Strange spaghetti-scratch pattern on internally fogged lens (Nikon EII) (1 Viewer)

[yarrellii]

I live in a pretty humid environment, so it’s not unusual to have non-sealed binoculars fogged internally, in this case a 8x30 Nikon EII. It’s not the first time I get it. But this morning I've got something I've never seen before.

Picture 1. This is what I usually get, a crescent of fog (actually, it's usually 2 crescents, or the reflection of one). I’ve got a very limited knowledge of optics construction, but judging from what I can see from the outside, I’d say they appear to be located more or less where the prisms are supposed to be.

But now the new (and puzzling thing).
Picture 2. Today, I’ve got a new thing: a perfectly round patch of fog on the inner side of the objective lens, right in the center.

Picture 3. And now comes the puzzling bit. As soon as the binoculars have gained temperature and the fogging was starting to dissipate, the circle of fog on the inner side of the objective lens has started shrinking, concentrating and gaining contrast. It has gone from a misty “dull grey” shade to a more contrasty and whitish fog that has revealed a pretty clear (and worrying, if I may say so) pattern, something like "spaghetti scratches", for lack of a better term. Have a close look at the central part of Picture 3.

Since the binoculars have never been disassembled, I assume the pattern that the fog has exposed has something to do with the last stages of polishing/cleaning of the lenses in the factory, it looks like the result of using some kind of brush, but this is pure speculation. So I assume it is a usual thing that normally does not get exposed. Actually, had I not stayed to see what became of the round patch of fog, I would have never been aware of it.

Maybe someone with a good knowledge of the workings of lenses and binocular building can shed a light and explain what's going on? (Bill, Henry, Gijs, etc.).

Truth be told, once the fog has finally disappeared, the EII have gone back to normal, and the view is lovely as always. While looking at an old vine on the verge of a field, a blackcap has just appeared on the FOV.

 

[DMW]

That looks odd. The obvious culprit is fungal growth, but I've not seen one which looks like that. Maybe balsam separation is another possibility, but I have no experience of that.

 

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I live in a pretty humid environment, so it’s not unusual to have non-sealed binoculars fogged internally, in this case a 8x30 Nikon EII. It’s not the first time I get it. But this morning I've got something I've never seen before.

Picture 1. This is what I usually get, a crescent of fog (actually, it's usually 2 crescents, or the reflection of one). I’ve got a very limited knowledge of optics construction, but judging from what I can see from the outside, I’d say they appear to be located more or less where the prisms are supposed to be.

But now the new (and puzzling thing).
Picture 2. Today, I’ve got a new thing: a perfectly round patch of fog on the inner side of the objective lens, right in the center.

Picture 3. And now comes the puzzling bit. As soon as the binoculars have gained temperature and the fogging was starting to dissipate, the circle of fog on the inner side of the objective lens has started shrinking, concentrating and gaining contrast. It has gone from a misty “dull grey” shade to a more contrasty and whitish fog that has revealed a pretty clear (and worrying, if I may say so) pattern, something like "spaghetti scratches", for lack of a better term. Have a close look at the central part of Picture 3.

Since the binoculars have never been disassembled, I assume the pattern that the fog has exposed has something to do with the last stages of polishing/cleaning of the lenses in the factory, it looks like the result of using some kind of brush, but this is pure speculation. So I assume it is a usual thing that normally does not get exposed. Actually, had I not stayed to see what became of the round patch of fog, I would have never been aware of it.

Maybe someone with a good knowledge of the workings of lenses and binocular building can shed a light and explain what's going on? (Bill, Henry, Gijs, etc.).

Truth be told, once the fog has finally disappeared, the EII have gone back to normal, and the view is lovely as always. While looking at an old vine on the verge of a field, a blackcap has just appeared on the FOV.

It looks like fungal growth to me. The dust inside your lenses is a good example of how an unsealed Porro like the EII sucks dust inside because of the accordion or bellows effect when you focus. You have to get them professionally cleaned every once in a while. An EII is not a good glass in a humid environment.

 

[yarrellii]

That looks odd. The obvious culprit is fungal growth, but I've not seen one which looks like that. Maybe balsam separation is another possibility, but I have no experience of that.

It looks like fungal growth to me. The dust inside your lenses is a good example of how an unsealed Porro like the EII sucks dust inside because of the accordion or bellows effect when you focus. You have to get them professionally cleaned every once in a while. An EII is not a good glass in a humid environment.View attachment 1370462View attachment 1370463

DMW, Dennis, thanks for the insight. Very helpful. Now that is worriying. The dust you mention and that you can see on picture 3 is actually on the outside surface of the lens, the binoculars are pretty clean inside.

But the puzzling bit is that:

• This appears right in the center of the lens, as you've seen in the picture, and not from the border of the lens.
• Even if you inspect the binoculars under a torch or under a bright light the lenses seem immaculate, and appear perfectly clean an free from any strange matter.
• This was only visible during a few instants, while the fog was disappearing, but not actually when the binoculars were fogged. As I've explained, it was only visible when the fog patch was nearly gone, at the very end of the process.

The binoculars are less than 3 years old. I've got limited experience with fungus on binoculars. I've seen it in very old devices. Do you think that it's possible for fungus to grow in such a short period of tim and to be perfectly invisible and only visible under those circumstances?
Thanks again for your ideas and comments.

 

[henry link]

This spot looks to me like it's on the back surface of the objective doublet or possibly the cementing between the two lenses. It's easy to remove the objective from this binocular. It just screws off where the objective cell meets the body. Be sure to make some kind of reference marks on the body and objective tube so you can screw it back to the same position for maintaining collimation. Once it's off you can determine whether the spot is on the back surface or between the lenses. If it's on the back it might just clean off. If it's in the cementing a pro will need to re-cement the lenses. I doubt that it's on a prism, but that should be apparent once the objective is removed.

I wouldn't worry about dust being sucked into the binocular. The sliding surfaces of the eyepiece tubes have a layer of lubricant between them which catches most dust. I've never had an unsealed Porro get dusty inside. The more typical problem is off gassing of lubricant eventually causing a film on the prism surfaces, whether the binocular is sealed or not.

 

[yarrellii]

This spot looks to me like it's on the back surface of the objective doublet or possibly the cementing between the two lenses. It's easy to remove the objective from this binocular. It just screws off where the tube meets the body. Be sure to make some kind of reference marks on the body and objective tube so you can screw it back to the same position for maintaining collimation. Once it's off you can determine whether the spot is on the back surface or between the lenses. If it's on the back it might just clean off. If it's in the cementing a pro will need to re-cement the lenses. I doubt that it's on a prism, but that should be apparent once the objective is removed.

I wouldn't worry about dust being sucked into the binocular. The sliding surfaces of the eyepiece tubes have a layer of lubricant between them which catches most dust. I've never had an unsealed Porro get dusty inside. The more typical problem is off gassing of lubricant eventually causing a film on the prism surfaces, whether the binocular is sealed or not.

Henry, thanks a lot for the information, this is really interesting. Having seen the fog (and not having a great background in optics) I would agree with you about the location. However, I don't think I feel confident enough to carry on the service you describe. I think I understand what you mean, but I simply fear I might cause more havoc than benefit to the EII. I service my bike, and back in the day I even learned how to lace bicycle wheels from scratch (rim, hub, spokes), but I have zero confidence in my binocular servicing skills.
If this was some sort of fungus, would it make any difference to keep them on a box with several silica gel bags or something of the like. Or maybe let them stand under the Sun one day for several hours so that the fungus "cooks" in the heat? (Maybe this is too stark a mesure, I don't know, never had fungus in a binocular). Thanks again.

 

[mpeace]

Condensation will concentrate on the minutest of differences on a surface, so a lens that has been wiped with a clean cloth and appears fine can still have condensation collect on otherwise imperceptible traces of cleaning fluid residue etc left on the lens. The spaghetti effect looks like wipe marks from a cloth that have textured some fine residue. I really wouldn't worry about it. But if you get the bins cleaned it may well disappear - or you get a different pattern.

 

[yarrellii]

The spaghetti effect looks like wipe marks from a cloth that have textured some fine residue.

My impression while watching it "live" is exactly what you refer to, like the marks left by a brush of some sort, but what really struck me was how very well defined they have appeared at a very particular moment. As you can see on Picture 2, when the patch of fog covered a larger area of the lens, it was an homogeneous layer of condensation (like the mirror on the bathroom while you take a shower), but as it was shrinking, it suddenly sort of "cristalised" in that particular pattern. Your explanation sounds plausible. Thanks again!!

 

[henry link]

I don't want to get you in trouble, but really removing the objective and putting it back on is no more difficult than removing the lid from a jar of pickles and replacing it. Just remember to make the alignment marks or use pieces of tape if you decide to take a chance.

I like mpeace's explanation of what causes the pattern.

 

[yarrellii]

I don't want to get you in trouble, but really removing the objective and putting it back on is no more difficult than removing the lid from a jar of pickles and replacing it. Just remember to make the alignment marks or use pieces of tape if you decide to take a chance.

I like mpeace's explanation of what causes the pattern.

Hehe, I just have to love that example you gave. Well, I'll open the jar of pickles Thank you very much!!!!

 

[Binastro]

Although the markings are strange, it doesn't look like a normal fungus pattern.

I have numerous cases of fungus in binoculars bought from charity shops or private sellers.
I am surprised you have had no fungus in binoculars.

I have had dozens of camera lenses with fungus.
Old Olympus lenses seem like a leader with this issue, but most makes suffer.

Old Nikon lenses seem like interior dust magnets.

Monocular converters also seem to have fungus.

I had ten Swift 0.965 inch fit eyepieces, erecting prisms and diagonals all with fungus.
I have cleaned three.

I had mold in a brand new 'waterproof' bag for the Skywatcher 90mm Maksutov.
I threw the bag in the rubbish bin.
The scope is fine.

If a binocular case smells funny, it goes in the rubbish bin.

I had fungus in a low price waterproof brand new Chinese binocular.

It also doesn't look like balsam separation in the photo.

Australian forces in WW2 had brand new binoculars completely covered in fungus in 6 weeks from new.
They had to set up mobile units to clean the binoculars all the time.

Sunlight and silica gel help.

Any optics bought from a seaside town in Britain is suspect.

Hope you can clean the surfaces.

Regards,
B.

 

[Binastro]

Further to the above.

I used to use a fine brush to clean camera lenses.
But I realised I flicked the dust off with my finger.
Over time the grease from my finger would build up.
On outer surfaces this shouldn't matter too much as any fungus appearing can be wiped off.

But if the brush is used on an inner surface, fungus feeds on grease, skin particles etc.
It gets minerals from the glass, depending on glass type, or maybe coatings.

It may be that the fine straight or curved lines in photo #3 are from a lens cloth or brush.
In themselves there would be no fungus centrally on a lens surface.
But fungus could take advantage of these lines, sometimes parallel fine lines, which are unusual.

Normally fungus starts at the edge of a lens element often creeping round from the front as moisture gets in.

In photo #3 there may be continuation of the lines from the centre towards the edge, but the condensation doesn't extend that far. So one doesn't know how far the fine lines extend outwards.

But it would probably help if the inner surface was carefully cleaned.

Regards,
B.

 

[yarrellii]

Thank you Binastro, this is most helpful.
I removed the black outer protection on the rim of the EII objective, and I could see there was a metal ring with two small indentantions at opposite positions on the outer part, like if they were at 3 and 9 on a clock. I assume you have to unscrew them, but I'm afraid a special tool is needed in order to do so. Something that is as wide as the lens and with a very thin edge, say like an incredibly wide screwdriver or a pair of special tweezers/pliers of some sort.

 

[Binastro]

I have an EII, but I will leave it alone as the binocular is in fine condition.

It may be that the whole front bell just unscrews from the body with no tools necessary.
Somebody will soon advise I am sure.

If so one must mark carefully the joint so when screwing back it goes to exactly the same position.

There are opticians tools with varying spacing used to unscrew camera lenses etc.
They are I think easily available.

I have for instance unscrewed a Canon 50mm f/1.5 rangefinder lens with fungus on the inner front element and it cleaned up nicely. A nice camera and lens. A Leica copy.

I have unscrewed the bell on Zeiss type binoculars many times, but the position must be marked.

Regards,
B

 

[Binastro]

It may not be advisable to take the objective doublet out as it would be difficult to get in back to the same position, without careful removable marking.
It probably is fitted to best position, although doublets do rotate by themselves over the years.

I have found telescope objectives refitted back to front, producing strange images.
That is why the telescopes end up being sold cheaply.

The Questar had the eyepieces completely wrongly assembled after cleaning.
The telescope could not give an image.
It took about twenty minutes to fix two eyepieces.

Nowadays I don't take many optics apart.

Regards,
B.

 

[henry link]

Yarellii,

I should have mentioned that the thin trim ring might unscrew leaving the threaded objective cell still in place. Just hand twist the whole thing. DO NOT try to remove the slotted retaining ring inside the cell! As Binastro mentioned be sure to make marks so that you can tighten the cell back to the same position.
Sometimes some effort is required to unscrew the cell (just like a pickle jar), but be sure not to use any tool that that would damage the exposed threads.

Henry

 

[Alexis Powell]

Writing from the perspective of someone who spent a solid three years studying the growth of fungal hyphae and developing mutant strains with very strange patterns of growth (a research program to which I may return this year), I say with confidence that those strange patterns are not a result of fungal growth. Hyphae don't grow in looping patterns like that and they avoid overlapping with one another (whereas those lines intersect in many places and show no response to one another).

--AP

 

[Binastro]

Thanks Alexis,

Regards,
B

 

[yarrellii]

Alexis, that's really interesting (an impressive, I'm always impressed by researchers studying those kind of things, sounds absolutely sci-fi to me).

Thank you Binastro and Henry for your suggestions, but after trying to figure out how to do it, I think it's safer for me to acknowledge that this is beyond what I'm capable of a the moment (maybe I can read or try to watch some info about it, but right now I'm afraid that my lack of knowledge may actually cause more harm than good to the poor EII). I thank you anyway for your ideas and suggestions. I'll keep an eye on the EII to see if I spot something wrong. Thanks!

 

[willisoften]

Alexis might know for sure but I believe low intensity uv-a will kill fungal growth. Other frequencies are better but I believe only uv-a will penetrate glass.