[MF3D.FORUM:1179] Re: First roll run through the mysteryWhutnikstereo

[Brian Reynolds <reynolds@xxxxxxxxx>]

Bill Glickman wrote:
>      I guess you can accomplish the same thing by shooting a grid on the
> wall then projecting the chromes and measuring the difference in the worst
> area then divide by the magnification factor to see how far off two lenses
> are, right?
> 
>     Also, I guess you could just print trannies and overlay them... I may
> have to try that....
> 

There is another, possibly easier, way.  To do this you need a
(possibly unusual) reversing ring that has a filter thread on both
sides.

Attach the lenses to each other with the reversing ring.  Put an
illuminated target one focal length (as measured on the camera body
for infinity focus) behind one lens and a screen behind the other
lens.  Focus the image on the screen.  Measure the distance from the
lens to the screen and from the other lens to the target.  They should
be the same.

If you have an enlarger that you can mount the lens pair on all you
have to do is put the target in the negative holder and focus on the
base board.  I haven't thought this through, but you might get more
accuracy by magnifying the image of the target (by raising the
enlarger head).

-- 
Brian Reynolds                  | "Dee Dee!  Don't touch that button!"
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http://www.panix.com/~reynolds  |    -- Dexter and Dee Dee
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