I am becoming curious about this, as I never disassembled a lens myself.
Both you and P�l (who actually saw the material) say that the inner barrel
is of steel so I believe it. But if the outer casing is aluminum, there
could be a problem. If you found definitively what the material of the
inner barrel is, please let me know. For now, I assume it's steel (although
it's heavier and harder to machine). It was actually Mr.Hirakawa, the
designer of the lens, who said that the lens was made of aluminum. I did
not think he was distinguishing the outer barrel from the inner one.
Is the metal barrel usually of steel or light metal?
I am not certain what light metal was referring to. But I am certain the inner barrels aren't aluminum alloy. The reason is simply. When you assemble different parts together and tight the screws, the steel threads would be able to sustain much more stress and drag than aluminum alloy. This is one reason that very fine thread screws won't be used on aluminum alloy. For example, P series bodies have aluminum alloy structure. The mounting screws are super tight the very first time they were tightened because the screw holes are threadless (such word exist?)). But as soon as you loosen those screws, there is no way you can tighted them as tight as before. If you do, the threads of the aluminum alloy would be stripped. The only solution is to apply screwlock on them. Plastic has the same problem, only worse.
regards, Alan Chan
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