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[OM] Re: Vivitar Series 1 diaphragm

Subject: [OM] Re: Vivitar Series 1 diaphragm
From: Moose <olymoose@xxxxxxxxx>
Date: Sat, 03 Jun 2006 20:49:02 -0700
Don Holbrook wrote:
> Long time, quiet (till now), digest reader.  Have a 24-48/3.8 lens that the 
> diaphragm will not stop down.  f-stop ring & rear tab move ok, stopdown 
> button moves rear tab ok  Assume either stuck or linkage problem.  Can anyone 
> point out what to look for if I pull the center ring off the rear mount that 
> the tabs come thru, or lead me to a parts diagram that will show the linkage. 
>  Thanks in advance.  Off-list OK.  
>   
I don't know specifically about this lens, but there are a lot of 
similarities in those of various brands that I've had apart. Since the 
lens elements move as it is focused and/or zoomed, the mechanism that 
stops it down is generally some sort of long metal thingie that sticks 
deep down into the lens from the aperture stop down ring on the back and 
engages with some sort of tab on the diaphragm mechanism. Sometimes it 
is like a two pronged fork that engages the tab, sometimes ust a lever 
that pushes against the tab from one side.

I've dealt with a few lenses where this mechanism has come uncoupled, 
with the lever/fork slipping off/past the tab. Usually, well, every time 
so far, it has been possible to get it right easily. Not a bad idea to 
see if it needs a small amount of judicious bending towards the center 
so it will stay on in the future. The mechanism that controls the tab 
that conveys aperture setting to the camera body is similar, but so far 
always a fork, since it must positively locate the tab against pressure 
in both directions.

Take a close look at how the ring assembly is assembled before pulling 
out. You need to be able to get all the bits in the right places with 
the connections down into the lens body connected correctly all at once. 
On some lenses, it's easy, others are more challenging, easier perhaps 
with more hands. :-)

Moose

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