Re: Novel Mounting Method

[bercov@xxxxxxxxxxx (John Bercovitz)]

Steve Spicer writes:

>> The bottom edge of the film gate could be modified so that the left gate
>> has one "reference" notch, and the right film gate has two notches - a
>> "near" and a "far" notch. The distance between the reference-notch and the
>> far-notch would be the same as the lense spacing (eg: 70mm in a Realist).
>> The distance between the reference-notch and the near-notch would be 1.2mm
>> more than the lense spacing - 71.2mm (for the Realist format).

Michael Kersenbrock writes:

> I'm confused.  How does this work?  Doesn't this put identical notches onto
> every slide without regard to the image?  Seems like this would only result
> in aligning the two "chips" at a fixed distance apart for all slides with
> the only "correction" going on being inter-image distance differences in
> different cameras (like the TDC Vivid being 65mm instead of 70mm) of the
> same format.  

First of all, I ought to say there are two philosophies of mounting slides.  
One is "mount to the window" and the other is "mount to infinity".  

In mounting to the window, you change the distance between the film clips 
so that the subject matter is in a pleasing position relative to the window.  
For instance, you might put the closest object just behind the window.  If 
you're having fun, you might set the clips so that something in the middle 
of the view is poking out through the window.

In mounting to infinity, you put infinity homologues the correct distance 
apart for the format, usually somewhere around 63.5 mm.  Now if you put a 
notch in each film gate directly behind each lens as Steve suggested, you 
will create an artificial pair of infinity homologues.  This pair can be used 
regardless of whether or not actual or convenient infinity homologues exist 
in the pair.

> Seems that if fixed spacing would work, then Kodalux machine mounting would
> work perfectly because I assume the chips themselves are machine aligned to
> constant distances apart.

You're right, it should and would if 1) all cameras had the same lens 
separation, as you point out above, and 2) if Kodak would take some care.  
>From what I've seen of their work, the worst of it is they often don't get 
the heights of the clips the same.  Of course sometimes they slop glue on 
the film and rarely they even mount a clip so far off center that there's 
daylight between it and the mount's aperture.  But mostly, it's height error 
that's their least forgivable problem, IMHO.

> Did I miss something (haven't had my coffee yet this morning)?

Sounds like you've missed your coffee.  8-)

John B


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