Archived posting to the Leica Users Group, 2001/02/27

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Subject: [Leica] Re: Focussing cine-camera lenses
From: Bernard Cousineau <flatbroke@sympatico.ca>
Date: Tue, 27 Feb 2001 22:33:06 -0500
References: <200102270010.QAA27616@mejac.palo-alto.ca.us> <003d01c0a0e9$e7210960$dd66989e@demon.co.uk>

Doug Richardson wrote:
> If any LUG members are involved in the cinema industry, could they
> tell me:
> If the lenses are manually focussed to preset distances, does that
> mean that the focussing is engraved to be read by someone standing in
> front of the lens, rather than by someone standing behind the camera -
> i.e the distance values are engraved 'upside-down' compared with those
> on a 35mm still camera lens?

I can't say for all cine lenses, but many of the ones that I have used
have their focussing index on the side of the lens, rather than on top.
Focussing is done by the focus puller standing in front of the camera
operator, to the side of the camera. A focusing wheel is connected to a
gear that rotates the focussing ring on the lens. Paper disks are put on
the wheel so that the focus puller can mark the focus points for a shot
with a permanent marker. These are often numbered sequentially and
correspond with tape marks on the ground or other visual references
outside of the frame. Older lenses are no designed for follow-focus
gears, but are often engraved so that the camera operator can see the
distance markings with his/her left eye while shooting. This is an art
which requires much practice, of course.
 
> Do cine lenses have depth-of-field markings similar to those on
> still-camera lenses?

No. Depth-of-field values are usually looked-up in a reference manual,
such as the "American Cinematographer Manual," published by the American
Society of Cinematographers (a.k.a. ASC, an acronym that you will no
doubt recognize from film credits).

I don't know about your lens, but I would hazard a guess that it was
meant to be used on a copy stand, with the camera facing down. Or that
it was assembled by Snah...

Bernard

In reply to: Message from "Doug Richardson" <doug@meditor.demon.co.uk> ([Leica] Re: Focussing cine-camera lenses)