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Old November 28, 2012, 04:47 PM   #8
wogpotter
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Join Date: September 27, 2004
Posts: 2,928
Quote:
The multi-coating used on camera lenses (scope lenses?) is a gelatin substance.
Since when may I ask?

I've been in the optics industy since the 1970's & never heard of any such thing.
There are coatings, & multi-layer coatings, but they are vacum deposited chemical & mineral deposits utterly devoid of anything remotely resembling "gelatin", or any other organic material.
http://en.wikipedia.org/wiki/Optical_coating

There are also "cements" used to bond together certain individual elements to produce a combination effect of high & low refractive index glasses & they were once something called "Canada Balsam" which is organic, but is emphatically not "gelatin".
http://en.wikipedia.org/wiki/Canada_balsam

More modern bonding & more advanced forms of optical glass have minimised this nowadays though.

Storing lenses in dark places will do absolutely nothing harmfull for ever, if just "dark" could harm lenses why aren't they destroyed by being stored on a camera with an opaque cap in place?

Now damp is harmfull to optics, fungus forms on the glass lens surface (coated or not it douesn't matter a bit), mites & micro-organisms can spread from rubbers & lubricants used elsewhere in the lens's mechanism & leave "cobweb" looking traces. Oils can migrate into areas where they shouldn't be forming "mirror pools" (gold colored patches & splotches), but absolutely none of this has anything whatever to do with fictional gelatin coatings which only exist as the emulsuion or backing of photographic film.

Quote:
Mold can and often does form on it,,,
You can clean it off but you will lose the anti-glare feature.
How do you clean off something that was never there in the first place?
You can accidentaly remove the bonded chemical layers with chemicals that wil attack the coating minerals, or just scrape it of abrasively by using incorrect, or grit impregnated cleaning materials. Only ever use the right materials & techniques & your lenses will remain coated, or multi-coated for aeons! Its not well known but optical glass is very, very soft & scratches easily. One side effec t of "Optical coating, or Multi-coating, or Super multi-coating" is anti-abrasion. The material is harder & more resistant to abrasion, but still softer than a grit-empragnated tissue, tie end, or shirt tail!

Coating does not primarily have an anti-glare function, it has some anti-glare as a secondary property, but its real purpose is to allow more light to pass through the optic's air/glass interface surface.

Quote:
Nikon, Canon, and Minolta all used the same stuff,,,
This has been a known issue since the 80's.
Actually Nikon (Nippon Kokaku K.K.) uses in house fabricated glasses & all proprietary coatings since the 1950's. (Nikkor glass works). They exclusively make & use thier own product, they do not sell outside if the Nikkor operation.
http://en.wikipedia.org/wiki/Nikon

Minolta also made (untill they closed & sold the rights to other companies) in house all its optical glass, blanks, elements & coatings, (Rokkor optical), but they do sell (or rather did sel untill they closed) to outside contractors, unlike Nikon who do not.
http://en.wikipedia.org/wiki/Minolta
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Last edited by wogpotter; November 28, 2012 at 05:08 PM.
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