[MF3D.FORUM:1681] Re: Using front shift to simulate camera movements?

["Don Lopp" <dlopp@xxxxxxxxxxxxxxx>]

Tom . if I am wrong ,please tell me wh at angle of field I can expect t be
able to utilize . i do not epect it to be very much by normal stereo
standards by which I do not consioder View Master a decent standard. DON.
----- Original Message -----
From: "Tom Hubin" <thubin@xxxxxxxxx>
To: "Medium Format 3D Photography" <MF3D.Forum@xxxxxxxxxxxxx>
Sent: Tuesday, April 10, 2001 8:40 AM
Subject: [MF3D.FORUM:1664] Re: Using front shift to simulate camera
movements?


> Hello Don,
>
> Not true. It depends entirely on how you do it. If you connect all
> points on the subject to all points on the lens and the mirror
> intersects all of those rays then you loose nothing.
>
> For stereo there is a practical limit on this single mirror approach.
> The system is creating the illusion that the lenses are side by side
> with the camera bodies overlapping. They cannot appear closer than
> touching each other without clipping something. For example, if the
> lenses are 50mm diameter then 50mm is the smallest interocular that you
> can create without clipping.
>
> To avoid clipping at 45 degrees you need a mirror that is the square
> root of 2 larger in the folded dimension. So a minimum of 50mm by 71mm
> ellipse would be needed in the above example.
>
> Tom Hubin
> thubin@xxxxxxxxx
>
> **************************************
>
> Don Lopp wrote:
> >
> > Plus the angle covered would be relatively narrow DON
>
> > ----- Original Message -----
> > From: "Bill Glickman" <bglick@xxxxxxxx>
> > To: "Medium Format 3D Photography" <MF3D.Forum@xxxxxxxxxxxxx>
> > Sent: Wednesday, April 11, 2001 12:31 AM
> > Subject: [MF3D.FORUM:1657] Re: Using front shift to simulate camera
> > movements?
> >
> > > Tom
> > >
> > >         I'm not understanding this....  If you look forward you see an
> > > image, if you turn 90 deg and use one mirror at 45 deg, you will see
the
> > > same image.  So why wouldn't the film see the same thing looking in
the
> > > mirror?  Are you sure you would have to view the slide with the
emulsion
> > > side away from our eyes to get the same effect as if the cameras shot
> > > straight at the scene?  Hmmmm..if so, that does not sound good, but
then
> > > again we look straight through the slides anyway?
> > >
> > > Bill g
> > >
> > > > Clever idea but the images will be mirrored. So you will need to
print
> > > > with the emulsion side up or view slides with the emulsion side away
> > > > from the eye or project with the emulsion side away from the screen.
> > > > This will reduce the quality of the image.
> > > >
> > > > A pair (or any even number) of mirrors for each camera is more
> > > > complicated but would avoid the mirror image problem. For that
matter,
> > > > two mirrors on one camera and no mirrors on the other camera would
also
> > > > work. But then the distance from camera lens to subject is not the
same
> > > > for both cameras.
> > > >
> > > > Tom Hubin
> > > > thubin@xxxxxxxxx
> > > >
> > > > **********************************
> > > >
> > > > Matthew V. Ellsworth wrote:
> > > > >
> > > > > Bill
> > > > > I'm not sure if I'm understanding what you want to do, but maybe
this
> > > idea will
> > > > > help:
> > > > > Two cameras can be mounted facing each other on an adjustable
rail --
> > > with a
> > > > > small front-surface mirror mounted at a 45 degree angle in front
of
> > each
> > > lens.
> > > > > This allows you to get both cameras quite close (limited by the
size
> > of
> > > the
> > > > > mirrors), and allows easy access to the focusing and film advance
> > > mechanisms.
> > > > > Matt
> > > > >
> > > > > Bill Glickman wrote:
> > > > >
> > > > > >       I am trying to develop a MF camera system that allows one
to
> > set
> > > > > > interocular bases at any seperation without physical
> > > limitations.....As we
> > > > > > all know, this is physcially impossible sometimes with two non-
> > shift
> > > > > > cameras.  My idea was to use two cameras side by side, but each
one
> > > would
> > > > > > have the capability to shift the lens horizontally.   This has a
> > very
> > > > > > dramatic effect vs. spacing the cameras.  For example, I can
> > simulate
> > > 24"
> > > > > > interocular distance with only 3mm of front shift on one camera.
I
> > > have
> > > > > > tested this, it works.  So a small amount of lens shift would
> > simulate
> > > > > > interocular spacing fro 0 to 500 + ft.
> > > > > >
> > > > > >       I have found that myself and my audience all prefer very
small
> > > OFD's,
> > > > > > say 1.3mm, hence the need for bases much tigher than any two
cameras
> > > can
> > > > > > every physically acheive.   A fixed stereo camera (sputnicks)
don't
> > > appeal
> > > > > > to me because I want the flexibility of adjusting the
interocular
> > > distance
> > > > > > when required.
> > > > > >
> > > > > >         Although this sounds good in theory, I am curious if
this
> > will
> > > > > > produce the same stereo effect as utilizing two cameras at the
> > proper
> > > > > > interocular distance.  I don't plan to use it for excessive
bases,
> > > only for
> > > > > > 24" and less.  Has anyone every tried this before?  Any input?
> > > > > >
> > > > > > Bill G
> > > > >
> > > > > --
> > > > > ______ Matthew V. Ellsworth ______________________________
> > > > >       oakridge@xxxxxxxxxxxxx      http://www.oak-ridge.com
> > > >
> > >
> > >
>
>