Pentax SMC-M loose rubber focuser grips

Ephraim · 02-06-2023, 09:06 AM

Hello Pentaxi

I have a couple of beautiful, untouched SMC-M's with what appears to be loose rubber grips. They aren't "flimsy" and loose, but often if you just grip it very very lightly and turn, only the rubber turns without "catching" the focuser.

Is there a quick solution to this without opening an otherwise spotless lens? With only a couple of specks of dust, it would be a shame to have them lose their virginity over this.

**Bob 256** · 02-06-2023, 09:29 AM

These are typically just large "rubber bands" that are stretched over the outside of the lens in a grooved area. I'm not sure what you mean by "opening" the lens as that usually won't gain you anything in terms of your issue. What you might need to do is shove some small spacer strips under the rubber "band" to take up the slack since it seems the rubber has lengthened over time and is just slipping in that groove, not firmly engaging the lens body. Be careful however, as aged rubber has been known to break, and I have a couple of lenses whose rubber focusing bands have come completely off. However, they work perfectly ok without the rubber focusing bands.

Ephraim · 02-06-2023, 09:38 AM

Yes, these lenses are practically NOS in box so must have been just the effects of time...
I will try to pry it up a tad to shove a little piece of paper under it in 2 spots and see if that helps thank you!

jcdoss · 02-06-2023, 01:29 PM

Originally posted by Ephraim

...I will try to pry it up a tad to shove a little piece of paper under it in 2 spots and see if that helps thank you!

Keep us posted how this works out. I've got an M50f1.7 with this problem I'd like to fix.

pid · 02-07-2023, 04:17 AM - **1 Like**

something that helps with rubber: put it in cooking water and it will shrink again and getting softer again. Than clue it back to the lens.

Jonathan Mac · 02-07-2023, 05:35 AM - **1 Like**

I don't think I've ever seem this on a Pentax lens but have in some third-party ones including a Sigma 24/2.8 just the other week. I added a few dabs of super-glue in various places and it was fine. If the rubber is loose enough to pull back even a little then this should be possible.

02-06-2023, 09:06 AM	#1
Ephraim Forum Member Join Date: Feb 2023 Posts: 51	Pentax SMC-M loose rubber focuser grips Hello Pentaxi I have a couple of beautiful, untouched SMC-M's with what appears to be loose rubber grips. They aren't "flimsy" and loose, but often if you just grip it very very lightly and turn, only the rubber turns without "catching" the focuser. Is there a quick solution to this without opening an otherwise spotless lens? With only a couple of specks of dust, it would be a shame to have them lose their virginity over this.

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02-06-2023, 09:29 AM	#2
Bob 256 Site Supporter Join Date: Jun 2008 Location: Idaho Photos: Gallery Posts: 2,377	These are typically just large "rubber bands" that are stretched over the outside of the lens in a grooved area. I'm not sure what you mean by "opening" the lens as that usually won't gain you anything in terms of your issue. What you might need to do is shove some small spacer strips under the rubber "band" to take up the slack since it seems the rubber has lengthened over time and is just slipping in that groove, not firmly engaging the lens body. Be careful however, as aged rubber has been known to break, and I have a couple of lenses whose rubber focusing bands have come completely off. However, they work perfectly ok without the rubber focusing bands.

02-06-2023, 09:38 AM	#3
Ephraim Forum Member Join Date: Feb 2023 Posts: 51 Original Poster	Yes, these lenses are practically NOS in box so must have been just the effects of time... I will try to pry it up a tad to shove a little piece of paper under it in 2 spots and see if that helps thank you!

02-06-2023, 01:29 PM	#4
jcdoss Pentaxian Join Date: Nov 2012 Location: Ingelheim am Rhein, Germany Photos: Gallery \| Albums Posts: 6,795	Originally posted by Ephraim ...I will try to pry it up a tad to shove a little piece of paper under it in 2 spots and see if that helps thank you! Keep us posted how this works out. I've got an M50f1.7 with this problem I'd like to fix.

02-07-2023, 04:17 AM - 1 Like	#5
pid Pentaxian Join Date: Jan 2010 Photos: Gallery Posts: 567	something that helps with rubber: put it in cooking water and it will shrink again and getting softer again. Than clue it back to the lens.

02-07-2023, 05:35 AM - 1 Like	#6
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,911	I don't think I've ever seem this on a Pentax lens but have in some third-party ones including a Sigma 24/2.8 just the other week. I added a few dabs of super-glue in various places and it was fine. If the rubber is loose enough to pull back even a little then this should be possible.