Al Kaplan
Veteran
Astro Berlin made some lenses that would fit on the Visoflex II & III with their adapter. The 150/2.3 Astro Pan Tachar, a 4 element air spaced design, was a real killer!
It's possible (and not difficult) to adapt some of those cheapy 400mm f/6.3 T-mount lenses from the 1960's to work on the Visoflex II and III with infinity focus. If anybody wants directions I'll write a few paragraphs.
Some of them scored better on Modern Photograpy Magazine's tests than the 400/6.8 Leitz Telyt.
http://thepriceofsilver.blogspot.com
It's possible (and not difficult) to adapt some of those cheapy 400mm f/6.3 T-mount lenses from the 1960's to work on the Visoflex II and III with infinity focus. If anybody wants directions I'll write a few paragraphs.
Some of them scored better on Modern Photograpy Magazine's tests than the 400/6.8 Leitz Telyt.
http://thepriceofsilver.blogspot.com
Last edited:
BillBingham2
Registered User
Al,
Please do. no active need now, but one never knows.
Thanks.
B2
Please do. no active need now, but one never knows.
Thanks.
B2
Al Kaplan
Veteran
Adapting a cheapy 400mm tele to Visoflex II/III mount.
Adapting a cheapy 400mm tele to Visoflex II/III mount.
First off you're going to need a LTM to M bayonet adapter. A Chinese cheapy is fine. It doesn't have to look nice. Most, if not all, all of these 400 f/6.3 lenses consist of a positive front lens and a negative rear group very close to the rear of the lens. The positive front group is less than 400mm in focal length. The negative rear group is really a "Tele-Extender" so you end up with a 400mm lens.
If we increase the lens to film distance the lens focuses closer. We can increase the lens to film distance and maintain infinity focus by moving the front group back, bringing it closer to the rear group. Immediately in front of the knurled grip to turn the lens to focus should be a place where the focusing grip is screwed into the front barrel, tube really, leading to the front group. The threaded area is fairly long so there's room to screw it deeper if you cut off some of the unneeded thread.
Take your LTM to M adapter, be brave, and using a half round file start filing most of the 39mm LTM thread from the inside of the adapter. With the flat side of the file remove almost all of the 41mm T thread from the base of the lens. You want to get it so you can force the T thread into the adapter with slight pressure and at this point still be able to remove it! Now apply some epoxy to the threads, put the adapter in your Visoflex and put the lens barrel in the adapter lining up the top side where it belongs, on top. Now remove the unit from the Visoflex to let the epoxy harden. Clean the flanges on the Visoflex and on the adapter with alcohol just to be safe. Let it harden overnight.
Now you have a lens that only focuses closer than infinity. Either get a fairly large sharpening stone or staple some coarse emory paper to a flat board. You're going to shorten the threaded section ahead of the focusing knurl by perhaps a couple of mm. Hold the lens section so that the surface to be ground down is flat against the stone or paper and start moving it. Every once in awhile assemble the lens and see how close you are. If you go a bit to far the lens will focus a bit past infinity but still work OK. If you're careful it'll be pefect!
Adapting a cheapy 400mm tele to Visoflex II/III mount.
First off you're going to need a LTM to M bayonet adapter. A Chinese cheapy is fine. It doesn't have to look nice. Most, if not all, all of these 400 f/6.3 lenses consist of a positive front lens and a negative rear group very close to the rear of the lens. The positive front group is less than 400mm in focal length. The negative rear group is really a "Tele-Extender" so you end up with a 400mm lens.
If we increase the lens to film distance the lens focuses closer. We can increase the lens to film distance and maintain infinity focus by moving the front group back, bringing it closer to the rear group. Immediately in front of the knurled grip to turn the lens to focus should be a place where the focusing grip is screwed into the front barrel, tube really, leading to the front group. The threaded area is fairly long so there's room to screw it deeper if you cut off some of the unneeded thread.
Take your LTM to M adapter, be brave, and using a half round file start filing most of the 39mm LTM thread from the inside of the adapter. With the flat side of the file remove almost all of the 41mm T thread from the base of the lens. You want to get it so you can force the T thread into the adapter with slight pressure and at this point still be able to remove it! Now apply some epoxy to the threads, put the adapter in your Visoflex and put the lens barrel in the adapter lining up the top side where it belongs, on top. Now remove the unit from the Visoflex to let the epoxy harden. Clean the flanges on the Visoflex and on the adapter with alcohol just to be safe. Let it harden overnight.
Now you have a lens that only focuses closer than infinity. Either get a fairly large sharpening stone or staple some coarse emory paper to a flat board. You're going to shorten the threaded section ahead of the focusing knurl by perhaps a couple of mm. Hold the lens section so that the surface to be ground down is flat against the stone or paper and start moving it. Every once in awhile assemble the lens and see how close you are. If you go a bit to far the lens will focus a bit past infinity but still work OK. If you're careful it'll be pefect!
burninfilm
Well-known
The little monsters.
Lookin good! My 90mm Summicron looks and handles very well on my Nikon F. That 135mm Elmarit is impressive, considering the optical damage. Of course, you do realize I soooo coulda snatched those lenses out from under ya if I wanted.
One of these days, I'll find a way to talk you out of that old beater 642XXXX Nikon F.