Re: More thoughts on formats

[P3D Michael Kersenbrock <michaelk@xxxxxxxxxxx>]

> > In the standard 7-perf camera progression, there is one frame
> > between each frame being exposed.  So 2 x 7 x 4.75 = 66.5 mm
> > and that is the nominal lens spacing on a 7P camera.  66.5 is 
> > much closer to the average human eye spacing than 71.25.  So
>  
> That's the spacing of the images on the film,....
> ... This means the 5P would have a lens separation
> of 71.2 - 1.2 or around 70.  Most (all?) 7P cameras are not the

Both of these postings are talking about certain implementations
of 5P cameras as if it were inherent to the format, although
John B. started to say this, then took a step back in the
quoted portion.

I know of at least one 5P "realist format" camera that has a 
closer spacing in the low/mid 60's of mm (don't recall the figure
off hand).  It's the TDC Vivid.  It has a little loop in the
film path between the exposure windows to make the spacing of
the images on the film design-independent of the separation of
the lens system.  The "loop" takes up the slack due to the 
lenses being closer together.

Mike K.


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