[MF3D.FORUM:1332] Re: Larger aperture size for twin rig shots?

["Don Lopp" <dlopp@xxxxxxxxxxxxxxx>]

I am at a loss to understand how one can successfully utilize a 7 ft window
with M F stereo. Depth of focus rquires at least f 32 or f45 and I think the
resulting picture would be quite hyper which I find troubling as I have
indicated before.The minimum stereo base  is limitted toapproximately 60mm
if 00 shutters are used and 70 mm if 0 shutters are used. I donot like to
bring up the subject of deviation again because I can not prove any thing
using E mail. I would not be surprised to see some examples of this problem
in  Paul T folio ?? which might prove my conservative views to be wrong .As
I said before, one can spray flat black paint on the inside of the white MF
slide masks whih coverts them into the black masks which will convert them
into the black masks which will be available in the future. My morphine mind
is foggy enough that I donot understand what Paul T  is asking for.-- Don
----- Original Message -----
From: "Greg Erler" <greg.erker@xxxxxxxx>
To: "Medium Format 3D Photography" <MF3D.Forum@xxxxxxxxxxxxx>
Sent: Sunday, November 12, 2000 8:23 PM
Subject: [MF3D.FORUM:1330] Re: Larger aperture size for twin rig shots?


>   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
> >
>
>