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07-01-2011, 08:44 AM   #1
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Location: Vellore, India
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tokina 400mm SD 'loose' aperture


I just acquired this (ebay). It is the A version.
However, I note that the aperture ring (and thus aperture) move VERY smoothly... and I dont perceive a click onto the next stop. I feel this is not right...

As it is the A version, I can use it on Av mode on my Kx and I want to feel it will not affect the picture... unless the aperture changes unwantedly.

Anyone else observed something similar? Comments/suggestions appreciated.


07-01-2011, 09:52 AM   #2
cmohr's Avatar

Join Date: Apr 2011
Location: Brisbane. Australia
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It sounds like the little ball bearing or spring on the ball bearing under the collar is missing, if you have ever diss-assembled a lens, its an easy thing to find, but finding the correct parts to fix it could be a hassle. If you are only going to use it in "A" mode you could try to lock it in place. Generally its a small 1mm spring and ball bearing on most lenses that gives that "click" feel, if your confindent, its not that hard to pull off the aperature collar and find if its missing.

I have run a strip of cardboard under an aperature collar to stiffen up the friction on the collar.....
07-01-2011, 11:48 AM   #3
Just1MoreDave's Avatar

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Location: Aurora, CO
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The aperture ring should click at each stop marked on the ring. It does on mine. It should also lock in the A position. I don't think I've ever moved mine away from the A position, where it should work fine and not be affected by the issue. It might affect resale value. Fixing it is as cmohr describes.
07-01-2011, 03:32 PM   #4
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Original Poster
thanks guys. shall keep you posted.


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