What is this crystal formation in the lens?

I wonder if anyone can tell me if the crystal formation in the lens shown in the picture attached to this topic is anything to be concerned about - it's in a pair of 1980's Carl Zeiss 10x50W binoculars - which other than this small blemish is perfect?

looks like a fungus to me....get it cleaned ....or it will etch the glass....

I agree with gunut, it looks like fungus. 

I have read that you may be able to clear small amounts of fungus by leaving it in the bright sunlight for a few days. 

I think you will find it is NOT a fungus but, rather, the elements of your objective beginning to seperate. Cory can easily fix that. Easy for him, but time consuming. Prepare to spend a little money. Attached is another photo of seperation.

Bill




Edited by WJC - March/25/2018 at 17:47

Good call, Bill. The shape and stark white color of the anomaly does look more like your example than what you normally see from fungus.

Yes, nice call and very interesting.

tahqua wrote: Yes, nice call and very interesting.

Thanks guys:

Having two moderators in a row like something I said is refreshing. It seems there’s always some who think I should offer touchy-feely, milquetoast comments so not to offend the soft hearted ... or headed. I get the impression some think I should be ashamed of the experience I have that others don’t. I didn’t set that as a goal; it just came with loving my profession. But there’s no way to have spent decades in optics, and knowing what you are talking about, without being (to some) an arrogant know-it-all.

Even so, those who come to such a conclusion have not walked in my shoes having spent 21 of those years addressing the many misconceptions about optics in general and binoculars in particular—a few times a day EACH workday. Thus, they can’t really understand that even my bullheaded methods are not always remembered. And the more politically correct you are the less likely you are to be taken seriously, considering binocular forums consist largely of one bad “opinion” after another. My whole shtick is to help my neighbor—sometimes saving him from himself. But then, with unfounded pontifications being easier to deal with than first-hand experience or research, I guess I will be easy pickin’s for those who thrive on thoughtless speculations ... no matter who it hurts.   

This topic wasn’t a lucky call. It was something we learned about—and how to correct—in the Navy’s optical “A” school and rarely a week went by at Captain’s without having to address the problem ... often having to explain to the customer why you just couldn’t “polish out” the problem, because it was sandwiched between two cemented lenses. “Deer in the headlights.”

Sorry for being overly sensitive. It’s just that I’m dealing with such an issue at this very moment on Cloudy Nights. Vicariously of course, since I’m not allowed to play.

Blessings,

Bill

PS With an objective focusing at the field stop, turning it toward the sun to remove the fungus (that wasn’t a fungus at all) might have melted part of that field stop, had it been made of plastic. I’ve seen that more than once. Having said that, I doubt if Phil is offended—he’s on Optics Talk, which says a great deal about his resiliency as does being a Texan.

Phil, what part of Texas?  

Edited by WJC - March/26/2018 at 14:15

Nice to see you back Bill.

Hi, Skip:

'Never been gone. OT is one of the forums I keep open on my "Big Mac."

Bill

No offense I'll offer anything if I think it helps.  I'm a little south of Houston. 

When you say elements separating are you talking about the lens coating or the actual glass lenses ungluing themselves from each other?  I've never seen anything like it on an optic. 

If it is the elements of his objective beginning to separate. Wouldn't that possibly be covered by Zeiss's warranty? Or was the warranty different in the 80s?

The objective of most binoculars consists of a crown and a flint element—usually Bk7 and F2 or F4. They are cemented together with Canada Balsam (not “Canadian” Balsam) or Norland 61 thermosetting adhesive. Some people say that the elements set with Norland are difficult to get apart. However, I find a 4-pound shop hammer on a concrete slab works wonders. The lens can never be used again but the stress relief is great. As you might guess working with Norland takes a great deal of patience.

There is a good chance that the reason you haven’t seen this before is that you haven’t worked with binos every day for decades.

Cheers,

Bill    

Sparky wrote: If it is the elements of his objective beginning to separate. Wouldn't that possibly be covered by Zeiss's warranty? Or was the warranty different in the 80s?

They don't cover anything before WWII and may point out that the lens was subjected to direct sunlight. You'll have to call.

Bill


Edited by WJC - March/29/2018 at 16:44