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10-02-2018, 11:40 PM   #16
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Thank you for the tips. I’m in Brazil so wasn’t sure how “Canadian balsam” was marketed here, found the resin using the name of the actual pine tree species though. Apparently it has many uses, just need to make sure to get of the pure/clear type.

01-16-2019, 06:26 PM   #17
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QuoteOriginally posted by MysteryOnion Quote
I hope the coating was not eaten away... that looks very bad.

Its been a long time since I opened my M50/1.4, but the last group should be in a holder that is threaded into the aperture assembly... outer ring hook spanner and sleeve?

You considered boiling the group apart?
Starting with a cold pan and acclimate the group to the water then slowly raise the temp. The groups should sit on a cloth or thick towel to no overheat. The glue may soften at 184 degrees, but you should have a pair of tongs that can grip the elements and exert some torque. Do not lift out of the hot water during this heating process or the temperature difference could shatter the elements. Patience is needed, this may not work the first time and require multiple sessions to get the glue to fail.
use paint remover

---------- Post added 01-17-2019 at 06:57 AM ----------

QuoteOriginally posted by hcarvalhoalves Quote
Thank you for the tips. I’m in Brazil so wasn’t sure how “Canadian balsam” was marketed here, found the resin using the name of the actual pine tree species though. Apparently it has many uses, just need to make sure to get of the pure/clear type.
tryusing without cementing it works, it centers as much as the other elements
01-17-2019, 07:41 PM   #18
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QuoteOriginally posted by uttam.hathi Quote
use paint remover

---------- Post added 01-17-2019 at 06:57 AM ----------


tryusing without cementing it works, it centers as much as the other elements
yes, i'm using it now without any cementing, just that wide open at f1.4 a lot of flair, f2.8 to f5.6 is the sweet spots
04-19-2022, 12:42 PM   #19
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QuoteOriginally posted by hotfoo36 Quote
yes, i'm using it now without any cementing, just that wide open at f1.4 a lot of flair, f2.8 to f5.6 is the sweet spots
I know that the thread is old, but the problem still exists in some lenses, and solutions still need to be looked at. Literally...
I suggest using Edmund Optical Norland 61 UV-cured adhesive to re-cement elements, and if this needs removing, Dichloromethane, which can be obtained pure, but is also the main constituent of some paint strippers. Just pop the elements to be separated in a dish not affected by the solvent-glass will do, and leave until the elements separate. This can take up to 24 hours since the solvent has to reach the thin layer of 'cement'. If you buy the pure chemical, ensure the bottle is tightly closed because the chemical is VERY volatile! For curing the adhesive, a cheaply available UV emitting nail varnish hardening light works well, and often runs off a usb port.

04-27-2022, 11:52 PM   #20
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QuoteOriginally posted by martin42mm Quote
I know that the thread is old, but the problem still exists in some lenses, and solutions still need to be looked at. Literally...
I suggest using Edmund Optical Norland 61 UV-cured adhesive to re-cement elements, and if this needs removing, Dichloromethane, which can be obtained pure, but is also the main constituent of some paint strippers. Just pop the elements to be separated in a dish not affected by the solvent-glass will do, and leave until the elements separate. This can take up to 24 hours since the solvent has to reach the thin layer of 'cement'. If you buy the pure chemical, ensure the bottle is tightly closed because the chemical is VERY volatile! For curing the adhesive, a cheaply available UV emitting nail varnish hardening light works well, and often runs off a usb port.
thanks for the guidance. I'm too lazy to do now, lol
07-02-2022, 01:04 PM   #21
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QuoteOriginally posted by hotfoo36 Quote
Some in progress photos for the lens disassembly:
Code:
Code:
Code:
Code:
Hello hotfoo36! Can you share how you separated the cemented lenses? My Pentax-m 50 1.4 requires the same and I hope to fix it.
07-03-2022, 07:56 PM   #22
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QuoteOriginally posted by abubela Quote
Hello hotfoo36! Can you share how you separated the cemented lenses? My Pentax-m 50 1.4 requires the same and I hope to fix it.
Hello abubela,

It has been a few years when I did this and I can't remember correctly how I separate the cemented lenses. If my memory serve me well, I use a hot air blower to separate them, not using the boiling water method.

09-04-2022, 03:50 AM   #23
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smc pentax m 50mm f1.4

good day sir could tell me how do you clean the middle element of smc pentax m 50mm f1.4 i am confused how toclean this lens what materials do you used i saw your post last time
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