I believe we have both semantic misunderstanding and technical
misunderstanding here.
I posit that when Bill says 'inconsistency' he means there are many
different reflection colors in the 50/1.8 (by the way, we still don't
know from the evidence presented which version is being discussed) and
pretty much all the same color on the 55/1.2
I further posit that Lee, like me, thought he meant poor process control
leading to coating which were inconsistent within and/or between batches
of the same element for the same lens.
As to the first supposition, I believe there may be a misapprehension
that consistency of reflective color is in some way indicative of
quality. The reverse is true. The earliest coated lenses had relatively
consistent reflection colors. Later SC formulas had more and more
different colors for the reasons I recently posted. All MC formulas
incorporate multiple colors. This multiplicity of colors of reflection
is a result of increasingly sophisticated and effective coating design
and technology, including better programs and faster computers to run
them on. The 55/1.2 is a relatively early SC coating design. The 50/1.8
miJ is a relatively late MC design.
As to the second supposition, I don't now believe that is what was meant.
whunter wrote:
Whoa.....Take a deep breath. Perhaps i should have used 'stand
alone' wording in anticipation of cut and paste out of context and out
of my control as in the thread now presenting from Lee. My original
post in specific response to Gwinn's comment and provided herewith for
context:
*****************************
One must factor:
- time period whence manufactured.
- where manufactured and the vendor for MC
There is an assumtion here that bears questioning. I am under the
impression that Oly manufactured and coated all their own lenses except
for the Cosina made zooms that were brought out with the OM2000. If
true, all this stuff about who may have done the work and whether the
'cheap' lenses were just contracted out to some junk shop would be moot.
The 50/1.8 miJ is in fact a very high quality lens with excellent
performance, superior to the 55/1.2 according to Gary's tests. It does
use plastic in places where it doesn't affect the optical performance
but may affect durability. The cost argument is essentially meaningless
in this context where a much older design is being compared to a much
newer one. Comparison of the 55/1.2 to the earliest version or 2 of the
50/1.8 would be more appropriate if this whole line of thinking had any
purpose related to evaluating the performance of lenses.
- evolutionary period for the 1.8 versus the 1.2 which is more
than an order of magnitude when adjusted to include the number of
units produced for each design X options for low cost bid for large
production runs versus small / custom lots.
Unexamined assumptions about design and production again.
Moose
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