This raises the whole question of how one can determine whether a lens
is multi-coated. I've heard lots of people refer to the colors of the
reflections, as though the presence of several different colors shows
MC. I don't see why that would be true. In the case of the design of a
lens before MC, the designer would still want to balance the color
response of the lens. If all surfaces were given the same coating
thickness, the lens would have significantly higher transmittance around
the color most effected by that coating thickness, resulting in a lens
with unnatural color balance. Would not the designer use different
thicknesses of coating on different surfaces to achieve a roughly
balanced transmittance across the visible spectrum? Of course, they must
have done so based on the color characteristics of the lenses produced.
Since the color of the reflection from a SC lens surface is determined
by the subtraction of light around the effective range of the coating
thickness, this results in different colored reflections from different
lens surfaces.
It is further true that individual MC coatings are not equally effective
across the whole spectrum. A 2 layer coating can only be even
theoretically fully effective at 3 wavelengths, and possibly only 2 in
many actual applications. So MC lenses continue to have multiple
different colored reflections.
I have gazed into the depths of at least 3 pairs of Zuiko lenses to
compare SC to MC reflections. Although there were some (surprisingly
smaller than I expected) differences in the color of the various sizes
and depths of reflections, the most noticeable difference was the
clearly lower overall brightness of the reflections of the MC lenses,
vs. the SCs.
Thus, the only absolute determinant of MC is either an 'MC' marking or a
serial number higher than those of earlier examples of the same lens
that were marked MC. Nonetheless, I suspect that the 'x.ZUIKO' vs.
'Zuiko' markings are a more accurate indicator than guesswork based on
reflection color gazing.
Moose
Julian Davies wrote:
I've not personally seen one, but there are brochure listings of fast wides
(always mc) with element letters. I believe this is also true of the
180/2.8. The element letter / MC equation seems to work for lenses where the
coating strategy changed, but is only an approximation. The actual marking
was market - driven. Originally Oly were following N*k*n with element count.
At the time this was supposed to be the indicator of quality. They then
switched horses to following P*nt*x with MC markings, as this was the
flavour of the month. Eventually they grew up and just marked the lenses as
Zuiko, and let the brand be the indicator of quality. The actual coatings
did not always follow the branding, so...
If it's marked MC - it's MC
If not, it may be MC, you need to look. Some lenses got all the way from
X.Zuiko to Zuiko without passing go. egg 200/5 and 135/3.5. Some of these
are MC (allegedly - I've never found one).
Some lenses got MC and X.Zuiko, even when they started as SC. I have an
X.Zuiko 50/1.4 which is MC (but different from those marked MC)
Some lenses got re - formulated at the time of going MC, egg 85/2.
Then there are repairs and upgrades. Makes you want to: 1.Weep. 2. Collect.
Thank goodness that Oly were less prolific in versioning than most..
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