altitude induced separation?

[eddie]

hey all,

i seem to have experienced altitude induced separation on two lenses. what gives? it kind of sucks cause the one lens is a nice old globes style lens made by Gasc! gggrrrr!

anyway, i had shipped a lens to a guy in NL. he complained of separation. i got it back an it had separation that it did not have when i shipped it.

the latest was on the globe lens. i have it in my check bag on a flight. i know it did not have the separation when i packed it.

anyone else experience this? i hate to ask is it possible cause it have witnessed it but how about how likely is it?

so far so good. it has only happened twice....so far.

eddie

[David McNiven]

I was a camera repairer until 2000 and I haven't heard of altitude causing balsam faults - but an unpressurised aircraft hold would be equivalent to an increase in the pressure of any bubbles in the balsam layer at ground level - so,... maybe,... possibly.
But if it was a problem wouldn't we have been aware of it since long ago?
Lenses fly all the time and have done so for many years.
I believe the hold of an aircraft gets pretty cold - balsam failures always seemed more common in high summer & the depths of winter. Incipient faults triggered by temperature I expect.

[Jason Greenberg Motamedi]

Eddie, I think David is most likely correct. The cause was probably a relatively rapid change of temperature within the baggage hold. While I have never had problems with lenses on airplanes, I have had a BosScreen delaminate in checked luggage, and it looked exactly like the other screen I killed by leaving the camera outside in (East Coast) winter.

[Drew Wiley]

I've had it happen with extreme day/night temp swings in desert canyons, but only with older-style (non-UV-cure) lens cements.

[eddie]

it happened once and i dismissed as me being crazy ( i am crazy you know?)...then it happened again.

one was a 140 year old lens the other a newer tessare from the 30s or so.

the buyer had some unhappy words fro me about the tessar......i could not figure out what he was talking about till i saw the lens....and of course it was overseas....arrrggg.

thanks for the info so far.

eddie

[GPS]

I was a camera repairer until 2000 and I haven't heard of altitude causing balsam faults - but an unpressurised aircraft hold would be equivalent to an increase in the pressure of any bubbles in the balsam layer at ground level - so,... maybe,... possibly.
But if it was a problem wouldn't we have been aware of it since long ago?
Lenses fly all the time and have done so for many years.
I believe the hold of an aircraft gets pretty cold - balsam failures always seemed more common in high summer & the depths of winter. Incipient faults triggered by temperature I expect.

Forget about the increased pressure in bubbles. Once the balsam is firmly cured the pressure in bubbles doesn't change with outside atmospheric pressure changes.
The outside temperature change, quick as it is in airplanes, is the real danger. The same when you heat the lens quickly.

[Tracy Storer]

I would think a few generous and well sealed layers of bubble wrap would insulate the lens from rapid temp changes....advise buyers to allow the item time to adjust to local conditions before opening as well?

[Jeffrey Sipress]

Never check your fragile gear on airplanes. carry it on. period.

[ic-racer]

I have had experiences with tearing apart junk lenses to try and fix and clean them where I get moisture between the elements, thus showing a separation. My thought has always been that the separation was already there, but with no moisture in there, the separation was essentially invisible. Once moisture gets in there the separation is more clearly seen.
Again, that is just my experience.

[David McNiven]

GPS, if you re-read my post you will agree that I wrote of relative, not absolute pressure.
You do understand that a reduced outside pressure is "equivalent" to increased internal pressure? The reason a sealed balloon expands as it rises?
Canada balsam as used in older lenses is a tree resin and of variable quality, just like wood. Bubble inclusions - sometimes visible, sometimes not - are commonplace. Balsam faults were much rarer when these lenses were new - the layer deteriorates with age.
The slight possibility exists of a reduction in outside pressure causing separation of an already-weakened balsam bond.
This possibility is the reason I didn't dismiss the suggestion but tried instead to offer a more likely explanation.
Premature certainty is just one of the enemies of accurate diagnosis.

[GPS]

David, the balloon expands because it's not a firm object. A bubble in a steel ball would not change its shape, would it? Once the balsam is firmly cured, the outside atmospheric pressure (or the bubble pressure inside it) doesn't change its shape at all.

[David McNiven]

GPS
Hi, I expect many other readers would agree with your commonsense position which I take to be "How could the pressure of tiny bubbles possibly move glass or steel?" Physics disagrees though...
"A bubble in a steel ball." Yes it would and yes it does. Force is applied and expansion occurs. Depending on the size of the "bubble" (ie. big) and therefore the wall-thickness of the ball (ie. thin) it's even measurable with commonly-available instruments. A tiny bubble in a thick-walled steel ball just makes measurement harder.
Does it help to think of a lens couplet as two "firm objects" joined by a rather less-firm layer? That is, after all, the case in point.
Is it the actual reason for the failure of the balsam layer though? Still unlikely!
Cheers,
David.

[Kevin Crisp]

All submarines have crush depths.

[neil poulsen]

All submarines have crush depths.

If a submarine didn't have a crush depth, I suspect it would be heavy enough that it would sink to the bottom under any circumstances.

[neil poulsen]

Does UPS "Ground" actually stay on the ground? Dunno.

[Eric James]

Does UPS "Ground" actually stay on the ground? Dunno.

Not always. For example, if something is sent UPS Ground from Anchorage to Albuquerque it would initially travel by air to a hub and then continue by ground.

[GPS]

GPS
Hi, I expect many other readers would agree with your commonsense position which I take to be "How could the pressure of tiny bubbles possibly move glass or steel?" Physics disagrees though...
"A bubble in a steel ball." Yes it would and yes it does. Force is applied and expansion occurs. Depending on the size of the "bubble" (ie. big) and therefore the wall-thickness of the ball (ie. thin) it's even measurable with commonly-available instruments. A tiny bubble in a thick-walled steel ball just makes measurement harder.
Does it help to think of a lens couplet as two "firm objects" joined by a rather less-firm layer? That is, after all, the case in point.
Is it the actual reason for the failure of the balsam layer though? Still unlikely!
Cheers,
David.

David, trying to split hairs? The tiny bubble in a steel ball suddenly became big air space in a thin steel case with measurable deformation? To prove what? That the described balsam deformation is "still unlikely"? How about a deformation threshold? How about elastic deformation? How about infinitesimal deformation or, as suggested, crushed submarines - try to split it even more.To find the reasons for "still unlikely", of course...;) But doing so, don't forget the common sense - you cannot have a cake and eat it.
Temperature changes have far more significant effect on balsamed lenses that any atmospheric changes can have.
Unless you want to study the deformation in optical glass with air bubbles enclosed in it when exposed to atmospheric changes. Still unlikely but good enough to write about, no? :)

[bobwysiwyg]

Aren't virtually all commercial aircraft luggage compartments pressurized to the same extent as the passenger compartment? I believe that is approx. the equivalent of 8,000 ft.

[David McNiven]

GPS.
I'm always happy to respond to a well-reasoned argument...just as soon as one is presented.
David.

[GPS]

Aren't virtually all commercial aircraft luggage compartments pressurized to the same extent as the passenger compartment? I believe that is approx. the equivalent of 8,000 ft.

I don't think so. Don't ask me how I know (well, I left a can of beer in my checked baggage once - at my arrival the can was empty and - to my greatest surprise, the baggage was completely dry too, just stained...:) )

[Thebes]

This seems plausible to me. I live at about 7000 feet and we have all kinds of altitude quirks. For example, items packaged with those inflated bags are heavily pressurized when they arrive, often a few of the bags pop and its damaged packaging. I doubt that a lens would fail if it wouldn't have eventually failed, but I'm sure it would speed things up to pressurize those bubbles relative to the atmosphere.

UPS ground- if you shipped it hazmat, a pain to be sure and prolly want to include a couple ounces of metol or something make it legit... then it would have to stay on the ground wouldn't it? Of course your lens might still go through mountain passes that prove the final straw.

[Kevin Crisp]

Aren't Tessars air spaced?

[Sal Santamaura]

I suspect the rather intense high-frequency vibration experienced in a jet transport may have something to do with this. :)

[Paul Fitzgerald]

I think it has much more to do with the large, rapid temperature changes (take-off and landing) than with pressure differences.

Cemented lens would have at least 2 different types of glass, different expansion ratios, plus a third - the balsam.

Most cemented doublets have a rather thick negative element with a positive that has razor thin edges == MASSIVE expansion difference. Triplets would be worse.

Wrap the lens with temperature in mind if it's shipping by air, should solve the problem.

[GPS]

Aren't Tessars air spaced?

Is the OP's globe lens a Tessar?
Air spaced lenses in LF objectives don't suffer from altitude sickness either - they are separated by metal spacers firm enough even in high altitudes...:)

[Bernard Kaye]

Put a sound Rollei 35, a well made camera, with Tessar or Sonnar lens in its case on the jet's floor between your feet for an 8-12 hour flight and be prepared to have to tighten several screws inside that have worked loose from vibration. Larry Work, formerly a great camera technician in Dallas, showed this to me on my gear and others. I did jet a lot at that time. I think that this vibration will eventually get to loosen much.
Bernie Kaye

[Drew Wiley]

Altitude certainly makes a difference with anything "sealed", including farts. Everyone who backpacks knows how a bag of potato chips will almost explode at
high altitude from internal pressure. But since I carry lenses from low to high all the time, and have only had an issue under dramatic temperature swings, like an
80-degree difference from day to night, I don't think that modern lenses are very susceptible to simple pressure damage. After all, lenses on reconaissance aircraft change pressure far more suddenly than lenses in our kits, and they seem to hold up fine. Another kind of problem might be inherent in "hybrid" lenses which mix glass
and plastic elements, but these kinds of lenses are generally very small, hence
have relatively little overall dimensional change, and to my knowledge are not used
for large format work at all.

[GPS]

Besides, lenses are not airtight, especially the barrel lenses (the OP's Globe lens?)are not. Air seeps in minute amount through their threaded rings and barrels. That's how fungus is often introduced in between lens elements - the constant atmospheric pressure changes pump the more or less humid air in and out with fungus spores present in it or on the barrel's surface.

[domaz]

In some areas of the world the temperature drops 3 degrees for every 1000 ft. So going from sea level to 14000 ft you could go from 50F to 8F in less than an hour. You are unlikely to encounter that kind of temperature change in nature. Is an old lens designed for that? Doubtful.

[Steven Tribe]

I have separated quite a lot balsamed lens and always found them astonishly well stuck together even after more than a hundred years. Even the balsam in the middle is still sticky. I am convinced damage in flight is most likely a consequence of temperature change or even, co-incidence. Pressure effects (any holes in the balsam will vent through channels that have already been formed as the separation started) or vibration (there really isn't much anymore!) are not causes.

[Don Dudenbostel]

I would suspect rapid temperature changes to be more of a problem than pressure but I'm reluctant to believe even temperatre changes are the problem. I'm a pilot and have regularly carried my equipemnt in an unpressurized cabin above 13,000ft with absolutely no problem. This includes older film gear as well as newer digital equipment. Cabin temp has remained fairly constant but pressure has decreased dramatically. Just out of college I worked part time for an areial research company flying in an unpressurized cabin up to ~13,000 feet with our 9"x9" Zeiss mapping camera and quad mounted Hasselblads in open ports in the floor of the aircrtaft. The temp drops ~2.5 degrees F / 1000 ft and in the winter when the surface temp is +25f the temp at altitude is sub zero F. Cameras were exposed to these pressures and temps for hours at a time. I have flown and shot aerial assignements opening and closing the window shooting out of the plane when the air temp was -30f and had no problems other than freezing my a$$ off. Also in the case of Fedex and UPS the aircraft are pressurized and heated in the cargo area with the exception of some of the small contract carriers flying small aircraft. Temperature and pressure sensitive items are frequently carried by both.

[domaz]

For a second hypothesis- I remeber reading a thread on APUG where this happened to someone selling an old lens. He suspected the guy heated the lens in the oven to induce seperation because he had buyers remorse. Seems kind far-fetched to me but you never know I suppose.

[eddie]

13 months later.......

well.....looks like number three to me! i have had another issue with separation again. the lens developed greater separation since leaving my hands.

i have not received it back yet but i know and trust the buyer so i am sure it is as he says it is. i will not be able to handle the lens until i return home in a couple of months but it has happened again! when the lens left my hands it had very little separation....now it has more.....damn!

eddie

[William Whitaker]

Several years ago I purchased a lens which was advertised as having no separation. When it arrived, it had an annulus of separation completely around the edge. Fortunately the seller took it back without any grief. (Was it you?) Anyway, I seem to recall that it was a Protar VII (which I understand are prone to separation). The seller had been emphatic that there was no separation when it left his hands. However, it clearly did when it arrived. I surmised at the time that it must have been due to a combination of old glass, early balsam and conditions in-transit which all contributed to its demise. A second episode presented itself when I received a 240 Rodagon with the same issue. I've seen several Rodagons with separation, but again the seller assured me that it had not been there prior to shipping and I didn't really have any cause to doubt him.

Whether it's cabin pressure, temperature change or vibration, the one thing that seems to be a constant is that the victims are all elderly. (Well, maybe the Rodagon isn't, but it's one which seems to suffer from a congenital defect. Whatever balsam Rodenstock used was not top-shelf.) The only thing we can do is to try to minimize the contributing factors. So I offer the following suggestions, fwiw.

You said your globe lens was in a checked bag. I would not trust a valuable lens to baggage handlers regardless of its vintage. I'd find a way to put it in a carry-on bag. When shipping, double-box with adequate packing so that the lens will survive a 3-foot drop off a conveyor belt. Insure for the full amount. And finally, ship it via a premium service, overnight if necessary. That way its exposure to the shipping environment is minimized. I theorize, too, that if something is shipped overnight, it has a greater perceived value and is possibly going to get better treatment. Not always true and hard to prove if it is. But when all you can do is to try to stack the deck in your favor, why not?

I don't mean to sound like I'm lecturing. But maybe some Ebay seller will read this someday and pack the lens I just bought from him so that it will survive.

[eddie]

Great ideas will.

FWIW I follow all your suggestions......except the checked bag one..... The last one was shipped by a post office.

Cheers