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Minolta MD ROKKOR 1.4 50MM Fungus
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PostPosted: Sun Sep 18, 2016 8:17 am    Post subject: Minolta MD ROKKOR 1.4 50MM Fungus Reply with quote

Hi, I have just bought this lens knowing that it had some degree of fungus, however the fungus is inside the front element group, my question is has anyone opened this sealed group to clean inside, if so please advise method.

These pics show the encapsulated front element design, in the second photo there are 6 x pins that look like they are small rivets.



Last edited by tileman on Sun Sep 18, 2016 8:35 am; edited 1 time in total


PostPosted: Sun Sep 18, 2016 8:33 am    Post subject: Photos Reply with quote

The photos displayed OK in the Post preview, but not when I had submitted the Post, I did a reply asking what was wrong and the photos were there, I deleted the reply and they were gone again.
Help please.


PostPosted: Sun Sep 18, 2016 8:58 am    Post subject: Re: Photos Reply with quote

tileman wrote:
The photos displayed OK in the Post preview, but not when I had submitted the Post, I did a reply asking what was wrong and the photos were there, I deleted the reply and they were gone again.
Help please.

Default forum behaviour designed to fight spam.

As for the fungus problem, I don't think it's worth it or even possible to open this unit. Or maybe you can open it, but then you won't be able to put it back together without specialist tools. I have a 50/2.0 with the same problem (similar construction) and gave up trying to fix it...


PostPosted: Sun Sep 18, 2016 11:00 am    Post subject: Reply with quote

Cheers Miran, you are probably correct, I don't think the fungus is bad enough to affect images, but I will know when the adaptor comes.


PostPosted: Thu Sep 22, 2016 5:36 am    Post subject: Anyone out there !!!!! Reply with quote

Surely someone has stripped one of these lens groups on this very popular lens that is prone to fungus.


PostPosted: Fri Sep 23, 2016 2:12 pm    Post subject: Reply with quote

May be someone did, but the reality is that people who are capable of doing quality work on lenses also know what to stay away from.


PostPosted: Fri Sep 23, 2016 5:00 pm    Post subject: Reply with quote

Those six rivets would probably be spun rather than hammered / pressed to secure them, and more than likely all six would be spun together in a machine with six spinning heads to ensure they pull down evenly. And there's less likelihood of operator error in the manufacturing process. I worked in a factory for a short time where they made time switches, and the tiny motor casings were riveted in this manner to ensure they went together evenly.
I really wouldn't take it apart unless you have the right tools and skills to put it back together. Although modern industrial adhesives might be good enough to do away with the rivets?


PostPosted: Mon Sep 26, 2016 9:39 am    Post subject: Reply with quote

Lloydy wrote:
Those six rivets would probably be spun rather than hammered / pressed to secure them, and more than likely all six would be spun together in a machine with six spinning heads to ensure they pull down evenly. And there's less likelihood of operator error in the manufacturing process. I worked in a factory for a short time where they made time switches, and the tiny motor casings were riveted in this manner to ensure they went together evenly.
I really wouldn't take it apart unless you have the right tools and skills to put it back together. Although modern industrial adhesives might be good enough to do away with the rivets?


Cheers Lloydy, the fungus isn't too bad and certainly doesn't affect the images, not that I can see anyway, I just like my kit to be in top condition.


PostPosted: Mon Sep 26, 2016 10:29 am    Post subject: Reply with quote

Lloydy wrote:
Those six rivets would probably be spun rather than hammered / pressed to secure them, and more than likely all six would be spun together in a machine with six spinning heads to ensure they pull down evenly. And there's less likelihood of operator error in the manufacturing process. I worked in a factory for a short time where they made time switches, and the tiny motor casings were riveted in this manner to ensure they went together evenly.
I really wouldn't take it apart unless you have the right tools and skills to put it back together. Although modern industrial adhesives might be good enough to do away with the rivets?


Aren't such units laser heat-welded? I have seen it done with knives scales, after such welding I was told they are permanently attached. I have two groups like these as well, I tried to puncture one at a lens junction point I made two holes, pouring inside cleaning liquid with a needle.

Alas I ended up scratching one lens due to poor handling of the needle, such groups stupid assembly ends up making me nervous so I didn't act with the usual prudence.

It surely is a cost saving measure but a repair implies substitution.