Everything Leaks (Page 5): I believe dual pane windows have argon gas between the panes. I've wondered in the past how long that gas actually stays in there.

10MPlayer Loc: California

I believe dual pane windows have argon gas between the panes. I've wondered in the past how long that gas actually stays in there.

LFingar Loc: Claverack, NY

Doyle Thomas wrote:

I recently took a class on vacuum technology. One ... (show quote)

Which 'best lenses' use argon? I can find no reference to anything by Canon, Nikon, Sigma and so forth using argon. There may be some specialty lenses that use it but I doubt that it is common. The lens teardowns I have seen, such as Canon's EF 100-400 L II, don't mention it.

TriX Loc: Raleigh, NC

LFingar wrote:

Which 'best lenses' use argon? I can find no reference to anything by Canon, Nikon, Sigma and so forth using argon. There may be some specialty lenses that use it but I doubt that it is common. The lens teardowns I have seen, such as Canon's EF 100-400 L II, don't mention it.

I agree. I don’t see how you could seal anything other than a fixed focus prime.

User ID

TriX wrote:

I agree. I don’t see how you could seal anything other than a fixed focus prime.

No reason for it to be fixed focus. Also a complex (zoom etc) lens could still be gas pressurized at each discrete, fixed, cluster of elements.

I tend to agree with others who doubt that the lenses which we generally encounter, with prices well below 5 figures, would be gas pressurized.

TriX Loc: Raleigh, NC

User ID wrote:

No reason for it to be fixed focus. Also a complex (zoom etc) lens could still be gas pressurized at each discrete, fixed, cluster of elements.

I tend to agree with others who doubt that the lenses which we generally encounter, with prices well below 5 figures, would be gas pressurized.

Yes, I guess maybe you could pressurize between groups - I was thinking about the difficulty of sealing a rotating focus barrel or the sliding barrel for those zooms that extend in length when zooming.

I was able to find one moderately priced nitrogen filled lens with a quick Google search: https://asia.olympus-imaging.com/product/compact/accessory/conversion_lens/index.html

JD750 Loc: SoCal

Re link below see: Final Assembly, page 32 and following pages.

https://dspace.mit.edu/bitstream/handle/1721.1/69779/776202013-MIT.pdf;sequence=2

Also see: Assembly main line.
https://www.tamron-usa.com/_data/lens_catalogues/Production_Process_Tamron_Lens.pdf

I did not see anything about inert gas pressurization.

Doyle Thomas Loc: Vancouver Washington ~ USA

LFingar wrote:

Which 'best lenses' use argon? I can find no reference to anything by Canon, Nikon, Sigma and so forth using argon. There may be some specialty lenses that use it but I doubt that it is common. The lens teardowns I have seen, such as Canon's EF 100-400 L II, don't mention it.

there are also liquid filled lenses used in military satellites since the 1960's

Doyle Thomas Loc: Vancouver Washington ~ USA

Dino92G wrote:

That is a great question! One comment though on y... (show quote)

then why do u need Helium Leak Detectors? lol

LFingar Loc: Claverack, NY

Doyle Thomas wrote:

there are also liquid filled lenses used in military satellites since the 1960's

The CIA's Corona satellites, which were operational from 1960 to 1972, used a number of technologies that were previously unheard of. Liquid or gas filled lenses are rare in the consumer market just the same. A bigger benefit to the average photographer is that the Corona project demonstrated the need for something better then film for spy satellites. The CIA financed much of Kodak's research into digital. The rest is history. Too bad that Kodak was smart enough to create digital photography but not smart enough to market it properly.

TriX Loc: Raleigh, NC

LFingar wrote:

The CIA's Corona satellites, which were operationa... (show quote)

Interesting reading (wiki) on the Corona program. The NRO was a customer of mine for many years, and I am familiar with the later KH (Keyhole) satellites and technology, but I didn’t know the history of the film based birds. Thanks for the insight.