Home

Please support mflenses.com if you need any graphic related work order it from us, click on above banner to order!
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Disassembling a Kiron 2/28
Post new topic   Reply to topic
Home   Equipment Care and Repairs
View previous topic :: View next topic  


PostPosted: Mon Oct 12, 2015 5:37 pm    Post subject: Disassembling a Kiron 2/28 Reply with quote
I acquired a neat Kiron 2/28 for a very good price because it has some fungus behind the front element, it seems either on the back of the front element, or on the one just behind.
I removed easily the nameplate, and accessed the front group, but I can't manage to unscrew the housing: is it possible that some kind of thread locking fluid was applied? Am I correct assuming that if I put a some drops of acetone carefully on the thread it will eventually unlock?
Or is there another way to access the back of the front element?


PostPosted: Mon Oct 12, 2015 6:52 pm    Post subject: Reply with quote
I have the same lens, but never disassembled it. Here is the optical scheme of the supposedly identical Vivitar 28 f/2:


(Source: http://forum.mflenses.com/kiron-28mm-f2-anyone-has-its-optical-formula-diagram-t35960.html)


It doesn't show much, but it looks to me as though the front element should come loose as soon as the name ring is off. If not, maybe two or three drops of Acetone can help. If you need to unscrew parts of the housing, a cap gripper is nice. Just don't apply too much pressure on the lens housing - if you deform it, you can't screw/unscrew the locking rings anymore Smile


PostPosted: Tue Oct 13, 2015 9:16 am    Post subject: Reply with quote
VLR wrote:

It doesn't show much, but it looks to me as though the front element should come loose as soon as the name ring is off. If not, maybe two or three drops of Acetone can help. If you need to unscrew parts of the housing, a cap gripper is nice. Just don't apply too much pressure on the lens housing - if you deform it, you can't screw/unscrew the locking rings anymore :)


I removed the front group easily after removing the nameplate - watching the diagram I'd say it contains the four front element - but the elements are locked in a metal housing. It looks like it can be opened by unscrewing the frontmost metal part, a sort of big retainer ring, but even applying a bit more force than it seemed reasonable, nothing moved. Probably the thread is locked with some kind of glue. I'll try with acetone, maybe. However, the fungus doesn't seem to have too much impact on the images, as the lens looks already pretty sharp at f2, with just a very small residual glow on very strong highlights. So i might as well leave it like it is.
However, thanks for the info and the diagram.


PostPosted: Tue Oct 13, 2015 4:49 pm    Post subject: Reply with quote
The "big retainer ring" - does it have two notches/grooves?


PostPosted: Tue Oct 13, 2015 5:22 pm    Post subject: Reply with quote
There is a set screw on the side of the front ring. Once you loosen it unscrewing the ring and removing front element should be child's play.


PostPosted: Wed Oct 14, 2015 7:53 pm    Post subject: Reply with quote
VLR wrote:
The "big retainer ring" - does it have two notches/grooves?


no, no groves for the spanner wrench, sadly. I will post a pic as soon as I manage to take it.


PostPosted: Mon Apr 25, 2016 2:04 pm    Post subject: Reply with quote
Hello everyone!

I experienced the same problem: I successfully removed some of the front as well as of the real lenses, but i found no way to remove the ones beside the diaphragm blades! And dirty was just there ... Sad
Post new topic   Reply to topic
Home   Equipment Care and Repairs
Page 1 of 1