Having just invested in a new pair of Swarovski EL's I wanted to understand what the right cleaning solutions are for modern day coated lenses? Historically I had used a lens cleaning solution containg Alcohol Isopropyl but wonder if this is OK for current lens coatings or damages them. Any guidance appreciated.
Hi, Allen,
This is a topic of never-ending speculation and quasi ... fact. In 16 years of visiting binocular forums, I have NEVER offered practical realities of the matter without being followed immediately by some opto-newbie, with a magazine or a computer printout in his hand, offering NEWER or BETTER technology. It has always been a great ego pumper for those long on theories but short on practical experience. Yet, I will jump through the hoops, again.
These are some facts:
1) Given a few centuries, even purified water will etch glass.
2) Alcohol has been
ONE tool of professionals for over 150 years.
3)
IF the AR coatings are put on at the
correct thickness AND temperature there is
NO PROBLEM.
4) Even the simplest magnesium fluoride coatings are
HARDER THAN the glass beneath:
575 on the Knoop Hardness Scale Vs. 520 for Bk7 (Crown glass). Multi-coatings can make it harder.
5) The first layer of coatings is only 6-millionths of an inch thick and,
if not put on at the correct temperature, will be too soft to stay on when exposed to
LIGHT ABRASION. This causes the inexperienced to assume the coatings came off their cheap binoculars because of alcohol, a 1/32 mixture of ammonia, or acetone, which has also been used by professionals for years.
6) There are some realities. They were offered to the magic 3% who want more reality than opinion.
7) If you chose to clean your optics with horse dung, jet fuel, or sandpaper, you may not have the best results, but your understanding of optics vs. time-honored opto-nonsense will blossom.
Back in my hole, now. Bah, Humbug!
Cheers,
Bill
