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confusion with Arri standard mount


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#1 Edgar Nyari

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Posted 22 July 2015 - 03:41 PM

Hi there,

 

Recently I got a Schneider 28mm Xenon lens with the Arri standard mount, and a PL adapter for attaching it to my camera.

 

But I'm very confused about something,

 

I see Cooke Kinetal lenses have the same structure, so I'm sure someone will have the right answer, either from experience with Kinetal or Xenon lenses.

 

Here is the issue:

 

the lens has two rings, one for the aperture, and another for focus. The whole thing makes sense if you somehow attach it to the rear end (which is obviously not how this lens is attached). In that case turning the first ring changes the aperture while all other parts of the lens are fixed, and turning the second ring turns the cylinder body of the middle part of the lens, thus changing focus.

BUT

if you attach the lens where it's supposed to be attached: on the barrel with a little chanel where the screws fall into. Then you have a funny situation: the second ring can't be turned at all, because its connected to the middle cylinder and thus to the mount screws. Turning the aperture ring then changes the focus, and you can't change the aperture because you can't fix the inner part from rotating with it.

 

And I missing something here?

 

I know that the situation might be different when using the PL mount adapter, but I'm scratching my head thinking how on earth did they use these lenses even on cameras that have standard arri mounts, because no matter where you use it, it seems the screws have to be fixed to the middle rotating part.

 

thanks

 

Edgar


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#2 Jean-Louis Seguin

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Posted 22 July 2015 - 04:54 PM

These lenses were designed to fit the Arriflex camera lens mount where they are secured in place by two spring loaded levers. This would allow the lens barrel to rotate freely inside the camera mount cavity for focusing.

After-market adapters, which use setscrews to attach to the lens, block the free rotation of the lens barrel. You need to get a better designed adapter.

Edited by Jean-Louis Seguin, 22 July 2015 - 04:55 PM.

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#3 Gregg MacPherson

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Posted 23 July 2015 - 12:29 AM

Have a look at Les Bosher's website

http://www.lesbosher...k/lensadapt.htm

 

The mount adapter called " Arri PL - Arri Standard with Spring loaded levers (for Cooke type Lenses) " is probably the one that will work for you.  Its a camera port adapter (stays on the camera,  I assume from what I have learned of his other adapters.),   to which you could mount all your older Arri-S mount lenses,  the ones that need to rotate in the port to focus (use some vaseline) can do so.

 

But maybe call him first,  to confirm this technical issue.  This camera port adapter may not be cheap,  but you save by being able to mount all your old Schneider and Cooke Kinetals etc...

 

I have a Les Bosher Pl mount adapter for TS mount here (Eclair ACL) and the design and workmanship is ....excellent.  So the cost may be worth it.  Please pass on the complement to him if you chat.

 

There are other schneider,  maybe later versions,  not sure, which focus in the more normal modern way,  the lens can be fixed in the port,  the rotation to focus the lens is happening internally.

 

Old stuff,  lots to figuire out.

 

Cheers,

Gregg.


Edited by Gregg MacPherson, 23 July 2015 - 12:32 AM.

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#4 Edgar Nyari

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Posted 26 July 2015 - 07:48 AM

Hi there,

 

Thank you very much. I guess for now I'll have to deal with it as it is, but at some point I'll get the other type of adapter. I've contacted the manufacturer of the adapter I have right now and they confirmed that on these type of lenses it causes this sort of problem.

 

thanks

 

Edgar


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