In the not so recent past, some questions were raised about formulation
changes in the 50/1.4 "MC" lenses related to their serial
numbers. According to Gary Reese, at some point the formulation changed
from only some of the groups being multi-coated to all of them at or over
the 1,000,000 serial number. It is also apparent that at or over 1,100,000
the "MC" marking was dropped from the lens ring. The block most in
question about whether it is before or after the reformulation that
multi-coats all the groups falls in the 1,000,000 to 1,100,000 serial
number block.
I now have three multi-coated 50/1.4's within three different serial number
blocks. The first is 789,###, the second 1,05#,###, and the third is
1,11#,###. Following are my conclusions after examining all three:
789,### Zuiko MC:
Through the front element, it shows purplish reflections with some green
ones internally. Through the rear element, it only shows purplish
reflections. The nature of the colors in the reflections is clearly
different between examination through the front and rear elements.
1,05#,### Zuiko MC:
Through the front element, it clearly shows green and purplish reflections
from a number of groups. Through the rear element, it shows the same type
of reflections as through the front element.
1,11#,### Zuiko:
Through the front element, it clearly shows green and purplish reflections
from a number of groups. Through the rear element, it shows the same type
of reflections as the front element.
Conclusions:
1. There was indeed a formulation change related to the multi-coating
between S/N 789,### and 1,05#,### for the 50/1.4 lenses.
2. The "Zuiko MC" marking remained unchanged at the time of the
formulation change. When exactly this occurred cannot be determined, but
is somewhere between the first two S/N's. A reset to S/N 1,000,000 has
logic to it, and this examination does not refute it.
Gary Reese:
Was your citing of this S/N break a hypothosis based on observation, or is
there reliable documentation of some type to support it?
3. At some point later the "MC" was dropped from the "Zuiko MC" marking
leaving only "Zuiko" on the lens ring. There is no correlation between the
multi-coating formulation change and the marking change. Thus far, only
those with S/N's over 1,100,000 are documented in the information I've
found as being marked this way.
4. Whether a lens is marked "Zuiko MC" or "Zuiko" (but _not_ "G.Zuiko") is
not a reliable test for determining its formulation. A serial number of
1,000,000 or higher, not 1,100,000 or higher, is more reliable in finding
the newer multi-coating formulation lenses as it is now apparent there are
some with S/N over 1,000,000, but under 1,100,000, with "Zuiko MC" markings.
5. Which formulation a particular 50/1.4 has is more accurately determined
by examining the color reflections through both the front and rear
elements. My guess is the first MC formulation will only show MC related
reflections (i.e. green) from examination through the front element, and
will only show single-coating type reflections through the rear
element. The second formulation shows MC type reflections through both the
front and rear elements.
6. All of the above presume the lens ring (and therefore the S/N) has not
been swapped or replaced.
-- John
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