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Re: [OM] zuiko 100 2.8

Subject: Re: [OM] zuiko 100 2.8
From: Moose <olymoose@xxxxxxxxxxxxx>
Date: Fri, 18 Apr 2003 13:44:50 -0700
I agree with your comments, including that coatings changed on at least some SC lenses over their production lifetime. As to the conclusion based on 'reflection gazing' (Remember waht happened to Narcissus!) about number of coatings, I'm not so sure. Repeating myself from an earlier 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

AG Schnozz wrote:

I would suggest that not all silver-nosed 100/2.8s are created
equal.  Mine has many more coatings than other single-coated
lenses, but doesn't possess the "green" reflection that
everybody put in to signify that it was a multicoated lens.




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