[MF3D.FORUM:489] Exact fl match for paired lenses.

["Bill Glickman" <bglick@xxxxxxxx>]

I recently bought a second Mamiya 80mm lens. Now I can now shoot with 2
bodies side by side with a dual cable release.  I realize that lenses must
be identical fl on each camera for proper stereo viewing.  And the labeled
fl can vary from batch to batch.  These were purchased 2 years apart.

1.  What is the best way to determine if this lens matches my other 80mm
lens?
2.  How close does the match have to be?  +/- 1%
3.  What is the effect in the viewer when lenses are not identical, but are
within say 1%?  Is there some break point where things become noticeable,
like greater than 2% for example...

Thank you for your help ...

Regards
Bill G