[MF3D.FORUM:48] Re: Apparent image size, MF verus

["Bill Glickman" <bglick@xxxxxxxx>]

Alan

     Your investigative work has been very helpful to many of us... thank
you... Now that you have confirmed some of my suspicions, I would like to
find out where all this information can lead us....

    I originaly posed this question to Paul since I was strugling to find a
high end MF stereo camera.  I only found the Dr. Glide MF stereo camera,
which in stereo mode only sells for about $10K.  (it is available as
Panormaic also, and is huge, bigger than a Fuji 6x17 pan camera)  Plus it
seems the manufacturer in Germany is still working glitches out of the
design and manufacturing process.  As with many other people, I would be
wary of buying such an expensive camera that may soon become a  museum
piece.  I do applaud the makers design and concept though...

   After viewing your Saturn viewer with Sputnik slides, I was impressed by
MF 3d, but not overwhelmed... I deducted this was from several reasons, but
the most important reason was the lack of immersive feel due to the apparent
image size.  I compared your Saturn to a $20 3d discovery viewer... and the
higher magnification lenses of the 3d discover made those small 35mm slides
appear larger than the sputnik slides in the Saturn viewer.  Of course the
film quality and photographic technique degraded the 3d discover images, but
for $8 per 12 pix cassette I am not complaining, however a few of the shots
were reasonably good, and this made me think the following...

    With all the technology enhancments that have occured in the past 5
years with film, scanners, photoshop and film recording devices, is it
possible, that using high end 35mm stereo cameras like the RBT, we can
produce a spectacular 3d images through a viewer... I am not ever suggesting
that a smaller format can win over a smaller format, but considering the
logistical problems of MF 3d cameras, lenses for viewers, etc... I figured
if I can get 35mm up to very high standards, it may be impossible to detect
the difference...  Here would be the plan...  shoot with high end 35mm
stereo, drum scan the chromes, perform any corrections inside photoshop,
output them to a high end film recorder that uses a special type electronic
transparency film that has even tighter grain than 25 ISO chrome film and
similar saturation of that of Provia F.  You can print the new chromes to
any size you want, that part I am not sure about... but if MF size makes the
whole system more feasible, then so be it... if 24 x 34 works just as well
and brings the price of the viewers down, than that may be the way to go...
My point is, with the magnifications we are talking about here, say up to 5x
max. including the possible film enlargement and the viewer lense
enlargement... I would find it hard to beleive any degredation would occur
at all - specially none that would be detectable under these small
enlargement factors...  The whole reason MF is used, is simply for larger
prints... but if you are making 4x6" prints, it is almost impossible to
distinguish the difference between MF and 35mm prints, all other things
considered equal, and normal shots... not some microscopic view of very tiny
items...

    So, is it possible, a more sensible approach - due to the limitations of
high quality  MF stereo cameras is to use high end 35mm, scan, enlarge and
print on super tight grain films... in addition to electronic films for film
recorders, you can also dupe on "dupe films" which have twice the grain
density as Velvia and even more saturated... (hard to beleive anything could
be more saturated than Velvia, but its out there)  Looking at this on a
light table, I would think I am right, but I think things change when you go
3d.  I am very new to 3d, so I am not taking anything for granted.

    I realize this appraoch is quite cumbersome for the average enthusiast
who wants to shoot some of thier own slides for home viewing.  However, I
was considering this approach to be something more commercial for marketing
3d high end stereo work, mainly landscapes, which I shoot in 2d.  I hope I
did not offend any MF'ers out there, I too am obssessed with format size, in
my other life (2d) I shoot mostly 8x10!

    So if this is feasable, what would be the logical steps to pursue next?
Determine optimum chrome size, viewer lens fl... etc..  of course we need to
be sure after optimizing the chrome size and viewer fl size that this
equates to a camera fl that is somewhere near normal...  Any input would be
helpful... thank you..

Bill Glickman


> Paul Talbot wrote:
>
> > > 2) A full frame 35mm slide in a 50mm lens viewer (ortho)
> >
> > I think you are assuming the full frame 35mm camera has a
> > 50mm shooting lens when you call the 50mm viewing lens
> > "ortho."  My chart used the FL of the Red Button viewer,
> > which is probably what most people use to view full frame
> > stereo images.  These images might be shot with twinned
> > point and shoots with 35mm lenses, or an RBT with 35-70mm
> > zoom lenses, or a variety of options in between.
>
> Yes, that's what I was assuming.  I was first trying to sort out the
> immersive effect (apparent image size) vs. format size.  So I chose a
> common starting point for all formats to be fair.
> What happened is that I realized that it is not really the format size
> that makes for an immersive feel, it is only the apparent image size.  I
> know this sounds so easy to figure out, but I (like others) never really
> could quantify whether the format size made the most difference or
> whether the magnification did.
>
> I can say now that magnification plays the larger role, and your format
> choice will be guided by grain size and viewer lens choices.
>
>
> > With the Red Button lenses the extra width of full frame seems
> > roughly equivalent to the extra height of MF.
>
> Kind of. It is very hard to get a full frame image in the Red Button
> that is sharp from edge to edge, especially with eyeglasses.  (BTW: my
> observations are based upon wearing eyeglasses, the most restrictive
> situation).
> So the ability to get 44mm f.l. lenses that will actually cover the
> format size is the issue with the Red Button.  The lost "height" in the
> rectangular format can play a factor in the immersive feel.
> I do have a full frame Realist viewer, and I will say that without
> eyeglasses it does have a very nice image, sort of immersive.  So I'm
> not negative on that combination.  It isn't very forgiving though for
> eyeglasses and eye spacing that is non-average.
> I'll go out on a limb and say that if one could get a 35mm f.l. Realist
> viewer with large enough dia. lenses to cover the full square realist
> format that it will have a more immersive feel to it than the full frame
> in a 44mm f.l. viewer.
>
> >
> > > As you go to larger film formats you should also match your viewing
lens
> > > to the camera lens.  So merely moving to a larger format does not
> > > guarantee a larger image, it depends on what lenses you are using.  As
> > > you move to larger formats than 6x6 (6x9 would be a larger format for
> > > this discussion) you need a different viewer design, and should use a
> > > longer f.l. lens.
> >
> > But if you have an 80mm lens on your 6x7 or 6x9 camera, then
> > the roughly 80mm FL of the SaturnSlide is "ortho" for those
> > images.
>
> Yes, that is true.  But the practicality of image coverage then comes
> into play.  You can get an 80mm f.l. lens to cover a 6x6 image, but it
> won't fully cover a 6x7 or 6x9.  So this brings in the issue of
> compromise.  If one is willing to give up full image coverage (corner to
> corner) and be satisfied with edge to edge coverage at the best (if
> that) then they will get a more immersive feel.
> But a 6x9 will not fit into a parallel view design viewer (without
> mirrors).
>
> It seems to me that less than full coverage isn't too great a
> compromise.
> I have a (experimental) focal length combination in my latest viewer
> design (posted earlier on this list) that is approx. 58 to 60mm using
> triple achromatic lenses.  I was originally doing this for the panoramic
> format mount.  It works well for coverage of the panoramic mount, makes
> the image look just like sitting in a movie theater watching a
> Super-Panavision movie.  But not much height, so not much immersion.
>
> With a Spicer mount (King Inn size) 6x6 it will cover just about edge to
> edge.  It is really just a round image that fills the entire view.  Now
> you do really get a feeling of immersion with this.  The height of the
> image is as important as the width to get this feeling.
>
> When you view the world you are sensing both width and height.  Walking
> into a wide room with a high ceiling does give a person a different
> feeling than the same room with a low ceiling.
>
> The lack of full image coverage plays a role in the immersive feel
> (something observed by others on this and Photo-3d).  If you get rid of
> the stereo window then you can uncover a larger film width to view.  You
> will also get rid of conflicting visual clues due to the window.
>
> Viewing with a window is preferred by some, and others don't mind the
> lack of any visible window at all.  (I'm not saying you should set a bad
> window and try to view it, that is not right at all!).
>
> It appears that for 6x6 King Inn mount images that you will need a f.l.
> of approx. 60mm to start getting an immersive feel.  You should use 60mm
> lenses on the camera to keep the perspective correct.
> This of course means lots of glass in your lenses, and lots of $$$. Also
> remember that edge sharpness may fall off a bit no matter how good your
> lenses are.
>
> I'm not sure I see any advantage to going to larger formats in this
> case.  The grain is not an issue for me on 6x6 images.
>
> > >
> > > I did some calculations similar to Pauls', then tested some of them
out
> > > with real viewers (I have lots of viewers).
> > >
> > > I assumed for fair comparison's sake that all calculations would be
> > > based upon the full format size (not mount mask size)
> >
> > That makes a big difference!  The standard MF mounts crop out
> > a lot of image area!
>
> Yes, that's one of my observations.  It is not the film format size as
> much as the realized mount mask size that affects the image size.  In
> 6x6 stereo we could get a larger image by trying to eliminate the causes
> of masking down.  Current cameras limit this, so the real change would
> have to be a correct camera design.  A correct MF camera design sets a
> proper window and has accurate vertical alignment.  Then we could use
> larger mask openings.  I wouldn't fault the format size as much as our
> equipment.
>
> --
> Alan Lewis
> mailto:3-d@xxxxxxxx
> http://members.home.net/3-d
> Serious viewers for Serious viewer's
> New stereo viewers & Stereo Wedding Photography
>
>