I was wondering if anyone has mounted the medium format slides in super
slide format and projected it in a TDC 116 which can handle the 40x40
image. Any thoughts about how that would do? That way I can use a MF
pair for projection without getting a medium format projection set up.
I know I'd lose half the area, but it would still be bigger than a
standard full frame.

Just wondering,

Grant

Probably, since there were at least 4 127 format stereo cameras made
that I'm aware of. There was the Coronet (probably not the best camera
for chromes), the Ernemann Stereo Bob, the Stereo Hit and a 127
version of the rolleidoscop.

http://www.onetwoseven.org.uk/cameras/coronet/stereo
http://www.phsne.org/ralphs_3d_page/ralph's_3d_page.html
http://www.phsne.org/ralphs_3d_page/camera/rolleidoscop.html

--- In MF3D-group@yahoogroups.com, "Grant Campos"
wrote:

>
> I was wondering if anyone has mounted the medium format slides in super
> slide format and projected it in a TDC 116 which can handle the 40x40
> image. Any thoughts about how that would do? That way I can use a MF
> pair for projection without getting a medium format projection set up.
> I know I'd lose half the area, but it would still be bigger than a
> standard full frame.
>
> Just wondering,
>
> Grant
>

--- In MF3D-group@yahoogroups.com, "Grant Campos"
wrote:

>
> I was wondering if anyone has mounted the medium format slides in

super

> slide format and projected it in a TDC 116 which can handle the

40x40

> image. Any thoughts about how that would do? That way I can use

a MF

> pair for projection without getting a medium format projection set

up.

> I know I'd lose half the area, but it would still be bigger than a
> standard full frame.

I spent considerable time working with superslides. The big
advantage is that you can use 2x2x2 viewers and 2x2 projectors.
Other than twinning 1950s TLRs (or SLR in the case of the Komaflex),
to my knowledge there's no "quality" stereo camera made for
superslides. The pre-War 45x107 plate cameras will produce
superslide images, but all of those cameras have uncoated lenses
that won't produce images that will stand up to the magnification of
the average 2x2x2 viewer. Plus their rollfilm backs, which are
quite rare, do not have pressure plates. Most of my superslide
images were cropped from Sputnik exposures, which are very nice
since in most cases you're cropping the center of the image - which
is the sharpest. They looked real good in 2x2x2 viewers. I even
looked into using a 2x2x2 drum viewer - until 3D World came out with
their line. Being that the 3D World drum viewer and STL viewers
were so much cheaper than equivalent 2x2x2 equipment, it just
doesn't pay to go down the superslide road anymore for me. I'm
still considering twinning 127 TLRs for some special projects
though. Oh and I did project superslides with a pair of
projectors. They do look great, but you're still stuck with the
same projection issues - e.g. ghosting, alignment, etc. that you are
with 2x2x2 projection. Kodak Ektagraphic projectors will vignette
the image as well. My Simda projectors do not - but they're not
being made anymore. I did not try it out with the TDC projector,
but I believe that that's a one at a time manual operation with
superslides, and I'm not interested in fiddling with individual
slides in front of an impatient audience (myself included). If
you're interested in finding slide mounts, 127 film, etc. you can
contact me offline as I have information on all of that stuff.
Steve

--- In MF3D-group@yahoogroups.com, "radiomaan" wrote:

> Probably, since there were at least 4 127 format stereo cameras
> made that I'm aware of. There was the Coronet (probably not the
> best camera for chromes)

The Coronet's meniscus lenses are not adequately stopped down for
it's long (I believe 3") focal length, yielding very poor image
quality.

>, the Ernemann Stereo Bob

The Ernemann, along with all 45x107 plate era cameras uses uncoated
lenses.

>, the Stereo Hit

The Stereo Hit does not have adequate stops for slide film
exposures. It was made for prints and delivers "Bantam" i.e. 3x4cm
sized images - not superslides.

> and a 127 version of the rolleidoscop.

I won't argue with Rolleidoscop fans - but Rolleidoscop's also use
uncoated lenses. Unfortunately most pre-War 45x107 cameras used
four element lenses. They were at the time very expensive cameras
and so there was no need to skimp on the lenses. However to make
one of these into a "user" camera you would need to coat the
lenses. In the case of the Tessar, the rear element would have to
be separated and re-cemented as part of this process adding
considerable expense. Had they used three element Cooke lenses
instead, it would have made coating these lenses that much easier.
Is anyone aware of a 45x107 camera that used three element lenses?

Steve

--- In MF3D-group@yahoogroups.com, "coronet3d" wrote:

> However to make
> one of these into a "user" camera you would need to coat the
> lenses. In the case of the Tessar, the rear element would have to
> be separated and re-cemented as part of this process adding
> considerable expense.
>
> Steve
>

According to my telescope making manuals, cemented elements are
normally cemented with a type of oil that acts as an anti-reflection
coating on the surfaces involved, so the cemented elements would not
need their facing surfaces coated. I am uncertain if the
magnesium-fluorite coating process would require the separation (i.e.
oil vapor pressures might interfere with the necessary vacuum).

- Bruce

coronet3d wrote:

> --- In MF3D-group@yahoogroups.com, "radiomaan" wrote:
> > and a 127 version of the rolleidoscop.
>
> I won't argue with Rolleidoscop fans - but Rolleidoscop's also use
> uncoated lenses. Unfortunately most pre-War 45x107 cameras used
> four element lenses. They were at the time very expensive cameras
> and so there was no need to skimp on the lenses. However to make
> one of these into a "user" camera you would need to coat the
> lenses. In the case of the Tessar, the rear element would have to
> be separated and re-cemented as part of this process adding
> considerable expense. Had they used three element Cooke lenses
> instead, it would have made coating these lenses that much easier.
> Is anyone aware of a 45x107 camera that used three element lenses?

I'm not sure what you are referring to with "skimp" above.

Anti-reflective coatings didn't exist until just before WWII. In
Germany (where Zeiss had developed their coating in 1935)
anti-reflective coatings were considered a military secret.

Early lens coatings were "soft" and easily damaged. Hard coating
(which are more practical for consumer use) didn't show up until Kodak
developed their coatings during or just after WWII.

You'll do fine with a good lens shade on an uncoated Tessar lens so
long as you don't include a light source in the field of view. (Hint:
if your lens shade has a round opening it isn't blocking all the stray
light.)

A Tessar doesn't have any more air/glass surfaces than a Cooke
Triplet. Zoom lenses with large numbers of air/glass surfaces are
where coatings become necessary.

Recoating a lens (whether or not it has cemented elements) isn't
really practical.

--
Brian Reynolds | "Dee Dee! Don't touch that button!"
reynolds@panix.com | "Oooh!"
http://www.panix.com/~reynolds | -- Dexter and Dee Dee
NAR# 54438 | "Dexter's Laboratory"

radiomaan wrote:

> --- In MF3D-group@yahoogroups.com, "coronet3d" wrote:
> > However to make
> > one of these into a "user" camera you would need to coat the
> > lenses. In the case of the Tessar, the rear element would have to
> > be separated and re-cemented as part of this process adding
> > considerable expense.
>
> According to my telescope making manuals, cemented elements are
> normally cemented with a type of oil that acts as an anti-reflection
> coating on the surfaces involved, so the cemented elements would not
> need their facing surfaces coated. I am uncertain if the
> magnesium-fluorite coating process would require the separation (i.e.
> oil vapor pressures might interfere with the necessary vacuum).

That's an oil spaced lens group (as opposed to an air spaced group).
The oil does not act as a glue. It's used because it has a different
refractive index and gives the lens designer another way to tweak the
design. You can think of two elements seperated by a gap as a
triplet, glass/gap/glass. Using air or oil in the gap lets you vary
the refractive index of the center element in that group.

Older lenses were cemented with Canada Balsam. Balsam has a
refractive index that is close to that of glass. Balsam can yellow,
and I think it is one of the things that fungus likes to live off of
in lenses. The waste from the fungus is what causes the crazing of
the glass surfaces. You can separate a pair of elements glued
together with Balsam, but there's a good chance you'll damange the
lens elements.

Modern lenses are cemented with a UV activated glue. This glue does
not yellow and fungus won't eat it. I'm fairly sure you can't
separate elements cemented with this glue.

--
Brian Reynolds | "Dee Dee! Don't touch that button!"
reynolds@panix.com | "Oooh!"
http://www.panix.com/~reynolds | -- Dexter and Dee Dee
NAR# 54438 | "Dexter's Laboratory"

--- In MF3D-group@yahoogroups.com, Brian Reynolds wrote:

> I'm not sure what you are referring to with "skimp" above.
>

They did *not* "skimp" - in other words nearly all pre-War 45x107
cameras have pretty much the best available lenses at the time. Of
course none of them were coated.

> Anti-reflective coatings didn't exist until just before WWII. In
> Germany (where Zeiss had developed their coating in 1935)
> anti-reflective coatings were considered a military secret.

H. Dennis Taylor of Cooke and Taylor-Taylor Hobson discovered the
concept of lens coating. I'm not sure that Zeiss was the first to
use it in production lenses, but of course their reputation for lens
and coating innovation is unparalleled.

> Early lens coatings were "soft" and easily damaged. Hard coating
> (which are more practical for consumer use) didn't show up until

Kodak

> developed their coatings during or just after WWII.
>
> You'll do fine with a good lens shade on an uncoated Tessar lens so
> long as you don't include a light source in the field of view.

(Hint:

> if your lens shade has a round opening it isn't blocking all the

stray

> light.)

Wrong - this is good for the kind of flare you get from having
bright objects (e.g. the sun) just outside the scene. This does not
help from the kind of flare that dampens contrast via light bouncing
around in the lens. This kind of flare is most noticeable in
smaller formats under greater magnification such as 45x107 which not
that much larger than 35mm. Coating made 35mm a viable format. You
can see the same flare effects in vintage glass plates that you'll
see in my chromes made using Richard Verascopes (with various
lenses). The only case where I don't see flare is one vintage glass
plate I own of the interior of a church. My guess is that the image
was push processed (which increases contrast - reducing the impact
of flare) or that the long exposure time somehow compensated for the
flare effect.

> A Tessar doesn't have any more air/glass surfaces than a Cooke
> Triplet. Zoom lenses with large numbers of air/glass surfaces are
> where coatings become necessary.

Correct, but a uncoated Tessar will have more reflections than a
Triplet because of the cemented rear doublet.

> Recoating a lens (whether or not it has cemented elements) isn't
> really practical.
>

It's expensive but doable. Lenses mounted in 45x107 cameras can be
easily disassembled as the lenses are screwed in as opposed to the
Sputnik where they're held together with rings and such. The rear
element in a Tessar adds cost to the process, whose price of course
has to be doubled in the case of a stereo camera.
Steve