probably cornered by collectors of original DDR stuff, but threads are easier to have made than bayonet flanges.
p.

Yes, the Meyer 135mm does, but not so sure about this one. If so, it looks like it will remove from under the tripod ring if at all.

luisalegria wrote:
You can just remove the mount IIRC, by unscrewing those screws. It should be a mount plate. Just make a new mount plate.
That would be a reversible mod.
If you place a plate on top of the existing plate after removing the lugs you will still be adding the thickness of the new plate.
That's what I did pretty much, but I cut cavities under the new mount for the old lugs to go into, I wanted to keep it a reversible adaptation.

What I had in mind was to remove anything that interfered with the two mating surfaces, then permanently attaching the two. I will have to examine them more closely today if I get the time. I suppose I can also machine a new mount from some of my scrap aluminum. I work with aluminum every day and now have machining capability with the lathe. Looking for a milling machine next. As for being able to return the mount to original, bah. I bought the lens for me, not the next guy, and it was only $32. Besides, Who is going to want that funky mount?


PostPosted: Fri Jan 29, 2016 9:39 pm    Post subject: Reply with quote
I don't think you need to do much machining really.
Unscrew old mount plate.
Get an M42 non-optical flanged adapter for some mount with smallish back focus, Pentax K may be best.
Turn down flange so that it fits where the old mount plate went.
Drill countersunk holes for where the screws should go.
Screw in place.


PostPosted: Sat Jan 30, 2016 12:05 am    Post subject: Reply with quote
woodrim wrote:
Attila wrote:
Interesting I didn't see it before, may only made for western export ?!

Really? I would have thought you've seen it all. I purchased it from Poland, so probably not an export to west.
Or maybe collected in Germany at western part at garage sale or similar, who knows.


std wrote:
woodrim: i guess you can salvage the mount from a broken exakta camera and then put it on your adapter.
I have one spare if you need it.

Thank you Stefan, but I believe I need the mount from a lens, not camera. It seems I can get a cheap 2x converter on ebay and steal the mount from it if that is the direction I go.

paulhofseth wrote:
Did you try to twist&unscrew a securing ring that might sit immediately above the conical mount piece?
I learnt that my Meyer 135 had a removeable mount so that it would be posible to fit it to M42 as well as to Exacta. Perhaps your lens has a similar feature. Those mount rings however might be difficult to find since the market is probably cornered by collectors of original DDR stuff, but threads are easier to have made than bayonet flanges.
p.

Yes, the Meyer 135mm does, but not so sure about this one. If so, it looks like it will remove from under the tripod ring if at all.

luisalegria wrote:
You can just remove the mount IIRC, by unscrewing those screws. It should be a mount plate. Just make a new mount plate.
That would be a reversible mod.
If you place a plate on top of the existing plate after removing the lugs you will still be adding the thickness of the new plate.
That's what I did pretty much, but I cut cavities under the new mount for the old lugs to go into, I wanted to keep it a reversible adaptation.

What I had in mind was to remove anything that interfered with the two mating surfaces, then permanently attaching the two. I will have to examine them more closely today if I get the time. I suppose I can also machine a new mount from some of my scrap aluminum. I work with aluminum every day and now have machining capability with the lathe. Looking for a milling machine next. As for being able to return the mount to original, bah. I bought the lens for me, not the next guy, and it was only $32. Besides, Who is going to want that funky mount?
Post new topic   Reply to topic
Home   Manual Focus Lenses
Page 1 of 1