focusing helicoid lubricant - what is it?

[phillinj]

I am interested in the composition of focusing helicoid lubricant because a lens I bought recently on eBay seems to be deficient. It focuses and holds focus ok for the most part, but there is no real drag when starting to turn, nor is there the 'push-back" upon stopping the turn. The lack of "stickiness" is unlike any other manual focus lens I have handled. In addition, the helicoid has a slight "dip" near infinity. I am wondering if the helicoid lubricant has broken down. Fortunately, the optics are good, so I guess I can't complain too much.

[Attila]

Can be happen need to relube with heat resistant 'hard' grease to avoid oil at summer time, if you open it wash out old grease with fuel and re-lube it after.

[Ramon]

I have found that there is no perfect grease that is suitable for all lenses, each lens seems to require something different.
I assume there are too many variables involved with differently made helicoids and the weight of the moving parts all needing different amounts of friction to make them work efficiently. So it is a case of trial and error.

Having said that I have had a fair amount of success with "Superslick" tuning slide grease that is designed for brass musical instruments but even that doesn't work for everything. Make sure you avoid Silicon grease because that can be really nasty if you get any on the glass.

[hinnerker]

Try this..

http://www.losimol.de/index.php/en/reference

[Lloydy]

I use a multipurpose grease, medium viscosity. A helicoid is a screw thread that's turned by hand, there's no high speed or great loads. The temperature range we use lenses in is reasonably moderate. Multipurpose grease is designed for such use.

A lot of people recommend molybdenum disulphide grease, and a lot of people apparently use it with no problems. But in a working career as an engineering maintenance fitter I saw little pools of oil on top of the moly' grease cans we kept in our workshop. The oil would seperate from the grease base when left undisturbed for a while. Other greases didn't, and I think it was that the moly' grease is metallic based and unless it is in reasonably constant motion it separates.
That's just my view though, and I'm sure people will say they've used it for years with no problem.

[Srdjan]

The easiest and cheapest way to relube lens is to use teflon based synthetic grease or lubricant. You can find sometime some of them in bike shop. The idea that grease or lubricant don't move when is once applied.

[Srdjan]

This is interesting text about how professionals do cleanin http://www.zeisscamera.com/services_lens.shtml

[philslizzy]