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02-03-2016, 12:20 PM   #1
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Pentax M Zoom 1.4 75mm-150mm

Dear All,

I have a Pentax M Zoom 1.4 75mm-150mm which is now in really good condition optically.

Upon purchase of the lens I had found that it had had haze and potentially some fungal growth
on the front element so I decided to disassemble the lens which I happened to do successfully.
The front element came of quite easily and what I had thought was going to be fungal damage to the lens
turned out to be simply residue left over from when the lens was most probably used outside on a beach somewhere.
There was sand in the screw threads.
The front element is now very clean.

Now to my problem.

I have successfully reassembled the lens except for one thing.

The focus is limited.

The focus ring with the focus screws in place
moves from infinity to only about 1.6 meters
When I remove the focus screws the focus ring moves
across the entire range throughout the entire focal length

Despite my best efforts I am at a loss to a solution

Has anyone here experienced the same thing or knows the solution?

Thank you very much in advance

02-03-2016, 12:23 PM   #2
bertwert's Avatar

Join Date: Jun 2015
Location: Golden, BC
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Posts: 5,518
Welcome to the forum!
I can't help with your question, but I'm sure other forum members can!
02-03-2016, 12:38 PM   #3

Join Date: Jun 2009
Location: GMT +10
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Posts: 10,893
There's a thread or two on this forum with some advice on repairing this lens - eg:

Best of luck! It's a great little lens.
02-03-2016, 12:58 PM   #4
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Join Date: Feb 2016
Posts: 5
Original Poster
I've had a read of the thread you've recommended.
It isn't quite what I'm looking for
Thank you none the less

02-05-2016, 10:12 AM   #5
New Member

Join Date: Feb 2016
Posts: 5
Original Poster
Quick update

I've found the solution to my problem.

The front element barrel needed to be fitted on so that the helicoid could align properly

All fixed now so pictures will be turning up

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