Cold weather problems with Zeiss 8x32 SFL (4 Viewers)

[Jon.Bryant]

I have just been birdwatching in Inner Mongolia where the morning temperature was sometimes below -40 degrees C.

I noticed that when my binoculars got very cold, they misted up on the centre part of the objective lens, on the internal surface. The misting quickly cleared with a slight bit of warmth - even holding the bins in my mittens started clearing the lens.

Since I have relocated to the tropics, I have had no problems.

I have contact Zeiss who have asked me to send them to their repair centre for examination, but I was wondering is the misting is ‘normal’ in extreme cold. Has anybody had similar experience? Interesting that my wife’s 8x42 were not effected the same, but I suppose the surface to volume ratio of the smaller bins is greater, so perhaps the internal environment of my bins cooled more.

 

[james holdsworth]

My 10x32 SF have done the same when temps reached near -20, apparently a tiny bit of moisture not fully purged between the objective and the glass sealing plate. It’s gone away without consequence although I’m not particularly happy with the implication.

Edit - wondering if, in the case of the SF, the outer glass plate is considerably thinner than a proper objective element, and (as a result) reacts more to sudden temperature drops, as none of my other bins have shown similar behaviour.

 

[NDhunter]

I suppose any optic is not put together in a perfectly very low humidity environment. The reports seem normal
to me. Gas purging may not be the full answer either, as it does not last long.
Jerry

 

[Jon.Bryant]

Gas purging may not be the full answer either, as it does not last long

Can you elaborate. Aren’t the binoculars purged and filled with nitrogen? If they are completely sealed, doesn’t this last forever?

 

[Jon.Bryant]

wondering if, in the case of the SF, the outer glass plate is considerably thinner than a proper objective element

Can you advise what you mean. The SF are a premium binocular, so why thinner lens than a ‘proper objective’?

 

[james holdsworth]

As I understand it, the SF focuses by moving elements forward and back on a carriage, and the binocular is sealed with a coated optical glass plate.

 

[Maljunulo]

As I understand it, the SF focuses by moving elements forward and back on a carriage, and the binocular is sealed with a coated optical glass plate.

This is also my understanding.

An interesting approach to the focusing problem.

 

[Canip]

Can you elaborate. Aren’t the binoculars purged and filled with nitrogen? If they are completely sealed, doesn’t this last forever?

Yes, they are purged and sealed at the factory, but the nitrogen filling doesn‘t last forever, of course (nobody ever claimed binoculars were completely airtight, they are supposed to be waterproof). Some binos have special valves to enable easy repurging. So far, nobody has been able to tell me how long the nitrogen content is supposed to last, this probably depends on a number of factors.

 

[NatureLover123]

According to spec the SFL 8x30 claim to be intended to work until -20 degrees not -40.
And the SF 8x32 until -30

 

[Swedpat]

SFL 8x32 is a typo. There is SFL 8x30 and SF 8x32. Which model is this about?

 

[Jon.Bryant]

And the SF 8x32 until -30

Thanks for this. I looked for operating temperature in the online spec but could not find it (or missed it in error).

If the fogging up is normal outside spec, I am therefore surprised Zeiss have said they will examine the bins - unless there is something more onerous to using them outside the operating temperature. As I say, they seem fine now.

 

[Jon.Bryant]

Which model is this about

Sorry, I thought I had mentioned the model, but it seems not - Victory SF 8x32. Not sure if they did this size in the mark I grey armour, and mine are the mark Ii black armour (bought last autumn).

 

[garymh]

Nitrogen molecules will leak out of a binocular over time due to their size. It is probably a good idea to have a nitrogen purged binocular serviced and re-purged every few years.

Some manufacturers (I think Minox was one) used Argon which has larger molecules than Nitrogen and does not leak out so quickly.

 

[Tringa45]

Some manufacturers (I think Minox was one) used Argon which has larger molecules than Nitrogen and does not leak out so quickly.

Argon will probably diffuse out quicker than Nitrogen. See: Partial pressure - Wikipedia

John

 

[NatureLover123]

According to spec the SFL 8x30 claim to be intended to work until -20 degrees not -40.
And the SF 8x32 until -30

I meant degrees celsius not degrees fahrenheit.
Yes I took it from the public Zeiss website.

Do you think that nitrogen leaks out so quickly? 😯 I hope not. He bought his pair last autumn.

This would be a bad product design of a major feature: You would need a refill, every now and then.

 

[Canip]

Some manufacturers (I think Minox was one) used Argon which has larger molecules than Nitrogen and does not leak out so quickly.

Looking at things like partial pressure difference, nitrogen is the better choice than argon (see post # 14 above by Tringa45, and Holger Merlitz, The Binocular Handbook, Springer Nature, 1st ed 2023, p. 97).

 

[MiddleRiver]

-40C (first post above) is extremely cold. In fact it's -40F (weirdly the temp where numerical value for C and F are the same). Not saying it's not an issue but I'm amazed the bins work at all at those temps!

 

[Binastro]

The Komz binoculars worked fine at minus 34C.
They are marked O.K. at minus 40C.

Old Minolta, Canon and Nikon lenses worked fine at minus 37C.

My telescopes were fine at minus 30C.

The Nikon FM2N apparently works at minus 50C.

Leica cameras can be winterised.

Different fuel is used for cars and trucks at low temperatures.

Tyres can break below minus 40.

Some top movie lenses are temperature compensated to work at minus 40C or plus 40C without changing characteristics.

Kodak film broke hopelessly at minus 34C.
Konica film was fine.
Some movie films break at cold temperatures.
The plastic camera strap and case were so brittle at minus 34C they would have shattered if knocked.
Leather seems fine.

In Sweden cars are plugged in to preheat at a set time in car parking areas.

My Fisheye converter cracked in half at minus 30C. I think a Spiratone make.

My friend worked in a coffee freezing place I think at minus 40.
Freezers are usually only minus 18C.

Regards,
B.

 

[Dennis Mau]

Why are binoculars filled with Nitrogen? - Optics Trade Blog

Introduction Binoculars are designed to be used for bird-watching, camping, and other outdoor activities but a little careless attitude can result in dust, moisture, and spores in the lens compartment. Optical devices are always prone to moisture contamination because as soon as they are exposed...

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