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

Basic Info on Contax Mounts
Post new topic   Reply to topic
Home   Manual Focus Lenses
View previous topic :: View next topic  


PostPosted: Sun Mar 10, 2019 2:07 pm    Post subject: Reply with quote
justtorchit wrote:

......Can you mount lenses with helicoids OVER that mount, while also having the ability to mount the lenses INTO it, which require use of the helicoid?


Short answer is Yes. The two mount adapters in the first pic of my previous post both allow you to mount the the normal lenses (eg. 50mm f/2, 50mm f/1.5, 50mm f/1.4 etc.) that do not have built in focus helicals. Only the chrome adapter, which was salvaged from a Kiev camera, allows mounting of the normal lenses AND has three lobed external bayonet lugs for mounting of lenses, like your 13.5cm Nikkor, which do have a focus helical - see the pic below.

I hope this helps.

Paul



PostPosted: Sun Mar 10, 2019 4:22 pm    Post subject: Reply with quote
fiftyonepointsix wrote:
David: The "S-Mount" accommodates both Internal Mount 5cm (51.6mm) lenses and external mount lenses. The internal mount lenses rely on the camera's mount for focus. External mount lenses have there own helical, the mechanism translates the focus to the rotation of the camera's helical. The main difference between Contax and Nikon is the amount of rotation used to translate the focus from lens to camera. However- there are tolerances in the mechanical aspects of the mounts that might lead to filing down mounting prongs "here and there" between Contax, Nikon, and Kiev.


Thank you for that! Yeah the S-mount has been quite confusing to work out without explicit explanation, haha. I appreciate it! Also, it seemed to strange to think that those engravings and maybe even some levers on that mount would be covered by an 'external mount' lens. How unique!


PostPosted: Sun Mar 10, 2019 5:09 pm    Post subject: Reply with quote
[quote="justtorchit"Also, it seemed to strange to think that those engravings and maybe even some levers on that mount would be covered by an 'external mount' lens. How unique![/quote]

I agree it is confusing. Steve Gandy (Camera Quest) describes it this way:

"Rather than following Leica with a screw mount interchangeable lens system, Zeiss used a curious double bayonet system. The helical for the 50's was built INTO the camera body. The 50's used the INSIDE bayonet mount. The photo shows the latch locking down the 50/3.5. Wide angles and longer than 50mm lenses use the three prong OUTSIDE bayonet mount with their own built in helical focusing system. One of the outside bayonet prongs is shown just below the "Contax" nameplate. As bayonet mounts go, this one is rather time consuming. You have to set the camera body helical to infinity, matching the lenses, before mounting wides or Teles. Any real advantage the Contax bayonet has over the Leica screw mount method is rather dubious in my opinion."

I tried to think of a few reasons for Zeiss Ikon to design the camera this way. All I could come up with was that perhaps it reduced the size and/or cost of the camera with just a normal lens attached, or maybe it was there for greater support of heavier, longer lenses, or it simplified the creation of focus scales. Not sure why. In any event, it seems to have been touted as an advantageous feature.

It is not altogether unique. The MF Pentax 6X7 has this kind of a dual mount, with the external bayonet used to support the extra weight of long lenses, and the classic Miranda 35mm SLR mount has both an internal screw mount and an external bayonet mounts. Most confusing of all, I think had to be the classic Bronica S2 mount. This mount can focus lenses with focal lengths from 40mm to 200mm; longer lenses have their own helicoids (either separate or integrated) and can be mounted to the bayonet. The bellows accessory also uses the bayonet to mount onto the body. I am sure there are others as well!

Enjoy,

Paul


PostPosted: Sun Mar 10, 2019 6:01 pm    Post subject: Reply with quote
pdccameras wrote:
I tried to think of a few reasons for Zeiss Ikon to design the camera this way.


They tried hard to ruin their camera business and finally it worked. Wink


PostPosted: Sun Mar 10, 2019 6:40 pm    Post subject: Reply with quote
Exakta cameras had dual bayonet system for heavy lenses as well. While the Canon EX series has the camera associated helical system with screw mount interchangeable lenses.


PostPosted: Sun Mar 10, 2019 9:17 pm    Post subject: Reply with quote
tb_a wrote:
pdccameras wrote:
I tried to think of a few reasons for Zeiss Ikon to design the camera this way.


They tried hard to ruin their camera business and finally it worked. Wink


Good one! LOL


PostPosted: Sun Mar 10, 2019 9:45 pm    Post subject: Reply with quote
jamaeolus wrote:
Exakta cameras had dual bayonet system for heavy lenses as well. While the Canon EX series has the camera associated helical system with screw mount interchangeable lenses.


I forgot all about Exakta! A short time ago I picked up a nice 400mm f/5.5 Telemegor with such an external Exakta mount. I had a devil of a time finding a way to mount it to my Sony A7. All the easily available Exakta ->E-mount adapters are internal only. Finally, I realized that the early Exacta->Miranda adapters acoomodate both Exakta internal and external. From there it was Miranda->LTM and then LTM->Sony.

P.


PostPosted: Mon Mar 11, 2019 6:52 am    Post subject: Reply with quote
tb_a wrote:
pdccameras wrote:
I tried to think of a few reasons for Zeiss Ikon to design the camera this way.


They tried hard to ruin their camera business and finally it worked. Wink


Actually the mount system is nice to use for its age and makes the camera with for example J8 much smaller and better balanced if you compare to m39 system.



[img]Kiev 2 with Jupiter-8 lens by Sandor Somkuti, on Flickr[/img]


PostPosted: Mon Mar 11, 2019 11:24 am    Post subject: Reply with quote
kansalliskala wrote:
Actually the mount system is nice to use for its age and makes the camera with for example J8 much smaller and better balanced if you compare to m39 system.


Nonetheless only the LTM/M system survived.

BTW, my comment was a general observation because Zeiss Ikon/Voigtlaender had too many different proprietary systems until they gave up in the early 1970's.


PostPosted: Mon Mar 11, 2019 11:50 am    Post subject: Reply with quote
tb_a wrote:

BTW, my comment was a general observation because Zeiss Ikon/Voigtlaender had too many different proprietary systems until they gave up in the early 1970's.


I agree with Thomas. Zeiss Ikon (the camera design and manufacturing arm of the Zeiss conglomerate) was responsible for a number of engineering marvels over the years, but sometimes their marketing and overall business strategy didn't live up to their technical prowess. The Zeiss Compendium by Berringer and Small [url] https://www.amazon.com/Zeiss-Compendium-East-West-1940-1972/dp/1874707243/ref=sr_1_fkmrnull_1?keywords=zeiss+compendium&qid=1552304808&s=gateway&sr=8-1-fkmrnull [/url] provides an interesting viewpoint on the story.

paul


PostPosted: Mon Mar 11, 2019 1:42 pm    Post subject: Reply with quote
tb_a wrote:
kansalliskala wrote:
Actually the mount system is nice to use for its age and makes the camera with for example J8 much smaller and better balanced if you compare to m39 system.


Nonetheless only the LTM/M system survived.

BTW, my comment was a general observation because Zeiss Ikon/Voigtlaender had too many different proprietary systems until they gave up in the early 1970's.


Yes, the last and the most magnificient being Contax N.
(edit: I' not sure how much that had Zeiss camera design any more?)


PostPosted: Mon Mar 11, 2019 7:49 pm    Post subject: Reply with quote
Zeiss had to come up with alternative methods for the lens mount and for the RF coupling- due to Leica patents. The same with Leica not bringing out a combined vf/rf until after the war, Zeiss patents. The "Leica IV" was never brought past Prototype, had a combined VF/RF- and looked much like a Fed 2.


PostPosted: Mon Mar 11, 2019 8:08 pm    Post subject: Reply with quote
pdccameras wrote:
HI Keo,

There's been some great info shared in this post. Here is what I hope is a little more.


Thanks for the succinct and detailed explanations. That's really helpful.

Now I understand why I found the topic confusing in the first place! Laughing

Adapting Contax rangefinder lenses seems like something I will investigate further with all the great old glass available.
Post new topic   Reply to topic
Home   Manual Focus Lenses
Goto page Previous  1, 2
Page 2 of 2