Hello everybody
Below is a copy of a letter Gary Reese wrote to the list but which for some
strange reason never made it onto the server. Brian Swale
Hi Brian:
Here is something I wrote up which I regret didn't make it onto the List.
Perhaps you can repost it for me? Thanks for the offer.
Gary
*****************
Garry Lewis writes about my comments on the 35mm f/2.8 I posted as
< zuiko.sls.bc.ca/swright/archives/2000/msg01490.html >
"I'm mildly curious of Gary's reasons."
Mediocre close-up performance, with very low contrast of the outer zones,
even when stopped down. Probably excessive curvature of field is the main
cause, although this has the traditional edge performance problems we get
with retrofocus wide angle designs. The second cause is probably the
uncorrected aberrations typical of wide angle lenses at close range when they
don't have floating elements. At infinity, stopped down, the lens renders very
sharp images.
Regarding the ongoing 75-150mm debate [now died down]:
Historically, this is the 4th (or so) speculation here on the OM List
regarding the coatings of the 75-150mm. I suspect it won't be the last. It
generally arises because someone reads to deeply into the not sufficiently
technically edited The OM System Lens Handbook. I have unpublished data
on hand [not used in previous discussions] which can perhaps put this
debate to rest.
One of my reasons for being so sure that there isn't an MC version is that in
1983 there was a nomenclature change on the ID ring which went from
saying: 1:4 f=75~150mm to 75~150mm 1:4. 1983 was the year most
Zuikos got their "up"grade to Meade Green multicoating, along with the same
kind of nomenclature change and a brand change to reading just "Zuiko."
The 135mm f/3.5 is another example of the change in focal length and
aperture nomenclature, but no change in coating.
We are in 100 percent agreement that Meade Green multicoating doesn't
exist in either of these two lenses. Thus one can only speculate about one
or more elements having had a transitional MC coating of something other
than green.
Lets look at this from a cost approach. These were budget Zuikos. Olympus
wasn't about to sink money into multicoating redesigns of inexpensive lenses
nearing the end of the product life. As it was, the 135mm f/3.5 and 75-
150mm were discontinued in that important 1983 transition year, after short
production runs (all in 1983) bearing the new nomenclature. They had to be
discontinued so Olympus could say in advertising that the OM Zuikos were
multicoated across the full range of lens offerings. (But, we now know they
were very slow at getting around to adding some multicoated elements to the
35mm Shift. So they actually fibbed.) Additionally, Olympus was
standardizing on the Meade Green multicoating, so it was now a "go to the
latest coating technology, or else forget it" situation. They clearly said
"forget
it," on the 75-150 and the 135 f/3.5, since
1) the replacement 65-200mm f/4 was released in January 1984 concurrent
with discontinuing the 75-150, and
2) the 135mm f/3.5 ceased production in 1983 and remaining inventory took
until 1986 to sell - with no replacement.
A second reasoning for concluding there were no MC versions in the 75-
150mm or 135mm f/3.5 is that there were no serial number gaps for these
lenses over their 1982-3 change in ID ring nomenclature. Frequently there is
a small to large serial number gap when the coating was changed. The only
serial number gaps for these lenses was in 1978, at or near the point they
changed from chrome snout to black snout (at about serial number 235,000
in the 75-150mm and 207,000 in the 135mm f/3.5). There is no evidence
anyone has presented that the coating systematically changed from chrome
to black versions, or at those gaps. Nor, as I previously said, is there any
evidence that we picked up non-Meade Green multicoating in 1983 after the
nomenclature change.
Finally, there is the newly revealed problem of multicoating references in
the parts list for the 75-150mm. Well, there is no physical evidence that the
MC lens element references on the parts list ever saw the light of day
beyond a prototype or a proposed change. So, I continue to conclude that
1) Olympus kept these lenses single coated in the 1976 to 1982 transitional
evolution when they went from SC to early MC coating in many lenses,
2) they remained single coating in 1983 when other lenses got nomenclature
changes and Meade Green coating, and 3) both were probably under
consideration for multicoating (witness the change to "Zuiko" in the 135mm
f/3.5 in 1982) but plans got dropped.
Which makes sense: they were very low priced and had to stay that way to
be price attractive to the bulk of buyers into the OM System: the OM-10
users.
Gary Reese
Las Vegas, NV
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