tonal1
Established
Sorry, duplication!
*edit*
Not sure why the good message was deleted, and this one remained?
Anyways, I am looking for cleaning solutions for cleaning delicate optics such as the internal surfaces of older Leica lenses and viewfinder elements.
Thank you.
*edit*
Not sure why the good message was deleted, and this one remained?
Anyways, I am looking for cleaning solutions for cleaning delicate optics such as the internal surfaces of older Leica lenses and viewfinder elements.
Thank you.
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FallisPhoto
Veteran
Well, regardless of the duplication, either hydrogen peroxide or (if it's a Leica) a dilluted mix of 1 part hydrogen peroxide, 1 part ammonia and 12 parts distilled water (what Leica recommends for cleaning their soft coatings). Generally speaking though, it is not recommended that you get ammonia anywhere near a soft coating (apparently unless it is a Leica).
Edit: This is only for cleaning haze and fungus. If you are just cleaning other stuff, you'd use more traditional (and benign) cleaners (naptha and distilled water).
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tonal1
Established
Thanks for the good info. Would the hydrogen peroxide/ammonia be safe to use on semi-silvered surfaces as well?
Thanks a bunch.
Roger Hicks
Veteran
The original soft coatings were very soft indeed and could not be cleaned at all, but the term 'soft coating' is now used for 'old hard coatings that aren't as hard as modern hard coatings' -- which includes Leica's older coatings.
Cheers,
R.
Cheers,
R.
FallisPhoto
Veteran
That's a formula for removing fungus from lenses. It is not for general cleaning, only for removing fungus. There is NOTHING that is safe for cleaning semisilvered mirrors. Most of the less expensive semisilvered mirrors in cameras are made using depositied aluminum vapor. It can come off with just a puff of air, so you clean them at your own risk. If you have fungus on a semisilvered mirror though, you're probably looking at getting a new mirror. Sorry.
FallisPhoto
Veteran
To clarify, it seems simple now, but in the early 70s, Pentax discovered a way to bake their lenses that hardened lens coatings a lot and fused the lens coatings to the glass. Pretty much everyone jumped on the band wagon and hard coating was born. Incidentally, the way it became fused to the glass is what made multicoating possible. before this, any attempt to coat an already coated lens simply removed the former coating. Any lenses made before this breakthrough are, in general usage, referred to as "soft coated" now. Technically, a real soft coating is one made before Leica developed their process of coating lenses. It is not a good idea to get ammonia near any of these because the ammonia can, at very least, cause the coating to seperate from the glass. On the older lenses, that really were soft, the ammonia can literally eat the coatings away. On the really soft coated lenses, anything beyond flushing with distilled water should be avoided like the plague.
There is yet another type of coating. There is a type of "tarnish" that sometimes develops on older lenses. It most often looks like a mottled irridescent oil slick. This is a type of natural coating called a "bloomed lens." In the old days, some people discovered that it increased the light gathering ability of a lens, decreased lens flare and improved contrast. They came to be in very high demand among astronomers and photographers and early lens coatings were an attempt to artificially recreate this "bloom." They still turn up every now and then and, once again, anything beyond a gentle rinse with distilled water should be avoided like the plague with these.
Roger Hicks
Veteran
Multicoating was first used (on an experimental basis) by Zeiss during WW2; coating with vacuum-deposited magnesium fluoride (the classic material) was first described by Cartwright in 1939. The first production multicoated lens, as far as I am aware, was the original 35/1.4 Summilux.
Pentax's 'SMC' was a marketing triumph but involved no significant technological breakthroughs. Go to the Focal Encyclopaedia and you will see references to baking (for 'hard' coating) and to multicoating in the 1965 edition and possibly earlier: 1965 was the first edition that came to hand.
Cheers,
Roger
Pentax's 'SMC' was a marketing triumph but involved no significant technological breakthroughs. Go to the Focal Encyclopaedia and you will see references to baking (for 'hard' coating) and to multicoating in the 1965 edition and possibly earlier: 1965 was the first edition that came to hand.
Cheers,
Roger
FallisPhoto
Veteran
I guess that will teach me to listen to what Pentax says.