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class="Paragraph" Focus Terms

Published : 4th April 2004


I've been interested in the origins of the term "rack focus", guessing that it derived from the gears used in a follow-focus system. Probably first used as a noun, later becoming an action. I decided to look up the word "rack", and one of the definitions is : "A cause of intense anguish" -- how appropriate!

Can anyone confirm the above origin of the term? And where did "pull focus, or focus pull" come from?

Chris Mosio
Cinematographer/Seattle



>"A cause of intense anguish" -- how appropriate!"

I heard a rumour that the early Bausch and Lomb anamorphic lenses had two focus knobs on them, requiring two focus pullers. If a shot was buzzed each assistant always had someone to point at.

Lots of intense anguish there, I'm sure.

Art Adams, DP
Mountain View, California - "Silicon Valley"
http://www.artadams.net/



>I heard a rumour that the early Bausch and Lomb anamorphic lenses >had two focus knobs on them, requiring two focus pullers. If a shot was >buzzed each assistant always had someone to point at.

Nothing to do with anguish. Old Mitchell’s, B&H's, Auricons and the like had a side viewfinder: one could only "see" focus and composition if the lend was 'racked over'. It was moved over with a big knob and it rode on a notched horizontal track. Hence: rack for focus or in short 'rack focus'.

Some camera's had a view tube that was 'racked over' to look through the negative that thereby acted like a ground glass. That was before the black backing coat of course.

Robert Rouveroy csc
The Hague, Holland

I plan to live forever. So far, so good.



"Rack focus" does indeed derive from the gears used, as in rack and pinion.

The pinion is usually a smaller gear and the rack is usually a straight assembly or rack of teeth as in a view camera and some early MP cameras-- not to be confused with medieval torture device of the same name, although as has already been pointed out, there are similarities in effect for the focus puller.

"Pulling focus" is self-evident. When the term came into use can only be answered by someone a lot older than I am.

BTW, where's Jeff Kreines?

Brian Heller



>"Pulling focus" is self-evident. When the term came into use can only be >answered by someone a lot older than I am. BTW, where's Jeff Kreines?

Billy Mitchell ("Intolerance" etc) used lenses where the barrel was 'pushed' and 'pulled' to affect focus. As he eminently was not able to pull at the lens and crank the camera simultaneously, he was (probably) the first cameraman to yell "pull focus" to his assistant.

As is explained in one of the links at :

http://www.xs4all.nl/~wichm/filmsize.html

If you can't find your info there, it most probably does not exist :

Robert Rouveroy csc
The Hague, Holland

I plan to live forever. So far, so good.



Robert Rouveroy writes:

>Nothing to do with anguish. Old Mitchell’s, B&H's, Auricons and the like >had a side viewfinder: one could only "see" focus and composition if the >lend was 'racked over'.

Not to quibble with so eminent a film historian, but I believe the term "rack focus" pre-dates rack-over cameras, but I may be wrong. However "The Rack", the medieval torture instrument, and gear rack derive from the same source.

"The Rack" used a rack and pinion system for mechanical advantage.

Brian "ouch" Heller
I 600 DP