Russian Beam Splitter for 3D Photography

<p>I have an old Russian-made beam splitter that screws to the filter threads of the front of a lens. The intructions

state that it is designed for a 58mm lens. I guess it was made for the old Helios 58mm "normal" lenses that were

used on Zenit cameras. The device comes with adapters for 49mm and 52mm thread size, so that part is good

for using it on my Nikon and Canon SLR's. However, my lenses are 50mm, not 58mm. My questions: 1) Will

that make much difference as to the perspective of the final images? 2) I plan to use a filter between the front of the

lens and the beam splitter. Will that increase the focal length a bit to make it more like a 58mm lens? 3) If not, is

there some type of adapter or ring I can buy to effectively turn the 50mm lens in to a 58mm? Thanks in advance for

the advice!</p>

<p>The important thing with any beam splitter, from my long ago experience, is to get the right amount but not too much line between the two images and little overlap if possible bleed into each other. Distance is one but not the only variable in that. If you are using a film camera, then you may want to put something like waxed paper stretched across in the film plane to see how broad the center line is in real time and then move it, the splitter back and forth, the unit I mean... <br>

The goal is to have enough picture image to see in the pair with some-but not too- much space in between if I make myself clear. <br>

If it is a good front surface mirror ( no douvle reflection) or better yet prisms you should have little trouble getting a good result. A bubble level on the camera and one gently cemented on the splitter will give you confidence that the unit is level. You want it to stay level at all times. Beyond that, experiment, and have fun. <br>

Pentax made the most recent quality splitter for their film cameras, so maybe that might get you off on the research on line in Pentax land...<br>

I have not had good luck with the low cost Chinese models.<br>

You know, of course, that you can buy a real serious used 3- D camera for about 125.00 or so. Check KEH camera brokers or write to this gentleman who knows his stuff big time:<br>

http://home.att.net/~drt-3d/</p>