So, just exactly what is the difference between a 180/2.8 Zuiko
with a serial number less than 200000 and one with a serial number
greater than 200000 that causes the literature (see the esif) to
say the 1.4X-A teleconverter is intended for use only with the
higher-numbered lenses? When this subject was discussed some time
ago, it ended with no definite answer, just the guess that there
must have been, might have been, could have been an optical design
change. The literature even says as much. Maybe so, but it
appears just as likely the reason is mechanical rather than
optical. Here?s why I say that:
I've had my No. 111xxx 180/2.8 for years, and last year I "won" a
1.4X-A off eventualBay at a fairly reasonable price, intending it
mainly for use with the 300 and 400 Zuikos. Naturally, being the
curious sort, I tried it with the 180 too, but only casually and
hand-held -- off-handedly, you might say. The results seemed
okay. But last week, to finish off the remaining 15 frames on a
36-exp. roll of Fujichrome Provia 100F that I wanted to get
processed right away, I decided to really test this non-
recommended combination under more rigorous and controlled
conditions: OM-4Ti, tripod-mounted, aperture and shutter prefire,
etc.,. and so on. The resulting slides, examined with both 10X
and 20X loupes, are tack-sharp and distortion-free,
indistinguishable from shots made with this lens without the
teleconverter.
However--and you knew there had to be a "however" --I found that
when focusing to infinity, instead of the usual solid stop and
Zuiko "thock" when the infinity mark is reached, there was some
interference just a smidgen before that point and infinity focus
was now silent and a little soft. (I realize "smidgen" is a
technical term, and for those not totally up to date, in layman's
language, it's roughly equal to about a hair and a half or so.)
Careful and thorough investigation revealed that there's a metal
baffle behind the rear element of the 180 that comes into very
slight contact with the edge of the metal ring around the front
element of the teleconverter at infinity focus. No big deal; it's
not glass-to-glass, just metal-to-metal, and it's only a half a
hair or so of contact occurring a mere smidgen from full infinity
focus.
So there! Mystery solved? Maybe, maybe not. It could be that
just moving the metal baffle was considered by Olympus to be an
optical change. Anyway, I?m satisfied, and since the 180 is
always in my "go" bag, now the 1.4X-A will be too. And anybody
who's got one of the pre-200000 180/2.8 lenses shouldn't hesitate
to use or get (no connection to anything that might be for sale
anywhere) the 1.4X-A. Despite the slight interference, it still
focuses to infinity.
And besides, how often do you need to do that anyway? What's out
there, really? But that's a question that would definitely start
an OT discussion, so I'm not going there.
Walt Wayman
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