I have no experience with Medium Format stereo, but I have a lot of
experience with 35mm stereo, so here is my take regarding different focal
length lenses in standard stereo cameras.

I have an RBT camera (75mm lens spacing) that takes Pentax lenses and have
accumulated a wire range of lenses from 16mm to 300mm (someone can translate
these to MF equivalents).

My favorite lens in a stereo camera is the 35-40mm lens. (In the RBT camera
it is a pair of 40mm pancake lenses. My other RBT camera has fixed 35mm
lenses).

*** Wide Angle lenses (sort FL):

I never understood the fascination with wide angle stereo photography.
People are paying a lot of money to buy the Steinheil attachment for their
Stereo Realist that converts the 35mm lenses to 24mm. I don't see the point
really. Even the rather common 28mm seems too wide for me.

My pride and joy are the 20mm Pentax lenses. I paid $400/a lens for these.
I tried them for ordinary 3d photography and was rather disappointed. I am
actually thinking of selling them now.

These very wide lenses need the proper subject. You can take stunning 3d
photographs if you have the right subject. They are not for general purpose
3d photography, in my opinion. I know other people disagree and love wide
angle 3d photography.

*** Telephoto (long FL) lenses

These are also specialty lenses. No one is going to go around shooting
ordinary subjects with long lenses. For me, a medium long lens (80 to 135mm)
will work well with portraits or whenever you want to isolate your subject
while being at some distance from it.

Longer lenses are good to have around, but are not going to be used often.
One exception is twin cameras. For twin cameras and wildlife and other
similar subjects, long lenses can be very useful, but the standard stereo
camera has too narrow stereo base for these lenses to be used properly (just
like Sam described).

*** FL conversion lens attachments

I have tried these in my RBT camera with the fixed FL lenses, and, as others
said, the results were disappointing. Too much distortion, chromatic
aberration, etc. It is not worth the effort IMO.

*** The Bottom Line (for me)

I went to Hawaii this summer with a heavy photo camera bag, filled with
lenses. I got the best results with the 35 or 40mm lenses. Next time I
would think twice before traveling with all these lenses that I am not going
to use.

I would not modify a stereo camera permanently to take anything other than a
standard or slightly wide lens, unless if I really need to work with a
subject for which these lenses are more suitable (portraits, for example).

George Themelis

A decent pair of zooms, and perhaps two telextenders may be all that anyone
needs for most situations
I learned a long time ago that having mounds of equipment does not a good
photographer
make. In all forms of photography the only thing that ultimately counts is
the image.

Marshall

----- Original Message -----
From: "DrT (George Themelis)" <drt-3d@att.net>
To: <MF3D-group@yahoogroups.com>
Sent: Thursday, December 06, 2007 3:00 PM
Subject: [MF3D-group] My experience with different FL lenses (Re: Wide
Angled Lenses on TL-120)


>I have no experience with Medium Format stereo, but I have a lot of
> experience with 35mm stereo, so here is my take regarding different focal
> length lenses in standard stereo cameras.
>
> I have an RBT camera (75mm lens spacing) that takes Pentax lenses and have
> accumulated a wire range of lenses from 16mm to 300mm (someone can
> translate
> these to MF equivalents).
>
> My favorite lens in a stereo camera is the 35-40mm lens. (In the RBT
> camera
> it is a pair of 40mm pancake lenses. My other RBT camera has fixed 35mm
> lenses).
>
> *** Wide Angle lenses (sort FL):
>
> I never understood the fascination with wide angle stereo photography.
> People are paying a lot of money to buy the Steinheil attachment for their
> Stereo Realist that converts the 35mm lenses to 24mm. I don't see the
> point
> really. Even the rather common 28mm seems too wide for me.
>
> My pride and joy are the 20mm Pentax lenses. I paid $400/a lens for these.
> I tried them for ordinary 3d photography and was rather disappointed. I
> am
> actually thinking of selling them now.
>
> These very wide lenses need the proper subject. You can take stunning 3d
> photographs if you have the right subject. They are not for general
> purpose
> 3d photography, in my opinion. I know other people disagree and love wide
> angle 3d photography.
>
> *** Telephoto (long FL) lenses
>
> These are also specialty lenses. No one is going to go around shooting
> ordinary subjects with long lenses. For me, a medium long lens (80 to
> 135mm)
> will work well with portraits or whenever you want to isolate your subject
> while being at some distance from it.
>
> Longer lenses are good to have around, but are not going to be used often.
> One exception is twin cameras. For twin cameras and wildlife and other
> similar subjects, long lenses can be very useful, but the standard stereo
> camera has too narrow stereo base for these lenses to be used properly
> (just
> like Sam described).
>
> *** FL conversion lens attachments
>
> I have tried these in my RBT camera with the fixed FL lenses, and, as
> others
> said, the results were disappointing. Too much distortion, chromatic
> aberration, etc. It is not worth the effort IMO.
>
> *** The Bottom Line (for me)
>
> I went to Hawaii this summer with a heavy photo camera bag, filled with
> lenses. I got the best results with the 35 or 40mm lenses. Next time I
> would think twice before traveling with all these lenses that I am not
> going
> to use.
>
> I would not modify a stereo camera permanently to take anything other than
> a
> standard or slightly wide lens, unless if I really need to work with a
> subject for which these lenses are more suitable (portraits, for example).
>
> George Themelis
>
>
>
>
> Yahoo! Groups Links
>
>
>

--- In MF3D-group@yahoogroups.com, "DrT \(George Themelis\)"
wrote:

>
> I never understood the fascination with wide angle stereo photography.

In MF3D there are several advantages of moderate wide angle lenses
that may not be apparent to those who have not used them. The 55mm
lenses I use are the rough equivalent to 28mm lenses in 35mm an reveal
no major distortions as you would see in those approaching "fisheye"
designation.

Here's the benefits:

1. The 55s make the TL-120 almost point-and-shoot. No focusing is
required, as it is fixed at the 12' distance. If your exposure is
predetermined (such as a sunny day), you simply point and click. Great
for candids. One of the big complaints about MF3D is the time it takes
to get ready to just take a picture. Anything that cuts this down is a
bonus.

2. Depth of field is far more desirable for MF3D. Most have noted the
flaw with the current 80mm lenses is that they limited to a minimum
aperture of F22. 55mm lenses accomplish at F16 what 80mm lenses get at
F22. But the extra bonus is that you can stop down to f32 if you need
to. Can't do that with the supplied 80s.

3. Obviously, more in the picture. For scenics and interiors you never
seem to have enough room to get it all in. Remember, you can always
crop an image you've taken, but if the full subject isn't there in the
first place you're SOL.

4. Using 55mm lenses is COMPLETELY REVERSIBLE. You are simply removing
the lens board and replacing it with a new one. You can even do this
with film in the camera!

I see only one major disadvantage. I know the early models of the
TLR-120 have the apertures directly linked to the meter. If this is
the case, the meter won't give an accurate ready. For me this is not
an issue, as I always use a handheld meter or guess by experience.

Sam

Hi!

Thanks a lot, everybody!!! It gave me a good overview on your
experiences with wideangle lenses! So, I think I`ll not try these
stuff and waste some money!

Dear Oleg! A very interesting idea to put some 180mm lenses on a
camera rig with more distance between the cameras! I will try this out!

Dear Sam! How did you do the conversion with the 55mm Mamiya lenses?
Were did you get the additional lensboard for the TL120? Or did you
just hacked your standard lensboard, that was delivered with the
camera? Can you send some details about this conversion?

Thanks a lot and kindest regards to everyone loving 3D! Chris