What is this? Should I run like hell?

[rokphish]

The rest of the lens looks pristine, body and glasses.

[Chucktin]

Could be someone tried to clean the back element with a caustic (glass cleaner with an additive?) and that etched the metal. You may never know how much that effected the rest of the lens without a tear down.

 

Sent from my Pixel XL using Tapatalk

[milandro]

It looks like that you can take that metal element out by unscrewing 3 screws. I don’t think there is anything more complicated than that!

 

It should then be easy to clean although the pattern looks like it is almost something intentional ( i can see a smudge where you probably have tried to clean the metal retainer) but it is impossible that it would have been purposely done when new.

 

Is this a Minolta 135mm MD f2.8 or thereabouts? They are not special lenses but should be good and frankly speaking given their relatively small value there is nothing wrong in attempting to clean it, you won’t be losing much even if you were to damage the lens.

 

Other than that, this is not a type of fungus which could infect your camera and other lenses and it would be harmless, I think.

 

If the metal is, as I think, aluminum, it has to be a reaction to some agent producing aluminum oxide crystals.

 

Remove them and then apply a coat of black spray mat paint.

 

http://www.howtocleanthings.com/surfaces/how-to-clean-aluminum/

Edited June 16, 2017 by milandro

[lleo]

That seems to be only a metal cover. Remove it and check it. Probably it's everything else ok. There are some black paints for the metal parts of the lenses.

[mdm]

Is this a Minolta 135mm MD f2.8 or thereabouts? They are not special lenses but should be good and frankly speaking given their relatively small value there is nothing wrong in attempting to clean it, you won’t be losing much even if you were to damage the lens.

 

 

Sorry for off topic but I need an advice.

 

Milandro, I'm pretty sure you have a big deal of experience with old Minolta lenses, so could you please suggest me what may I add to my recently purchased Minolta X-700 equipped with 50mm 1.4. I'd like to add some lens in wide and tele department. I've heard it's better to avoid MD III series and get older Rokkor ones. What can you say?

[addicted2light]

Sorry for off topic but I need an advice.

 

Milandro, I'm pretty sure you have a big deal of experience with old Minolta lenses, so could you please suggest me what may I add to my recently purchased Minolta X-700 equipped with 50mm 1.4. I'd like to add some lens in wide and tele department. I've heard it's better to avoid MD III series and get older Rokkor ones. What can you say?

 

 

You might find this helpful:

 

http://artaphot.ch/minolta-sr/objektiv-vergleiche

 

This guy tested old Minolta lenses on Sony full frame bodies and against modern glass like the latest A and E mount offering.

 

It is mostly in German (use Google Translate), but often the images really speak for themselves.

 

On a side note, I like quite a bit my Minolta MC 24/2.8 (old version, not the new one with the 49mm filter size) and the 105/2.5 MD (latest version).

[mdm]

You might find this helpful:

 

 

Thank you. I'll check it.

105/2.5  - never saw this facal lenght.

[milandro]

@mdm 

 

the Minolta lenses are all outstanding and actually series III are very compact 

 

read about them here

 

http://www.rokkorfiles.com/Lens%20History.html

[addicted2light]

Thank you. I'll check it.

105/2.5  - never saw this facal lenght.

Sorry I meant 100/2.5!

[pranfeuri]

Could be someone tried to clean the back element with a caustic (glass cleaner with an additive?) and that etched the metal. You may never know how much that effected the rest of the lens without a tear down.

 

Sent from my Pixel XL using Tapatalk

I have an 135mm Minolta lens that has just the same problem and it's never been cleaned with anything.

Edited July 24, 2017 by pranfeuri

[milandro]

I am sure that it can easily, as described, be removed and cleaned 

Edited July 24, 2017 by milandro

[Aswald]

The rest of the lens looks pristine, body and glasses.

 

Just remove the screws, take the cover out and wash it with water and a good toothbrush. Use a good multipurpose cleaning agent, rinse clean, dry (under the sun for a good dose of uv) and replace. Chances are It won't come back again.

Edited July 25, 2017 by Aswald

[rokphish]

Thank you for the replies.

I bought the lens and returned it because some problems with the glass.