What could this lens damage be?

The cargo bay cannot have a different air pressure than the passenger part:
-) this would need a stronger floor
-) strain the fuselage differently between upper and lower
-) exclude animals from being transported in the bay

The air pressure in an airliner should not exceed an analog height of about 2500m . Thus you could not go onto a mediocre mountain with such lens (unless it got a slight gas leakage, enough for a slow climb by foot).

I meant analogous

Yes a temperature difference between cemented elements puts mechanical strain on the couple.
And this only comes into existance at rapid change of ambient temperature (We discussed this above on practical feasibility,.)

Different air pressure inside and outside the lens also puts mechanical stress on respective elements.
The change being fast or slow will have same effect on the cemented elements. Unless being very slow (possible creep within the cement).
But for not absolute airtight, but slightly leaking lenses the speed of change in ambient pressure may be of effect whether a differential pressure betweeen inside and outside comes into existance at all. Here we got an analogy to effect of the change in ambient temperature effect above.

Both, for temperature and pressure we did so far not even take into account the material of th barrel. Think of aluminium, a far better heat conductor than glass, which can bring heat energy into the lens innards. Or plastic, which might deform under presure and thus lessen the strain on lens elements.


In post #16 I argued that low air pressure can have no effect on a cemented lens. I then was only referring to the lamination as such, as with a unmounted doublet.

Nodda Duma said:

As a lens designer, I’m trying to provide insight into the cause of lens separation in older optics. That insight — like any insight provided by knowledge and experience — helps lead to practical solutions.

Education, not ego, is at play here.

Click to expand...

Really? Hmmm, could have fooled me...

You'd really have to have some thin skin to take umbrage at what I wrote.

I was just suggesting you protect your lens when you ship it or you might risk it separating regardless of what causes that problem.

Sheesh.

Kino said:

Really? Hmmm, could have fooled me...

You'd really have to have some thin skin to take umbrage at what I wrote.

I was just suggesting you protect your lens when you ship it or you might risk it separating regardless of what causes that problem.

Sheesh.

Click to expand...

I think that Nodda Dumma was disagreeing with others about causation when he replied to your practical suggestion about prevention.