Is it possible to have a lens recoated??

TimothySchlauch wrote:

If the coatings was so easy messed up, then why would the makers go
through all that trouble to put them on. And giving that any pro
should know, how to clean glass and not mess them up in the first
place.

Coatings reduce reflections (which cause ghosts, flair,...) good coatings reduce these effects more than simple coatings.

A single coat of magnesium Flouride will reduce the reflectivity of a typical crown glass from 4% to 0.5% in green and 0.9% at the blue end 1.1% in red. This kind of coating is about 100 times softer than the glass surface.

There are multilayer dielectric coatings deposited in high vaccum chambers with electron gun sputtering techniques that are almost as hard as the glass surfaces they protect.

The military has access* to very resistant dielectric coatings they use on their optics that are harrd enough to be casually cleaned in the field with a wipe of a dirty shirt removing highly abrasive sand. These coatings cost about $10 per square inch and have a failure rate of 3-4% per coating run. (Failures get send back to polishing). A set of these kinds of coating on the lens set of a 24-70 would cost about as much as a 24-70 actually retails for!!!! I happen to have several eyepieces with these kind of coatings, and they are really good--making the typical multilayer coatings look like amateur attempts.

So how good are the coatings on the glass, it would seem that
cleaning 1000's of times the right way of course. Should never mess
them up, and that keeping them clean can only help them. As long as
you don't scratch them, when you clean them and use coating safe
clearner on them.

Proper cleaning techniques include never getting lens so dirty that the optical surfaces need to be touched in the first place.
--
Mitch

[ ] Only the military can afford the cost structure