Pentax-M 1.4/50 disassembly problem

TrueLoveOne · Expire: 2013-12-24

I received one of these, at first sight it looks like it is in very good shape, no fungus visible. But if you hold it against a very strong light source you can see something that looks like spots from water or oil or something.... it's not like fungus at all. Looking straight through, you see nothing, only under an angle.

So i took it to pieces in order to give it a cleaning. All elements seemed to be removable very easy, but none of them had the spots!

After i had removed the lenses from the front end and the rear end one (or two) elements remained in the barrel, and yes: these showed the spots. However, this or these elements seem to be one piece, or at least i am not able to remove them. They are right behind the aperture mechanism, looking from the front.

I found a video on youtube, but the gentleman who made it left exactly this piece inside the barrel and only cleaned what he could reach. My problem is in between these elements, not on the front or rear of them.

Has anyone here ever took one apart and knows what to do? These spots will probably not affect pictures, but i just want it to be clean!

Thanks a lot in advance!!

Gardener · Joined: 22 Sep 2013 Posts: 950 Location: USA

They are one piece, called a doublet, that is two lenses glued together. There is no easy way to take them apart and then put back together.

TrueLoveOne · Expire: 2013-12-24

Thank you.

I was afraid it would be something like that. Too bad....

Cheers!

TrueLoveOne · Expire: 2013-12-24

Meanwhile i found a little booklet with all the Pentax lens schemes. My problem is indeed situated between the two connected elements.

hasan · Joined: 12 Mar 2007 Posts: 313

http://tomshome.sakura.ne.jp/others/LENS/M5014.html
and
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/192993-great-video-lens-repair.html

good luck!

PS: oh, just read you probably already watched this video...

calvin83 · Joined: 12 Apr 2009 Posts: 7588 Location: Hong Kong

Some of the Pentax M series lenses are prone to separation, for example the 50/1.4 and 100 macro .... no idea why.

TrueLoveOne · Expire: 2013-12-24

http://tomshome.sakura.ne.jp/others/LENS/M5014.html

Dang! That one looks really bad, but he separated the elements and put them together again all by himself, great job! (thank god for google translate!)

Well i guess i'll leave mine like it is. If you look straight through you don't see it. I still have to test if it affects image quality.

Thanks all for the input!