From: fiddler@concertina.Eng.Sun.COM (steve hix)
Newsgroups: rec.photo
Subject: Re: polycarbonate camera bodies
Date: 12 Aug 92 18:37:47 GMT
Organization: Sun Microsystems, Mt. View, Ca.
NNTP-Posting-Host: concertina

In article <1992Aug11.205256.16290@midway.uchicago.edu> ar12@midway.uchicago.edu writes:
>The trend towards polycarbonate bodies/gears/lenses (yes, Cannon is trying
>to pawn plastic lenses on undiscriminating consumers) is NOT as most
>camera sales critters would have you beleive, that polycarbonate is more
>durable. 

There are plastic lenses and there are plastic lenses...

You need to differentiate between plastic lens elements (probably a Bad Thing),
and plastic replacing more or less of the previously-metal parts of the
lens' body.

And yet again, there's plastic and there's plastic.

>The ONLY reason is that polycarbonate can be injection moulded
>whereas aluminum/titanium/etc. cannot. 

Some types of die-casting can be a pretty good equivalent, though.

>Now, anyone care to guess the
>difference in manufacturing costs between injection moulding 50,000 bodies
>and die-casting? 

Very few metal-bodied cameras were completely die-cast...and they tended to
be heavy and expensive.  I know, I own some.  I like mine, too.  But...

There are some real advantages to using high-strength plastics in some
(probably a lot) parts of camera bodies.  Ever seen dents in a plastic
body's prism housing?  It takes a much harder whack to dent the body of
my T90 than parts of my F-1's.  For some applications, the plastic makes
more sense than metal, having benefits both to the buyer and the maker.

Perhaps you'd prefer that new high-end cameras be made completely of metal
and forego all use of plastic, even where it makes sense.

Be ready to write bigger checks.

>Of interest may also be the warnings issued with longer
>(heavier) lenses against their use on certain polycarbonate camera bodies
>(Cannon in particular does not recommend use of certain of its lenses on
>anything less than the EOS1- which likewise is no construction heavyweight).

The parts of the EOS-1 that count, such as the mount and shutter/mirror box
structure, are metal, not plastic.

I suspect that the warnings are to avoid liability concerns when someone
grabs their camera attached to their (huge, expensive) 400/2.8 by the
camera body, and are suprised when the weight of the lens rips the lens
mount out of the body.

It doesn't matter *what* the body is made of, that sort of abuse will
trash most cameras.

>Now I hear that Nikon doesn't recommend certain lenses for use with
>their polycarb bodies- now, alothou most of us won't be using these $3000+
>beauties, I think the point is evident.                         

Maybe you ought to thank the lawyers, instead, for making explicit
what photographers using big, heavy lenses have know for decades: the
camera is not a handle for big glass. (I can hardly believe that I said
that...)




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