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P3D Re: Lens Matching


  • From: "Greg Wageman" <gjw@xxxxxxxxxx>
  • Subject: P3D Re: Lens Matching
  • Date: Fri, 23 Oct 1998 20:38:38 -0700

From: Bob_Maxey@xxxxxxxxxxxx <Bob_Maxey@xxxxxxxxxxxx>


>Actually, I think the above is true. I only thought that since the
>equipment used to make lenses is so sophisticated these days, there is
a
>better chance of getting closer matched lenses today, than 20 years ago
or
>so. After all, manufacturing equipment for optics is highly
sophisticated,
>and when a particular lens  design works for a manufacturer, they are
not
>likely to build it on equipment that has the habit of falling out of
>tolerance.


Is it really that sophisticated?  If things have changed, I'd like to
know about it.  Last I knew, lenses were still made in the "traditional"
way by grinding molded blanks down to the desired profile using
progressively finer grades of abrasives.  (This obviously does not apply
to polycarbonate and other non-glass lenses.)  If anyone has any
information otherwise, I for one would sure like to know!

>I know that some manufacturers of professional motion picture equipment
>often goes to great lengths to insure that their lenses are suitably
>matched

And Hollywood has more than sufficient funds to pay for the $ervice.
Semi-pro and consumer lenses are under heavy price competition, so
there's no incentive to hold to tolerances any tighter than necessary
for good *single* lens performance.  I'm sure the manufacturers have
more than a single machine making the various optical components, even
of the same type.  If the tolerances of two machines are at the opposite
limits of the tolerance band...

>It might be an interesting experiment. In the mean time, there is the
RBT
>Cameras and those who use dual cameras on a bar. Chime in all you users
and
>tell us what you have discovered about this.


The RBT zoom lenses are matched on an optical bench.  The coupling is
custom-set on each pair.

     -Greg W. (gjw@xxxxxxxxxx)



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