View single post by Robert
 Posted: Tue Feb 18th, 2020 23:17
Robert



Joined: Sun Apr 1st, 2012
Location: South Lakeland, UK
Posts: 4066
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chrisbet wrote:
A little confusion here - This is the only manual focus lens I have got and it certainly isn't as free as the AF lenses, so I was just asking whether this is normal behaviour for my lens - especially as it has two sets of helicoids.

I just checked, the word you used was "heavy", no MF lens should feel heavy to focus.  On the other hand, most of the AF lenses I have, feel overly slack to focus manually, quite horrible by comparison with the old MF lenses.

Heavy or stiff are not words which I  feel should be associated with the focus action of good MF Nikkor lenses. The grease may have stiffened, it may have been serviced in the past with the wrong grade of grease or it's suffering from lack of use. A good lens technician will know instantly if it's right or not.  I will try an experiment later to see if I can measure the torque required to turn the focus rings of my MF lenses with the simple expedient of wrapping a little thread around the focus ring and tugging with a spring balance.

Richard Haw is a well known lens expert who is keen to share his knowledge on manual lenses.

https://richardhaw.com

He is rather entertaining and very knowledgeable, it's well worth trawling his site, I would be surprised if he hasn't covered your lens or one very similar.  He covers greases and solvents (among many other things like making lens spanners etc.) in great detail in separate sections of his site.



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Robert.