Large manual focus lens focal stability

ghillindy1 · 11-25-2010, 12:06 AM

Does anyone have any suggestions regarding how I can point my large 300MM lens at the moon w/o it sliding back from maximun length? You would think the large lenses would havesome sort of lock function on them.

hal_a · 11-25-2010, 12:47 AM

I see no reason why it should slide back from infinity focus in the first place.

Now, if it was a push pull zoom, then it zoom creep (i believe that's the right term) could be an issue. Tell us what lens you are using. Then perhaps some knowledgeable forums user(s) can give you the right answer.

ghillindy1 · 11-25-2010, 01:17 AM

Yes, it is a push pull zoom, and it is "creep". The lens is a Sears 50-300. THANKS

Laurentiu Cristofor · 11-25-2010, 01:29 AM

Scotch tape?

rhodopsin · 11-25-2010, 01:42 AM

Moonrise or Moonset

Seriously, as suggested tape (masking or mounting, scotch leaves residue), or take it apart & re-grease the sliding parts with lower viscosity grease.

**Lowell Goudge** · 11-25-2010, 06:26 AM

why not stretch a rubber band around the barrel of the lens to block the sliding zoom collar. itr works pretty well on my Series 1 70-210F3.5

fotaki · 11-25-2010, 12:17 PM

I use a small section (5cm wide) cut from 50mm foam pipe insulation for my Tamron SP 60-300mm. Stops the creep and gives a nice chunky grip. Problem: sometimes you have to buy by the metre

Last edited by fotaki; 11-25-2010 at 02:55 PM.

hal_a · 11-25-2010, 03:42 PM

I would use gaffer tape instead because it leaves no residue. so your lens barrel won't be sticky (and get dirty afterwards). Gaffer tape is available in all hardware stores.

Hope this helps.

Lloydy · 11-26-2010, 10:49 AM

The silicon wristbands that many charities sell might be the right size to stretch over your lens and then push up against the creeping zoom slider? Some charities sell childrens sizes for sure.

I've used them for various uses over the years, they hold about 7 or 8 Cokin filter boxes together nicely, and I used four to replace the perished rubber zoom grip on a very scruffy old Vivitar lens some time back.

And you get to support a charity as well, always a good thing.

11-25-2010, 12:06 AM	#1
ghillindy1 Junior Member Join Date: Aug 2009 Location: Plainfield Indiana Photos: Albums Posts: 45	Large manual focus lens focal stability Does anyone have any suggestions regarding how I can point my large 300MM lens at the moon w/o it sliding back from maximun length? You would think the large lenses would havesome sort of lock function on them.

11-25-2010, 06:26 AM	#6
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,888	what about a rubber band? why not stretch a rubber band around the barrel of the lens to block the sliding zoom collar. itr works pretty well on my Series 1 70-210F3.5

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11-25-2010, 12:47 AM	#2
hal_a Forum Member Join Date: Aug 2010 Location: Montreal Posts: 60	I see no reason why it should slide back from infinity focus in the first place. Now, if it was a push pull zoom, then it zoom creep (i believe that's the right term) could be an issue. Tell us what lens you are using. Then perhaps some knowledgeable forums user(s) can give you the right answer.

11-25-2010, 01:17 AM	#3
ghillindy1 Junior Member Join Date: Aug 2009 Location: Plainfield Indiana Photos: Albums Posts: 45 Original Poster	Yes, it is a push pull zoom, and it is "creep". The lens is a Sears 50-300. THANKS

11-25-2010, 01:29 AM	#4
Laurentiu Cristofor Banned Join Date: Nov 2009 Location: WA Photos: Albums Posts: 3,055	Scotch tape?

11-25-2010, 01:42 AM	#5
rhodopsin Veteran Member Join Date: Dec 2009 Location: Deep Forest Posts: 643	Moonrise or Moonset Seriously, as suggested tape (masking or mounting, scotch leaves residue), or take it apart & re-grease the sliding parts with lower viscosity grease.

11-25-2010, 12:17 PM	#7
fotaki Veteran Member Join Date: Aug 2008 Location: Greece and UK Photos: Gallery \| Albums Posts: 309	I use a small section (5cm wide) cut from 50mm foam pipe insulation for my Tamron SP 60-300mm. Stops the creep and gives a nice chunky grip. Problem: sometimes you have to buy by the metre Last edited by fotaki; 11-25-2010 at 02:55 PM.

11-25-2010, 03:42 PM	#8
hal_a Forum Member Join Date: Aug 2010 Location: Montreal Posts: 60	I would use gaffer tape instead because it leaves no residue. so your lens barrel won't be sticky (and get dirty afterwards). Gaffer tape is available in all hardware stores. Hope this helps.

11-26-2010, 10:49 AM	#9
Lloydy Veteran Member Join Date: Aug 2007 Location: Shropshire, UK Posts: 1,114	The silicon wristbands that many charities sell might be the right size to stretch over your lens and then push up against the creeping zoom slider? Some charities sell childrens sizes for sure. I've used them for various uses over the years, they hold about 7 or 8 Cokin filter boxes together nicely, and I used four to replace the perished rubber zoom grip on a very scruffy old Vivitar lens some time back. And you get to support a charity as well, always a good thing.