Re: [Leica] focusing Minox

[Bernard Cousineau <flatbroke@sympatico.ca>]

Martin Howard wrote:
> >Focus is measured using tape whenever possible. Film
> > lenses are (or should be) calibrated for focus every time they go out on
> > a shoot. The focus puller marks each focussing point in a scene and
> > makes the transitions as the camera is running. The marks on the floor
> > are meant to guide the actors, and to help the puller determine how far
> > off they are from the measured distance.
> 
> Amazing.  How come they still stick to such, at least to the uninitiated, an
> antiquated and cumbersome technique?
Well, for a few reasons. 
First of all, you really wouldn't want to see the focus hunting back and
forth during a scene because it would be distracting, which means that
it is better to pre-mark it. If you are focussing by eye, you tend to go
past your best focus and then reverse back.
Second, for anything other than a documentary, the camera operator
wouldn't be adjusting focus. Lenses are at working aperture
(stopped-down), which can make it quite dark, and there are a lot of
other things to pay attention to during a take, such as framing, whether
or not the microphone is in the shot, and so on.
Third, the precision required is quite high, given that the images will
be blown up tremendously during projection. Any small error will
definitely show up.
Fourth, if the camera and lens are properly set up, measuring the focus
is much more accurate than trying to find it through the lens. I
shouldn't have to explain this one to M users.
Lastly (off the top of my head), many film set practices go back to the
dawn of cinema, and film crews are very conservative (as are producers
and investors). Measuring focus leads to fewer wasted shots, which means
fewer re-shoots, shorter days, etc. You really can't get much more
accurate and reliable than measuring tape.

Bernard