[MF3D.FORUM:1685] Re: Using front shift to simulate camera movements?

["Don Lopp" <dlopp@xxxxxxxxxxxxxxx>]

I am still at a loss as to how this would work . firstlyb the angke covered
woulbe quite limmited. macro capabilities quite limmited .the presision
mountig of the mirrors and lenses would be a prblem for even ZEISS and after
all of that what would you get  that couldnot be gotten by normal means. I
am reminded of the apparently controversial discussion about deviation and
the gobblygook concerning the advisability of yes or no concerning the adv
isability of having inter-ocular control  in all first class viewers muddied
up by miss quotes more gobbly gook etc.DON
----- Original Message -----
From: "Tom Hubin" <thubin@xxxxxxxxx>
To: "Medium Format 3D Photography" <MF3D.Forum@xxxxxxxxxxxxx>
Sent: Monday, April 09, 2001 10:54 PM
Subject: [MF3D.FORUM:1656] Re: Using front shift to simulate camera
movements?


> Bill Glickman wrote:
> >
> > Matt,
> >
> > > 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
>
> >         Thanks for the suggestion Matt.  Have you ever tried this
before?
> > How is the results?  I would assume the mirors would introduce some
> > sharpness loss?   Also, how do you determine your interocular distances?
Is
> > it the measurement between the center of the mirors?
> >
>
> Hello Bill,
>
> The mirrors will only hurt the image quality if the mirrors are poor
> quality. You will need good quality first surface mirrors. You will need
> to keep them clean and damage free. Gentle and loving care just like for
> your camera lenses.
>
> Inexpensive aluminum mirrors reflect about 85% of the light. Some
> mirrors with better coatings can reflect more light, more like 95% or
> 98%. Get info on light losses and make sure that is ok before you invest
> time or money in the wrong mirrors. You will need high reflectance
> mirrors if you shoot in low lighting and cannot afford to give any light
> up.
>
> The interocular distance is, for practical purposes, the mirror
> sepertion. The way it actually works is to draw a line from the subject
> to the mirror and then add to it the distance from mirror to lens. This
> locates the image of the lens as seen from the subject. Since the
> mirrors are very close to the camera, compared to the distance to the
> subject, the interocular distance is just a touch more then the distance
> between mirror centers.
>
> If you do this with more than one mirror per camera then the seperation
> of the mirrors nearest the subject will, as a practical matter,
> determine the interocular.
>
> If you do this for close subjects then the interocular needs to be
> determined more rigorously.
>
> Tom Hubin
> thubin@xxxxxxxxx
>
>