P3D Lens Coatings

[Eric Goldstein <egoldste@xxxxxx>]

Cross-posting this from another list (rollei users group)...

A few weeks ago a question was raised with regard to the lens coatings
on our cameras and whether they could be cleaned off or abraided or
damaged by cleaning...

My own experience/research matches the information below. Before the mid
50s, the lens coatings of most manufacturers I'm aware of were very
vulverable to and could be damaged by almost any contact, including
cleaning. Be very careful!

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>   Early coatings were indeed soft.  The very first ones used by Kodak, in
> the late 1930's were so soft they could be removed by cleaning so were
> applied only to inner surfaces.  Lenses for the ill-stared Ektra camera
> were coated this way.  Really hard coatings probably weren't available
> until the early or mid fifties.  Curiously, I have a pair of Bausch & Lomb
> Navy binoculars made in 1943 which are hard-coated on the outer surfaces.
> I have seen other such glases which carried a warning lable (gone on mine)
> saying they were coated and to be careful when cleaning.
>   I think the general disruption of things in Germany following the war
> probably delayed the coating of German made lenses for a time.
>   The idea of coatings originated with H.D.Taylor, the inventor of the
> Cooke Triplet, who noticed that old, tarnished lenses had higher
> transmission than freshly pollished ones.  Practical coatings had to wait
> for the end of WW-2 and the application of modern high-vacuum deposition
> technology.
> ----
> Richard Knoppow
> Los Angeles,Ca.
> dickburk@xxxxxxxxxxxxx

----

Also, practical full spectrum multicoating technology didn't reach the
consumer market till the late 60s/early 70s via joint research from
Zeiss and Pentax.

eg


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