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My Switar c mount won't fit?


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#1 Brian Rose

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Posted 27 January 2007 - 03:01 PM

I just got a 25mm Switar C-mount for my Bolex, yet when I went to mount it, I found that the rear was too large. There is this extra ring in the rear of the lens that prevents it from screwing in fully. It is an AR lens, but I had assumed that all the c-mount switars were standard, aside from the rx, non rx distinction. What happened?
Brian R.
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#2 Dennis Kisilyov

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Posted 27 January 2007 - 03:03 PM

I just got a 25mm Switar C-mount for my Bolex, yet when I went to mount it, I found that the rear was too large. There is this extra ring in the rear of the lens that prevents it from screwing in fully. It is an AR lens, but I had assumed that all the c-mount switars were standard, aside from the rx, non rx distinction. What happened?
Brian R.



Could you please be more specific as to the type of Bolex this is? H-16?
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#3 Brian Rose

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Posted 27 January 2007 - 03:11 PM

Sorry, forgot to mention. It is an H-16 Reflex.
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#4 Mike Rizos

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Posted 27 January 2007 - 09:51 PM

I just got a 25mm Switar C-mount for my Bolex, yet when I went to mount it, I found that the rear was too large. There is this extra ring in the rear of the lens that prevents it from screwing in fully. It is an AR lens, but I had assumed that all the c-mount switars were standard, aside from the rx, non rx distinction. What happened?
Brian R.

Be careful you don't damage the prism!!! The early AR Switars had a deeper thread and can NOT be used on a reflex.
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#5 adam berk

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Posted 28 January 2007 - 11:08 PM

Funny, I just ran into the EXACT same problem. I was all pumped to get myself a mint f1.4 25mm switar for only $35 for my EBM, yet found it has that deep thread once it arrived.
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#6 Scott Bullock

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Posted 28 January 2007 - 11:36 PM

Be careful you don't damage the prism!!! The early AR Switars had a deeper thread and can NOT be used on a reflex.


I believe the AR style lenses can be used on a reflex Bolex as long as the lens is properly shimmed. For definitive answers to those raised in this thread, contact Dieter Schaefer at ProCam. He's a factory authorized Bolex dealer and service technician.

Ph. # 928-708-9901
Email: bolexusa@yahoo.com
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#7 Clive Tobin

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Posted 29 January 2007 - 11:40 PM

I believe the AR style lenses can be used on a reflex Bolex as long as the lens is properly shimmed. ...

How many times do we have to slay this old wive's tale before it stays dead? C and RX lenses focus to the exact same film plane distance in air. And the F stop calibrations are the same. The difference is in the optical formula in the RX mount to allow for the dispersion etc. of the glass prism.
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#8 Scott Bullock

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Posted 30 January 2007 - 01:46 PM

How many times do we have to slay this old wive's tale before it stays dead? C and RX lenses focus to the exact same film plane distance in air. And the F stop calibrations are the same. The difference is in the optical formula in the RX mount to allow for the dispersion etc. of the glass prism.


This is not what I've been told by authorized Bolex technicians nor is it what I've discovered in my own usage of reflex Bolex cameras. A non-RX, 'C' mount lens needs to be re-collimated for use on a reflex Bolex; the flange depths of a regular 'C' mount lens and an RX 'C' mount lens are not the same.
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#9 John Holland

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Posted 30 January 2007 - 01:53 PM

Hi what you have been told is correct ,dont f-up the prism . John Holland.
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#10 Leo Anthony Vale

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Posted 30 January 2007 - 02:38 PM

the flange depths of a regular 'C' mount lens and an RX 'C' mount lens are not the same.


The refractive index of the prism is not the same as. That is why placing a filter behind a lens shifts the focal plane away from the lens.

So while the physical flange depth of te C and Rx mounts are different. The effective optical depth of the is the same, else Pan Cinors would not be interchangable between the two.
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