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C mount adapter for Bolex


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#1 alexandros petin

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Posted 19 October 2007 - 01:43 PM

Hello
I bought a c mount adapter and now i can use my nikon lenses with my bolex (nikon brand adapter)
i read here cinematography that the lenses need to be collimated. My test roll shows no problems except with the 50mm when wide open 1.4 it is a bit soft but still acceptable(for me). If i dont collimate the lens is that a big problem?
Thank you
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#2 Sir Alvin Ekarma

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Posted 19 October 2007 - 02:18 PM

There might be problems focusing to infinity. I have some M42 lenses (85mm, 100mm) for my EBM and they need to be tweaked.
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#3 alexandros petin

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Posted 19 October 2007 - 03:24 PM

Well i will check again the negatives to see those infinity shots cause i never thought infinity would be a problem.About the m42 lenses i knew that problem but for still cameras.well not only.
On my next test i will measure precisely the distanse of the subject to compare it to the lenses distance marks. In my first i relied on the viewfinder only.
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#4 Nick Mulder

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Posted 20 October 2007 - 01:28 PM

Collimating wont solve the problem ... Its unfortunately its a myth - have a read here to understand why:

http://www.apecity.c...6mm_cameras.pdf

All is not lost however... as the info states try each lens out - your wide Nikons may still be ok closed down a little
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#5 Jonathan Bowerbank

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Posted 20 October 2007 - 03:46 PM

...My test roll shows no problems except with the 50mm when wide open 1.4 it is a bit soft but still acceptable(for me).


That's normal for a lot of lenses, they all function at their best when closed down at least one stop from their maximum aperture.
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#6 alexandros petin

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Posted 20 October 2007 - 04:08 PM

Comparing the frame with 35mm stills when wide open the 16mm frames seem to be a little better!
maybe because the frame is at the center of the lens so better result etc.
So that viewfinder prism again, Nick Mulder, right?
Well i quess we settle down with our cameras special charecteristic and as you people of the forum have numerous times suggested TEST TEST TEST.

thank you again for your help.
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#7 Nick Mulder

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Posted 21 October 2007 - 03:33 AM

Comparing the frame with 35mm stills when wide open the 16mm frames seem to be a little better!
maybe because the frame is at the center of the lens so better result etc.
So that viewfinder prism again, Nick Mulder, right?
Well i quess we settle down with our cameras special charecteristic and as you people of the forum have numerous times suggested TEST TEST TEST.

thank you again for your help.


A lens will look 'better' in 35mm if all other factors are kept the same simply because the ground glass is bigger and the same detail isn't as magnified as in 16mm ...

A lens that covers 35mm will probably have no problem with edge fuzziness working in 16 or super16, certainly not vignetting so you could easily get away with not having done the re-centre...

Yip, you got it - test, and good luck with the wides - hopefully your lenses will be winners
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