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Nikon to C-Mount adapter on Bolex Reflex


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#1 Bryce Lansing

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Posted 29 August 2009 - 02:47 AM

I just bought a Bolex Reflex H16 on ebay, and I'm excited to start shooting with it! I've been pleasantly surprised to see Bolex shot footage (telecined to HD), that was at least as sharp as the footage I get on my HVX200, but of course looking like good old film.

The Reflex I got didn't come with a lens. I've been reading a lot about the issue with the prism on Reflexes, and how RX lenses were made to compensate for the issue. I have a good set of Nikon Primes that i'd love to use on it with a c-mount to Nikon adapter, but I'm afraid the prism might effect it.

If it were cheap, I'd test it myself, but after calculating film/processing/telecine costs, I'd rather ask around and see if using Nikon lenses is worth it before I try it. Has anyone had an luck?
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#2 Bernie O'Doherty

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Posted 29 August 2009 - 01:20 PM

What a simple yet complex issue this is. "c" mount ffd is 17.52mm. Because of the Bolex prism pulling the light angle further back into the camera, the ffd becomes 20.76mm. Also, the angle of focus is lessened with non-Rex lenses. So the edges may become slightly soft on wide non-Bolex lenses.
However, because of the increased diameter/field of focus of 35mm lenses, there is no worry about softness on the edges. There would be a mechanical adjustment required on the c to Nikon adaptor to bring it from 17.52mm to 20.76mm, an increase of 3.24mm. Hope all this doesn't further confuse the hell out of you.
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#3 Bryce Lansing

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Posted 29 August 2009 - 03:08 PM

What a simple yet complex issue this is. "c" mount ffd is 17.52mm. Because of the Bolex prism pulling the light angle further back into the camera, the ffd becomes 20.76mm. Also, the angle of focus is lessened with non-Rex lenses. So the edges may become slightly soft on wide non-Bolex lenses.
However, because of the increased diameter/field of focus of 35mm lenses, there is no worry about softness on the edges. There would be a mechanical adjustment required on the c to Nikon adaptor to bring it from 17.52mm to 20.76mm, an increase of 3.24mm. Hope all this doesn't further confuse the hell out of you.


It is kind of confusing, but I think I understand.
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#4 Glenn Brady

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Posted 01 September 2009 - 02:24 PM

There would be a mechanical adjustment required on the c to Nikon adaptor to bring it from 17.52mm to 20.76mm, an increase of 3.24mm.


This would be necessary only if one intends to scale focus, wouldn't it? Most of my Nikon F-mount lenses work fine on my Bolex H8 RX4 cameras with their 15.305mm ffd using the Nikon F-C adapter. As I recall, those I've tried focus beyond infinity.
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#5 Glenn Brady

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Posted 01 September 2009 - 02:25 PM

double post

Edited by Glenn Brady, 01 September 2009 - 02:28 PM.

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#6 Bernie O'Doherty

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Posted 01 September 2009 - 06:34 PM

That's right Glenn, I'm scaling focus as best as I can. I find that most, if not all, of the Nikon to "c" adaptors are off spec. Then again, a lot of Bolexes seem to need ffd zeroing. Finding exactitude here could drive you to drink !
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