[MF3D.FORUM:625] Re: Thanks Paul

["Bill Glickman" <bglick@xxxxxxxx>]

Don

You wrote:

> I am at a lossas to what MTF has to do with medium format stereo.  Don

      The MTF curve of a lens, (given by the manufacturer) shows the
apertures that will produce the greatest contrast and resolution for that
lens.  If you use LF lenses and try to shoot at f8, you will usually get
poor results vs. shooting at f22.  The reason is, all LF lenses are designed
with their sweet spots at f16, f22 and f32, while the wide apertures are
made strictly to view the ground glass.   LF lenses are made for studio and
landscapes primarily, not fashion and weddings like MF lenses are designed
around.

       MF glass is optimized at wider apt., say 4.0 to 11 or sometimes even
16.   Therefore you can shoot at faster shutter speeds to prevent blur and
produce the best images that lens can produce.   So it seems sensible to me,
that MF lenses are the "ideal" stereo lenses to use.  Of course, if one
wants to shoot 35mm,  mostly all 35mm glass is optimized at the wider
apertures.

      Of course, DOF limits still need to be respected regardless of the
type of lens being used.  But considering slight blurs area so exaggerated
looking through a viewer vs. a print, a few extra stops can make a huge
difference!

Regards
Bill G



> ----- Original Message -----
> From: "Bill Glickman" <bglick@xxxxxxxx>
> To: "Medium Format 3D Photography" <MF3D.Forum@xxxxxxxxxxxxx>
> Sent: Monday, May 29, 2000 10:07 PM
> Subject: [MF3D.FORUM:613] Re: Thanks Paul
>
>
> > Stuart
> >
> > You wrote:
> >
> > > By the way kevin,  I really hope you consider DUAL cameras as you will
> > have
> > > even more enjoyable results if the two images are snapped at the same
> > time.
> > > The little differences that pop up (literally) when using a slide bar
> can
> > > ruin an otherwise good picture.  The mind instantly recognizes
> > imperfections
> > > like a leaf out of position, a flag furled differently, etc...
> >
> >          I have been contemplating this exact issue.  Maybe you can
offer
> me
> > some insight.  I have two M7's now, and my missing link is the inability
> to
> > snap both shots at once when the camera spacing needs to be 65mm.  (Due
to
> > the cameras inability to get this close)  I was wondering when shooting
> > landscapes shots, how critical this is... From what you write above, it
> > sounds like even the slightest leaf or branch being out of place will
play
> > havoc with ones ability to fuse subjects.  I kind of suspected this, but
> > have no base for comparison, since I never had the ability to try this
> both
> > ways.   Do you find that snapping both shots at once is critical some of
> the
> > time, most of time or almost all the time?  Thats what I am trying to
get
> > the feel for....  Any input in this area would be very helpful...
> >
> > I can probably guess this dual firing is very critical.... if so, what
are
> > some recommendations on newer MF camers that can acheive the critical
65mm
> > spacing, can be fired siumltaneously and also offer interchangeable
> lenses?
> > It seems most of the new box type cameras by Mamiya, Hassy, Rollei,
> Bronica,
> > etc. are way to big,  preventing the desired 65mm spacing.
> >
> > If I were to mount my two M7 80mm lenses on a view camera lens board,
they
> > still will not be 65mm apart, but can get to about 70mm.  Will this
extra
> > 5mm spacing ruin the desired effect?  Or would it go un noticed as long
as
> I
> > am not shooting very close objects, like 3ft.   If this is feasible, I
> would
> > consider putting 2 M7 mounts in a Toyo lens board,  focus via the ground
> > glass, and then insert a 6x12 roll film holder (with a slight bit of
> > modification) and get two 6x6 chromes.  Of course I would need a light
> > divider inside the bellows.  I can link the shutters electronically.
> > I have considered using LF lenses, but they will not get much closer,
and
> > they do not seem as ideal as MF glass since the MTF curves on LF lenses
> are
> > not optimized until f16 and higher, while  MF glass is optimized at the
> > wider and faster apertures... and speed seems a great advantage in MF
3d.
> >
> > Any holes in my thinking?
> >
> > Regards
> > Bill G
> >
> >
>