cjss@xxxxxxxxxxxxx wrote:
>>it happens that the switch in styling from silver nose to
>>black nose roughly coincided in time with the optical switch to
>>multi-coating.
>>
>>
>
>Not necessarily... that may be the case for the 50/1.4 (AFAIK, the first of
>the non-macro 50s to be MC), but some lenses (like the fast wides) were MC
>from the start -- even the silvernosed samples. OTOH, some other lenses
>(28/3.5, 135/3.5) were never made multicoated, even in blacknose. I think
>the silvernose->blacknose switch was made around 1977-1978, no matter the
>coatings used, and the generalization of MC (new ZUIKO nomenclature) was
>around 1983.
>
My very brief comment was meant to supplement the eSIF page I posted a
link to, not to stand on its own. My point, made much clearer in the
heading I reference in the eSIF page, was that the 2 events overlapped
on a lens by lens basis, but were not related. That's what you are
saying, too, but in such a way that it sounds like I was not.
>I believe the X.ZUIKO / ZUIKO MC / ZUIKO marking scheme (SC / MC / MC) to
>be a safer way to tell a multicoated lens --
>
Yes, exactly what it says on the part of the eSIF I referenced.
>but still not 100% safe! I had
>a ZUIKO 135mm 1:3,5 (last nomenclature) whose reflections looked the same
>as the E.ZUIKO 1:3,5 f=135mm (first scheme, surely SC).
>
>Judging SC/MC by looking at the colours of the reflections is NOT easy.
>*Theoretically*, SC reflections bear 'secondary' colours (purple,
>yellow-gold, light blue) and MC reflections show 'primary' colours (deep
>blue, red, green). BUT if you see together the, say, red reflection on a MC
>surface with the green reflection of another MC surface, you'll get a
>*yellow* reflection, usually associated with SC
>
No. First, the 2 reflections will appear as different sizes. Second,
they will appear at different depths, meaning they will move relative to
each other as the angle at which they are viewed changes.
>... Plus, the colour of these reflections may shift depending on the angle.
>
Not in my experience in spending too much time gazing deep into lenses
looking at reflections.
I believe, based on empirical experience, that most of this reflection
'knowledge' is inaccurate speculation. To quote myself from 8/2003:
"I do question the value of the reflection color stuff. I had both SC
and MC examples of the 21/3.5 and 24/2.8 lenses. I peered deeply into
them side by side. The colors of the reflections were remarkably similar
within each pair. The marked difference between SC and MC was not color,
but brightness. The MC reflections were much less bright than the SC
reflections. I speculated at some length on the reasons why this would
be so in a prior post, if anybody is interested.
I don't see how this reflection stuff can be much use, since side by
side comparisons mostly won't be possible. Yes, green and magenta
reflections exist in some SC lenses."
And the prior post:
"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."
The earilest SC lenses tend to show overall yellow reflections, while
later ones show a number of different colors. This certainly shows the
results of improvements in coating technology and sophictication, but
not necessarily in the number of coatings. My SC 100/2.8, ser. 110,9xx
shows what seem to be more than one shade of yellow, a pink and a
magenta reflection. The overall brightness of the reflections is clearly
in the SC camp."
Moose
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