I-50 has Stiff Focusing - what to use...

Have you tried just exercising it for a half hour? Sit down, watch a favorite tv serial, and while watching rotate the focus back and forth.

If that doesn't work, the kiev survival site might help in dissection of the lens.
 
erikhaugsby said:
Have you tried just exercising it for a half hour? Sit down, watch a favorite tv serial, and while watching rotate the focus back and forth.

If that doesn't work, the kiev survival site might help in dissection of the lens.

I will try that.

But since the focusing treads are partially exposed as the lens is focused, I figured a few drops of some kind of lubricant may be in order. It is a collapsible lens (Elmar F/3.5 Clone)
 
You may not even have to disassemble the lens to relube it. The helicals are exposed and you can re-oil it by just applying the lubricant on the exposed helicoids.

However if the lens is really stiff from dirt and old fossilised grease on the helixes, you may have to take it apart. Not really hard to do- see here:

http://jay.fedka.com/index_files/Page325.htm

Grease to use: I have been using "Syncolon Super Lube" synthetic grease. You can also use automotive axle grease. The latter may have the consistency which works best with soviet lens helicals.

Jay
 
Jay, have recently done this job on my Fed collapsible,and used a very small smear of Vaseline--White Petroleum Jelly,as the lubricant on the thread,applied with a cocktail stick.The lens focusses fine,do you think it will be ok in the long term.

Strangely I have just also recalled that when I got my first Zenith SLR and M42 lenses,I read somewhere that the oil on the skin of my brow would be the ideal lubricant for all the threads on the lenses and camera. mounts.I followed this advice,applying the oil with a finger and never had a tight or fouled-up thread.Of course it helps if you have reasonably oily skin😀

Brian,
 
erikhaugsby said:
Have you tried just exercising it for a half hour? Sit down, watch a favorite tv serial, and while watching rotate the focus back and forth..
Same here, I had a FED-50 that was gritty when I got it. I didn't do anything about it, just accepted it as part of the FSU experience. But after a while of use, it has become real smooth without being loose.
 
SCOTFORTHLAD said:
Jay, have recently done this job on my Fed collapsible,and used a very small smear of Vaseline--White Petroleum Jelly,as the lubricant on the thread,applied with a cocktail stick.The lens focusses fine,do you think it will be ok in the long term.

Strangely I have just also recalled that when I got my first Zenith SLR and M42 lenses,I read somewhere that the oil on the skin of my brow would be the ideal lubricant for all the threads on the lenses and camera. mounts.I followed this advice,applying the oil with a finger and never had a tight or fouled-up thread.Of course it helps if you have reasonably oily skin😀

Brian,


Brian,

Petroleum jelly should probably work fine in certain instances. It should do with the Industar-50 collapsible where the helicals are exposed. The only issue with petroleum jelly is that it tends to run when temperatures go high.
The worst that can happen is that the liquified jelly will run, but it will run in places which can easily be wiped or cleaned. With sealed barrels, this may not be so good since the migrating lubricant might go to places where it shouldn't be in.

For the same reasons, Vaseline PJ does not go well as hair-dressing in the tropics, - it did a good job in keeping Elvis's pompadour in place- but not in hot weather. 😀

Also, the simple helicals of the I-50 and I-22 do not require too much of the grease used in them, aside from providing lubrication. The more complicated helicoids, like those found in the J-9, do require a certain viscosity to prevent the threads from slipping. The accuracy of the focus and coupling movements in these complex helicoids partly rely on the dampening provided by the thickness of the grease used. I've seen examples of J-9 where the lube put in them was too thin, making them focus erratically.

Jay
 
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