P3D Re: Newbie questions

[michaelk@xxxxxxxxxxxxxxxxxx (Michael Kersenbrock)]

> I remember back in the olden days that you could buy stereo adapters that 
> would mount on the front of your lens, essentially providing stereo 
> half-frame images on a 35mm slide or negative.
> 
> I am interested in finding or constructing such a device, but can't seem 
> to find any information. I hope the list can help.

As of a year or two ago, Pentax still sold their adapter (which they
have mfgr'd by someone else now), but at an obscene price (which they
"have to" due to the low volume... a catch-22).

> 
> Related to this, I would like to do some stereo photography with my zoom 
> lenses (19-35 and 28-200). Would the same device work for my zooms that 
> works on a 50mm lens? (Zooms take huge filters -- 72mm and 77mm.)

Not generally.  One I had tried with a mirror that adjusts really didn't
help like I'd had hoped (and it had back-silvered mirrors unlike the better 
front-silvered Pentax mirrors).  Mount sizes also are a bit limited else the 
mirrors would get really big (as well as probably having other design
problems).

As others will say, it's easier/cheaper to just buy a Realist (or the like)
camera than to use a splitter.  If it's the convienence that's being sought
rather than a low-priced entry, then get an RBT S1 Camera from Jon, it's
autofocus, auto-everything with sharp lenses.  Love to have one, but it
costs a little bit more than even a typical 2D SLR.  Well, a BIG bit more.

Splitter-Camera's autofocus likely won't work (focusing on a "center stripe"), 
although the auto-exposure worked for some (and not others).

> I've seen all sorts of information about figuring stereo base that depend 
> on focal length and subject distance. Is all this necessary? Or is it 
> possible to take decent stereo photos without all the math?

That stuff is usually just for photos where the subject is less than a few
feet from the camera.  Otherwise, not really.  Just helps in special-cases.

> 

The splitter has a good niche in that one can have very fast stereo camera
shutter speeds without the expense of an RBT camera or the expense/size/weight
of twin-SLR's.  But that's about the limit to which it's best at.  I had used
my pentax one for many many years.


Mike (back from family reunion in Vegas) K.


P.S. - I only took 8 or 9 stereo rolls while there (took FED this time).  Mostly
       family pic's but a few other things as well (like a live Klingon).




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