The simple reason that SC lenses weigh more is because there are more
reflections inside a SC-coated lens. MC-coated lenses allow the light to
pass through without bouncing around. All those reflections in the SC lens
cause the light to stay in the lens longer and it will then weigh more with
a SC lens. On a really long lens this might add up to 30-40 mg., easily the
difference in published weight. If you are taking photos in red light
(George S.?) the lens would be even heavier since red light has a longer
wave length. On the other hand, blue light might stack up more in the lens.
Hmmm, I have to think more on that one! Could someone help me with this?
This SC-MC question can also be verified by disassembling the lenses and
weighing the various components. An excellent lens would be the 35mm shift.
Then, reassemble the lens without the components, weigh, and then
reassemble.
Olaf just got a good buy on a 35mm shift, perhaps he could help us out since
he's also had experience taking lenses apart.
Brian P. Huber
bphuber@xxxxxxxxxx
Troy, OH
-----Original Message-----
From: owner-olympus@xxxxxxxxxxxxxxx [mailto:owner-olympus@xxxxxxxxxxxxxxx]
On Behalf Of ALEXSCIFI@xxxxxxx
Sent: Saturday, June 05, 1999 10:15 PM
To: olympus@xxxxxxxxxxxxxxx
Subject: Re: [OM] Brainstorm--SC vs MC
I am utterly certain that there is no detectable difference in weight
or mass of SC versus MC. The reason that MC lenses "generally" out-test and
out perform SC lenses has to do with a phenomena called "scatter"--whereby
when light hits a lens surface, all of it does not go through! Some is
bounced back to scatter through the other elements in the opposite
direction,
causing a reduction in contrast. Moreover this bouceback usually varies with
frequency (color). If I recall correctly no coating results in a scatter of
some 5 to 10 percent, sc reduces this to 1 percent or so, while MC reduces
this to tenths of a percent.
I cannot remember who discovered it but SC usually means a coating of
Magnesium Fluoride(?), which was in and of itself a vast improvement over
"no" coating at all! In the 70s (think Austin Powers), Pentax came up with
what they called "Super Multi Coating" which improved on the SC still
further! They (and Zeiss) are still regarded as the best of that technology.
Alex
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