Cause of scratches on objective

[Traleah]

Looking on eBay:

https://www.ebay.com/itm/Olympus-SPlan- ... SwrnNfUVDe

What would cause these scratches?

Maybe this question belongs in the beginner corner. If so, maybe someone can move it there. Thank you.

[BramHuntingNematodes]

When being turned the case acquires minute grooves, exposure to chemicals or water causes the chrome to peel off like that

[Traleah]

Thanks Bram. I looked at one other and it looked like the ring around the lens was bent.

https://www.ebay.com/itm/Olympus-DPlan- ... SwoJJfQxQQ

Is this normal condition for most used objectives? If so, are they easily cleaned? I’m just trying to educate myself on what’s normal/good vs mediocre/avoid.

[BramHuntingNematodes]

there is a common fault where a high power objective that is not well parfocal with the lower powered ones crashes into the sample as it's being spun on the turret. I have a lens that very clearly has a significant bend to the front of the case from this, but the optics seem miraculously unaffected. I think only a trial could determine if anything has been knocked out of alignment.

[Element 56]

Some objectives take a lot of abuse! I have an Olympus D plan 40x that got an acid bath and although I haven't opened it up to verify I think it actually ate through in some places. Makes you wonder if whatever it was exposed to is still eating away at the brass.

Something to think about when buying used equipment is what they may have been exposed to in the past. I always assume it's something I don't want to touch or breath. I work in a fume hood and carefully clean and disinfect every thing I buy no matter how good it looks. All surplus coming out of hospitals and research facilities is supposed to go through a disinfection process but I can tell you from personal experience that doesn't always happen.

Kirby

[apochronaut]

The ebay objective featured in the post was used in a nosepiece that was not completed with parfocal objectives. Probably someone had a mix of 45mm parfocal and shorter parfical objectives and that 100X Olympus was being driven into parts of the slide carrier by one or more klutzs repeatedly. The metallurgy in Japanese microscopes from that era was also shit. They were using melted down Isuzu Bellets and still had a stockpile of Battleship scrap. The brass was intolerably soft( probably as much lead as zinc in it) and it doesn't take that much of a whack to make those kinds of marks.