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Unfungusing a Minolta MD 50mm 1.7
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PostPosted: Sun Mar 11, 2012 1:31 am    Post subject: Unfungusing a Minolta MD 50mm 1.7 Reply with quote

After watching the thread from Ian (http://forum.mflenses.com/viewtopic.php?p=1214663#1214663) where he shows the sharpness of this lens, I was impelled to try mine.

Unfortunately the lens was stocked some 10 years and developed fungus.
This is the way I've been able of cleaning them.

There were marks on both sides of the lens.
The top element showed something that I'm not sure were fungus. It might well be some nesting from some small insect:






On the bottom side it was a little different, infestation in a couple of spots (difficult to see in the picture) with spiderweb like shape:



To access the top block, the first step is to unscrew the label plate with a rubber tool:



Then remove the three screws that hold the filter thread holder:



Then remove the filter thread holder, and remove the three screws that keep the lens block in place:



Once the block freed, cleaning is done with hands cream for half an hour, washing and drying and setting it in place again:



The bottom lens block is easy to remove: just unscrew these three screws and you are done:



Just remove the baffle on top and pick the block with a suction cup:



The cleaning process is the same: hand cream for 20-30', careful washing and drying and setup in the reverse sense.

Then you have a clean, useable lens:



Hope this will be useful for someone else.

Regards.
Jes.


PostPosted: Sun Mar 11, 2012 1:42 am    Post subject: Reply with quote

Why the hand cream, Jes?


PostPosted: Sun Mar 11, 2012 6:49 am    Post subject: Reply with quote

Many thanks Jes!


PostPosted: Sun Mar 11, 2012 10:03 am    Post subject: Reply with quote

Orio wrote:
Why the hand cream, Jes?


For some reason, it removes fungus far better than almost anything else without harming coatings plus it acts as a lubricant while cleaning the element thus helping to avoid scratches. It's also very easily available. Only thing it can't undo is if the fungus has etched the glass.

I've used it myself to clean elements that IPA etc wouldn't look at. I then wash it off with lukewarm water and carefully dry the element.

It really works.


PostPosted: Sun Mar 11, 2012 11:22 am    Post subject: Reply with quote

Orio wrote:
Why the hand cream, Jes?


It's wonderful to remove some tipe of fungus. You apply the cream, let it dry for some half an hour, wash carefully with a soft soap cream and the fungus disappear!.

I use this thechnique since long. It's very useful, although there are some fungus that are resistant, but in 90% of the cases have proven useful.

Do you remember my post on cleaning a Samyang 500mm mirror?:

http://forum.mflenses.com/fixing-a-samyang-500mm-f8-mirror-lens-with-plenty-of-fungus-t40526,highlight,%2Bsamyang+%2B500mm.html

This was one of the most successful cases with fungus and hands cream, it fully removed the fungus and they haven't appeared anymore since then.

Regards.
Jes.


PostPosted: Sun Mar 11, 2012 11:24 am    Post subject: Reply with quote

bob955i wrote:
Orio wrote:
Why the hand cream, Jes?


For some reason, it removes fungus far better than almost anything else without harming coatings plus it acts as a lubricant while cleaning the element thus helping to avoid scratches. It's also very easily available. Only thing it can't undo is if the fungus has etched the glass.

I've used it myself to clean elements that IPA etc wouldn't look at. I then wash it off with lukewarm water and carefully dry the element.

It really works.


+1 !!

Smile


PostPosted: Sun Mar 11, 2012 12:02 pm    Post subject: Reply with quote

Jesito wrote:
Orio wrote:
Why the hand cream, Jes?


It's wonderful to remove some tipe of fungus. You apply the cream, let it dry for some half an hour, wash carefully with a soft soap cream and the fungus disappear!.

I use this thechnique since long. It's very useful, although there are some fungus that are resistant, but in 90% of the cases have proven useful.

Do you remember my post on cleaning a Samyang 500mm mirror?:

http://forum.mflenses.com/fixing-a-samyang-500mm-f8-mirror-lens-with-plenty-of-fungus-t40526,highlight,%2Bsamyang+%2B500mm.html

This was one of the most successful cases with fungus and hands cream, it fully removed the fungus and they haven't appeared anymore since then.

Regards.
Jes.


+1 ... Up to now, all the lenses with fungus issues i have cured, have been successfully cleaned with cold cream ...
No dangerous chemicals, like isopropyl alcohol or ammonia, and harmless if you spread it with your fingers instead of using a q-tip ...

Congrats for the successful cleaning ...


PostPosted: Tue Apr 03, 2012 10:40 am    Post subject: Reply with quote

Totally agree,


I've cleaned quite a lot of lenses with fungi and amonia and isopropanol didnt have any effect on them but cold cream after 10 minutes did the job and left the lens looking great.

Even once it helped to clean a rear element with haze from a vivitar zoom i fixed, not completely but it reduced the haze A LOT.


PostPosted: Sat Apr 21, 2012 7:28 am    Post subject: Reply with quote

sorry

what is "hand cream"

something to wash the hands as a soap ?
or is it a cream to protect the hands when weather is cold ?
thank you


PostPosted: Sun Apr 22, 2012 8:47 am    Post subject: Reply with quote

Nelson wrote:
sorry

what is "hand cream"

something to wash the hands as a soap ?
or is it a cream to protect the hands when weather is cold ?
thank you


Is the oily cream women use to use, like Ponds, etc.
Extend over the lens and let it for some half an hour, then carefully wash with a soft liquid soap and warm water, dry and most times (depends of the fungus kind), lens come out clean.


http://forum.mflenses.com/fixing-a-samyang-500mm-f8-mirror-lens-with-plenty-of-fungus-t40526,highlight,%2Bsamyang.html


Good luck!

Jes.


PostPosted: Sun Apr 22, 2012 2:21 pm    Post subject: Reply with quote

Thanks for this info Jes, I have a couple of lenses that have fungus that ISO Alcohol wouldn't remove, I shall try the cream!


PostPosted: Sun Apr 22, 2012 2:56 pm    Post subject: Reply with quote

iangreenhalgh1 wrote:
Thanks for this info Jes, I have a couple of lenses that have fungus that ISO Alcohol wouldn't remove, I shall try the cream!


it works well for many types of fungus, but some are not cleared (the etched ones).

jes.


PostPosted: Sat Apr 20, 2013 8:50 pm    Post subject: Reply with quote

Is there a way to open lens block itself? I have fungus on bottom of 1st lens Sad


PostPosted: Sat Apr 20, 2013 9:04 pm    Post subject: Reply with quote

xe0ps wrote:
Is there a way to open lens block itself? I have fungus on bottom of 1st lens Sad


Welcome! Depend from lens and knowledge, old lens blocks are usually open able by quality repair man in a difficult process.
Several manufacturer did start to use glue for example Carl Zeiss in Contax SLR line and basically not open able. Manufacturer did come to nasty , better to them if people throw away lenses and buy a new one than if they clean them. I did read on Zeiss page they not accept lens with fungus to fix it , due infect other lenses what a bullshit...


PostPosted: Sat Apr 20, 2013 10:12 pm    Post subject: Reply with quote

Attila wrote:

Welcome! Depend from lens and knowledge, old lens blocks are usually open able by quality repair man in a difficult process.
Several manufacturer did start to use glue for example Carl Zeiss in Contax SLR line and basically not open able. Manufacturer did come to nasty , better to them if people throw away lenses and buy a new one than if they clean them. I did read on Zeiss page they not accept lens with fungus to fix it , due infect other lenses what a bullshit...

Well, the talk about Minolta MD 1.7 50, and it's top lens block:



PostPosted: Sat Apr 20, 2013 10:51 pm    Post subject: Reply with quote

I think this is glued block you can't clean it at home for sure, to pay for clean not worth it, enjoy little fungus not impact picture quality.


PostPosted: Sat Apr 20, 2013 11:27 pm    Post subject: Reply with quote

I agree, clean what you can and don't worry too much about a tiny bit inside a sealed block. I've cleaned leses, with the excellent 'cold cream', and left the hard to get at elements alone. It's always improved the lens to get the large infestation out, but a little shouldn't be a disaster to the image.


PostPosted: Sat Apr 20, 2013 11:57 pm    Post subject: Reply with quote

+1
I have a super takumar 3.5/35 that came with fungus - a lot of it.
I cleaned it all, except the face of one element that is part of a sealed group: the lens works like charm, and I can't imagine it being more sharp or contrasty than it is now.
So, my advice is: store the lens right (in a dry, exposed to uv and dust free ambient) to make fungal growth as slow and difficult as possible, and clean what you manage without risking any damage to the lens.
There are good chances that you'll end up with a perfectly usable lens, with no noticeable differences from a clean one.


PostPosted: Mon Apr 22, 2013 11:30 pm    Post subject: Reply with quote

I never tryed to use cold cream for cleaning fungus. It was almost always cleanable with 50% aqueous IPA. If it wasn't then 100% IPA or water and soap did the trick. ....or I was lucky until know and never encountered "hard to clean" fungus?


PostPosted: Wed Apr 23, 2014 5:58 am    Post subject: Reply with quote

Hi, I'm sorry for posting on this thread which has been dead for a year and a day exactly... i've been a regular of this forum for about 2 years but this is my first post. I just wanted to thank you because I could fix my minolta 50mm 1.7 with these pictures.

THANKS!


PostPosted: Mon Nov 24, 2014 2:16 am    Post subject: Minolta MD 50 f1.7 - cleaning lens block Reply with quote

I've managed to clean the lens block.
A lot of trouble but it worked. This lens is so cheap, its better to buy another one. However if anyone is game, here's how to disassemble the sealed lens block.

There are 3 elements.
You cannot access the elements from the front. Go via the back.

I melted the glue from the base of the block using paint stripper. Just soak the bottom element. The bottom element just dropped out after 2 days.
The 2nd element is held together by a ridge on the plastic rim. This was the most difficult as there is no retaining ring - its just snaps into place. It's too tight to suck it out with a suction device. To get this out, I made a small hole to the side of the block in between the 1st and 2nd element, push a tooth pick inside and pushed the lens out. Be careful not to scratch the elements doing this.

Putting them back was was easy - the 2nd element just snaps into place with a little finger pressure. The 3rd element had to be re-glued. I used silicon, then repainted it black (the paint stripper had removed all the black paint).

No more fungus Smile Razz


PostPosted: Mon Nov 24, 2014 6:36 pm    Post subject: Reply with quote

I'm sure I read somewhere on this forum that an acid in hand cream/cold cream is what moves fungus. perhaps uric acid or boric acid that is harmless to minerals but works on organic materials.