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How are zoom lenses driven?



 
 
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  #1  
Old September 30th 08, 03:24 AM posted to rec.photo.digital
J.C.
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Posts: 7
Default How are zoom lenses driven?

I'm having weird trouble finding usable diagrams of "super zoom" internals,
or any zoom for that matter. Cutaways show the glass and OIS, but how are
the sleeves aka barrels actually moved?

I imagine it would either be rack & pinion, with cogs in a straight line on
a sleeve and motorized gears grabbing them from the sides. Or is it rubber
friction rollers on the barrel, like a tape deck drive?

Specifically, what motor/gear system powers 12X+ Lumix/Leica lenses? My
camera is a FZ18. Any links to diagrams would help. Thanks.

J.C.
  #2  
Old September 30th 08, 03:51 AM posted to rec.photo.digital
Eric Stevens
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Posts: 13,611
Default How are zoom lenses driven?

On Mon, 29 Sep 2008 21:24:08 -0500, "J.C." wrote:

I'm having weird trouble finding usable diagrams of "super zoom" internals,
or any zoom for that matter. Cutaways show the glass and OIS, but how are
the sleeves aka barrels actually moved?

I imagine it would either be rack & pinion, with cogs in a straight line on
a sleeve and motorized gears grabbing them from the sides. Or is it rubber
friction rollers on the barrel, like a tape deck drive?

Specifically, what motor/gear system powers 12X+ Lumix/Leica lenses? My
camera is a FZ18. Any links to diagrams would help. Thanks.

There is usually a rotary cam somewhere, which works like a coarse
thread to move something backwards or forwards.



Eric Stevens
  #3  
Old September 30th 08, 07:45 AM posted to rec.photo.digital
Paul Furman
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Posts: 7,367
Default How are zoom lenses driven?

Eric Stevens wrote:
On Mon, 29 Sep 2008 21:24:08 -0500, "J.C." wrote:

I'm having weird trouble finding usable diagrams of "super zoom" internals,
or any zoom for that matter. Cutaways show the glass and OIS, but how are
the sleeves aka barrels actually moved?

I imagine it would either be rack & pinion, with cogs in a straight line on
a sleeve and motorized gears grabbing them from the sides. Or is it rubber
friction rollers on the barrel, like a tape deck drive?

Specifically, what motor/gear system powers 12X+ Lumix/Leica lenses? My
camera is a FZ18. Any links to diagrams would help. Thanks.

There is usually a rotary cam somewhere, which works like a coarse
thread to move something backwards or forwards.


Argh, there's a better word but yeah you described what I found in the
focusing mechanisms of old lenses I've dissasembled (focus is the same
as zoom). I've got an old slide projector lens with the coarse thread
groove and a metal dowel to follow that which is rather crude compared
to a smooth gliding manual focus lens but that may be the solution for
AF lenses which need to be able to move with less friction. For manual,
friction gives more control, for auto it requires big heavy motors.

Sorry no real help.

Ah the word is 'focusing helix' I think.
http://images.google.com/images?hl=en&q=focusing helix


--
Paul Furman
www.edgehill.net
www.baynatives.com

all google groups messages filtered due to spam
  #4  
Old September 30th 08, 08:56 AM posted to rec.photo.digital
Paul Furman
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Posts: 7,367
Default How are zoom lenses driven?

the word is 'focusing helix'
http://images.google.com/images?hl=en&q=focusing+helix


link fixed
  #5  
Old September 30th 08, 09:10 AM posted to rec.photo.digital
Clair Johnston
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Posts: 32
Default How are zoom lenses driven?

J.C. wrote:
I'm having weird trouble finding usable diagrams of "super zoom" internals,
or any zoom for that matter. Cutaways show the glass and OIS, but how are
the sleeves aka barrels actually moved?

I imagine it would either be rack & pinion, with cogs in a straight line on
a sleeve and motorized gears grabbing them from the sides. Or is it rubber
friction rollers on the barrel, like a tape deck drive?

Specifically, what motor/gear system powers 12X+ Lumix/Leica lenses? My
camera is a FZ18. Any links to diagrams would help. Thanks.

J.C.

Try the Panasonic web site. I was able to get the repair manual from
them for about $10 US to fix my wife's TZ3 after she has dropped it.

Clair
  #6  
Old October 1st 08, 02:28 AM posted to rec.photo.digital
J.C.
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Posts: 7
Default How are zoom lenses driven?

Eric Stevens wrote in
:

On Mon, 29 Sep 2008 21:24:08 -0500, "J.C." wrote:

I'm having weird trouble finding usable diagrams of "super zoom"
internals, or any zoom for that matter. Cutaways show the glass and
OIS, but how are the sleeves aka barrels actually moved?

I imagine it would either be rack & pinion, with cogs in a straight
line on a sleeve and motorized gears grabbing them from the sides. Or
is it rubber friction rollers on the barrel, like a tape deck drive?

Specifically, what motor/gear system powers 12X+ Lumix/Leica lenses?
My camera is a FZ18. Any links to diagrams would help. Thanks.

There is usually a rotary cam somewhere, which works like a coarse
thread to move something backwards or forwards.


Can you be more specific or direct me to an image? I'm now picturing a non-
round (rubber?) roller grabbing the inside of the barrel at its high
points.

What I'm mainly trying to find out is whether these are hard-gear driven,
and subject to stripping (of said gears) if the lens is moved manually.

J.C.
  #7  
Old October 1st 08, 02:30 AM posted to rec.photo.digital
J.C.
external usenet poster
 
Posts: 7
Default How are zoom lenses driven?

Clair Johnston wrote in
:

Try the Panasonic web site. I was able to get the repair manual from
them for about $10 US to fix my wife's TZ3 after she has dropped it.



Sounds promising, but can you describe in detail or post an image of the
drive mechanism? I was hoping for a free answer here!

J.C.
  #8  
Old October 1st 08, 04:42 AM posted to rec.photo.digital
Eric Stevens
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Posts: 13,611
Default How are zoom lenses driven?

On Tue, 30 Sep 2008 20:28:53 -0500, "J.C." wrote:

Eric Stevens wrote in
:

On Mon, 29 Sep 2008 21:24:08 -0500, "J.C." wrote:

I'm having weird trouble finding usable diagrams of "super zoom"
internals, or any zoom for that matter. Cutaways show the glass and
OIS, but how are the sleeves aka barrels actually moved?

I imagine it would either be rack & pinion, with cogs in a straight
line on a sleeve and motorized gears grabbing them from the sides. Or
is it rubber friction rollers on the barrel, like a tape deck drive?

Specifically, what motor/gear system powers 12X+ Lumix/Leica lenses?
My camera is a FZ18. Any links to diagrams would help. Thanks.

There is usually a rotary cam somewhere, which works like a coarse
thread to move something backwards or forwards.


Can you be more specific or direct me to an image? I'm now picturing a non-
round (rubber?) roller grabbing the inside of the barrel at its high
points.

What I'm mainly trying to find out is whether these are hard-gear driven,
and subject to stripping (of said gears) if the lens is moved manually.

I don't think there is any single simple answer to your question. It
all depends on the lens.



Eric Stevens
  #9  
Old October 1st 08, 01:19 PM posted to rec.photo.digital
Clair Johnston
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Posts: 32
Default How are zoom lenses driven?

J.C. wrote:
Clair Johnston wrote in
:

Try the Panasonic web site. I was able to get the repair manual from
them for about $10 US to fix my wife's TZ3 after she has dropped it.



Sounds promising, but can you describe in detail or post an image of the
drive mechanism? I was hoping for a free answer here!

J.C.

Let me get this correct. You want me to spend an hour or more of my
time so that you can save $10?

Clair
  #10  
Old October 1st 08, 09:40 PM posted to rec.photo.digital
---------------
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Posts: 30
Default How are zoom lenses driven?

No doubt they are delivered in large trucks like most consumer goods.


 




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