Forgot Password
Pentax Camera Forums Home

Show Printable Version Search this Thread
05-30-2013, 12:30 AM   #1
Senior Member

Join Date: Jun 2008
Location: Dallas, TX
Posts: 110
Aperture ring ball bearing size and availability for M50 1.7

Well I thought I was being careful...

But since I'm asking, obviously something went wrong.

I'd like to find a replacement ball bearing that provides the aperture clicks on my M50 1.7

To do that I need two bits of info. 1) is the size in case I were to order my own (likely in a package of 100 or some crazy amount). 2) would preferably be someone who was in my same position and might just happen to have one of their remaining 99 to spare for a reasonable price.

Any help on either front would be greatly appreciated!

05-30-2013, 01:06 AM   #2
Not a Number's Avatar

Join Date: Mar 2012
Location: Venice, CA
Posts: 4,263
05-30-2013, 01:44 AM   #3
Site Supporter

Join Date: May 2012
Location: Adelaide
Photos: Gallery | Albums
Posts: 1,104
Might just be easier to acquire a broken/crappy M lens of similar physical size. Can't imagine that the aperture ball wasn't a shared part over multiple lenses.
05-30-2013, 11:29 AM   #4
Junior Member

Join Date: Mar 2013
Photos: Albums
Posts: 41
Or aquire an A lens and use its ball. That way you have 2 usable lenses Clickless aperture might be cool for video - has anyone tried?

05-30-2013, 11:39 AM   #5
Veteran Member
crewl1's Avatar

Join Date: Jul 2010
Location: Los Angeles, CA
Photos: Gallery | Albums
Posts: 9,797
QuoteOriginally posted by kakapo Quote
Clickless aperture might be cool for video - has anyone tried?
News Shooter | The Lens Doctor: De-clicking in the UK
05-31-2013, 09:02 AM   #6
Just1MoreDave's Avatar

Join Date: Feb 2007
Location: Aurora, CO
Photos: Gallery | Albums
Posts: 4,863
I am pretty sure that the M50/1.7 bearing size is 2mm, shared with many other M series lenses. I have never measured it. Smaller bearings work but don't feel right. The typical A series size is 1.5mm, a measurement I am sure of. Micro-Tools has suitable bearings in bags of 5 for reasonable costs.

The clickless aperture ring for video is a great trend for lens disassemblers like me. Now there is a market for losing parts! The typical Pentax design uses a bearing and spring to take up any slack between the lens body and ring. Without the bearing, the clicks go away but the ring won't be damped like a focus ring either. The friction will depend on machining.
05-31-2013, 09:26 AM   #7
Site Supporter
altopiet's Avatar

Join Date: Sep 2010
Location: The Great Karoo, South Africa
Photos: Gallery | Albums
Posts: 1,927
One of the wonders of the world "How do aperture ball bearings disappear"

I talk under correction , but the one I actually removed from my M50/1,4 with the aperture lever, was 1.5mm if I remember correctly. Easier to use in Av, and soundless operation if you shoot video...
05-31-2013, 09:40 AM   #8
Site Supporter
Jean Poitiers's Avatar

Join Date: Apr 2011
Location: Lost in translation ...
Photos: Gallery | Albums
Posts: 16,551
Yes, Micro-Tools has them, but I have found that it's OK without the click bearing ... lost one recently is the re-lubing of a Helios 44M-4 ... J

05-31-2013, 04:22 PM   #9
Senior Member

Join Date: Jun 2008
Location: Dallas, TX
Posts: 110
Original Poster
Micro-Tools, here I come!

Thanks for the recommendation. From memory it looked closer to 1.5mm so I think that's what I'll go with. Hopefully it will work.

  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
aperture, ball, k-mount, m50, pentax lens, size, slr lens
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
Missing ball bearing. J.Scott Pentax SLR Lens Discussion 15 12-12-2015 05:19 AM
Aperture compared to glass size djmundy Troubleshooting and Beginner Help 13 10-31-2012 06:09 AM
K 28mm f3.5 aperture bearing Chaos_Realm Pentax SLR Lens Discussion 6 03-15-2012 06:51 PM
Use of Aperture-Ring 43mm/1.9 -> no aperture data Deimo Pentax SLR Lens Discussion 7 06-24-2009 03:25 PM

All times are GMT -7. The time now is 04:51 PM. | See also:, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]