[MF3D.FORUM:1330] Re: Larger aperture size for twin rig shots?

["Greg Erler" <greg.erker@xxxxxxxx>]

  I'm just going to simplify.

  If you build a stereo camera and want the in-camera stereo
window to be at 7' or so you need to move the lenses together
by (roughly?) the on film deviation amount.

  So 2.5 or 2.7 mm closer together than the film gates should do
it.

  With separate cameras (aimed parallel) the "in-camera
window" is at infinity. So you waste the same 2.5 or 2.7mm
to mount them with a 7' stereo window.

  Thus with 55mm film gates you should be able to still
have 55-1.35mm or so of usable area. Any non-parallel aiming
of the cameras could easily waste 1mm or more so that might
be a bigger effect.

  Stereo base shouldn't matter if you keep the OFD under
control.

Greg E.

----- Original Message ----- 
From: "Paul Talbot" <ptww@xxxxxxxxx>
To: "Medium Format 3D Photography" <MF3D.Forum@xxxxxxxxxxxxx>
Sent: Saturday, November 11, 2000 8:55 AM
Subject: [MF3D.FORUM:1328] Larger aperture size for twin rig shots?


> There has been some discussion here in the past about
> the possibility of a larger aperture size 80x132
> mount for images from dual camera hypers.  Last night
> I was mounting a test shot taken with two MF (stereo)
> cameras on a bar.  I was amazed at how little room
> there was (in the 50mm aperture size mounts) for
> horizontal cropping of the hyper image, while keeping
> the stereo window in front of the scene.
> 
> The non-overlap area of twin camera shots really uses
> up a lot of the excess image area.  I haven't done any
> calculations to nail down specifics, but perhaps someone
> here could run a few numbers.  Assuming a 75mm FL lens,
> what is the widest aperture size that can be used to
> properly mount images assuming the image area on film
> is a) 55mm wide; b) 60mm wide; c) 65mm wide and the
> stereo base is a) 6 inches; b) 12 inches; c) 24 inches?
> 
> If no one is feeling ambitious enough to run all those
> numbers, how about one or two combinations and the formula
> to calculate the rest?  A spreadsheet would be nice.  ;-)
> 
> Paul Talbot
>