Re: More camera ideas and questions

[Stephen Kearney <slk@xxxxxxxxxx>]

> Is there any reason not to put the lenses at the ortho spacing and let
> the window fall where it will?  I seem to remember doing these
> calculations a while ago, but I don't have my notes or the formula
> handy.  Given that the 4x5 lens I'd be most likely to use has a
> shutter that is 3 inches in diameter getting a 75mm spacing is more
> likely.

If you don't get the camera lens to film gate geometry right then you'll just
end up fixing it when you mount your pictures. And if it's really out of whack
you might not be able to slide the film chips enough to set the window.
Basically the camera lenses need to be spaced slightly narrower than the film
gate centers.

I just took some measurements off my Sputnik: Lens spacing = 63mm, film gate
centers = 64mm apart, film gate width = 55mm, L + space + R image = 120mm wide.
According to the formula the window falls at 4.7 meters. I usually set it
closer when I mount my pictures (using the latitude provided by the fact that
the film chip images are larger than the mount apertures. Anyway it does look
like you can make the geometry work (barely) if your lenses are small enough to
be at 63mm spacing. My 2x3 press camera lenses are mounted in shutters that
allow a minimum spacing of around 58mm.

Also keep in mind that using longer focal length lenses will be non-ortho,
unless your viewer has the same, and will set the window farther out.

All this said, I have to add that the Sputnik really isn't that bad a camera. I
just got a roll of film back and was struck by how good the images are. Just
stay at f/16 and it's actually very usable.

> I have Graflex Optar 135mm lens (my first LF lens), and had planned on
> getting a second for 4x5 full sheet stereo (either two 4x5 holders, or
> 8x10 with a cut darkslide to allow multiple exposures on a single
> sheet and lots of rise on the back or a revolving/repositionable
> back).  I'm not sure if I'll go that route anymore (I'd have to build
> a viewer).

I'm not sure I'd recommend LF stereo. It was a grand experiment for me but the
MF stereo is a much more practical system with excellent quality.

_____________________________________
 Stephen Kearney : mailto:slk@xxxxxxxxxx
http://jimkearney.ne.mediaone.net/~slk
           Oakland, California