GMOG
Well-known
I'd like to pick your brains on grease options for helicals. I've used three different greases with mostly positive results.
I find that the braking resistance felt is a function of the grease's viscosity combined with the overall surface area of the helicals. Thicker greases work better in simple helicals, like the single ones found in the old Elmars, the 5cm and 3.5cm. For these I've used a grease known as "Fomblin". It's standard issue in the world of watches, used for lubing the rubber gaskets that seal the cases from dirt and water. I think this stuff is also used in electron microscopes for greasing of gaskets and sliding assemblies. For lenses with dual helicals and more surface area (like my old Nikkors) this grease gives too much of a damping effect, making it difficult to focus the lens.
For these more complex lenses I have experimented with two greases I got from Japan (eBay), and the one that seems best for these is the thinner grease (the #30). But there is a problem I am having with this particular grease that I don't quite understand. It works well in my old NIkkors, but it doesn't work well when used in my dual-helical Leitz lenses. The main difference between these lenses is the material used to make the helicals. It's aluminum in the Nikkors, and brass (mostly) in the Leitzes.
This is the grease I'm referring to:
So far I've used this grease when servicing two Summicron 50s, a "Rigid" and a Dual-Range. And both exhibit the same problem. The grease seems to have a multi-viscosity component to it that is working against me. When I pick up either of these lenses and first turn the focusing it goes as smooth as silk. But after I give the ring a few turns the resistance I feel changes, becoming a little stiffer, a little "grabby" when using light pressure. The problem here is when fine tuning focus. I have to use increased pressure to make the ring turn, and when it releases it often goes further than I want it to. The back and forth wastes time. This same grease does not behave like this in the Nikkors.
I'm certain that I've got the Leitz helicals as clean as they can be. Below are images taken when working on the DR (not the best focus, sorry):
I'm thinking that I need to use a different grease for these lenses, but I'm not sure which one. Based on your experiences what grease would you recommend? Does brass vs aluminum really make a difference?
Thanks for your time!
I find that the braking resistance felt is a function of the grease's viscosity combined with the overall surface area of the helicals. Thicker greases work better in simple helicals, like the single ones found in the old Elmars, the 5cm and 3.5cm. For these I've used a grease known as "Fomblin". It's standard issue in the world of watches, used for lubing the rubber gaskets that seal the cases from dirt and water. I think this stuff is also used in electron microscopes for greasing of gaskets and sliding assemblies. For lenses with dual helicals and more surface area (like my old Nikkors) this grease gives too much of a damping effect, making it difficult to focus the lens.
For these more complex lenses I have experimented with two greases I got from Japan (eBay), and the one that seems best for these is the thinner grease (the #30). But there is a problem I am having with this particular grease that I don't quite understand. It works well in my old NIkkors, but it doesn't work well when used in my dual-helical Leitz lenses. The main difference between these lenses is the material used to make the helicals. It's aluminum in the Nikkors, and brass (mostly) in the Leitzes.
This is the grease I'm referring to:
So far I've used this grease when servicing two Summicron 50s, a "Rigid" and a Dual-Range. And both exhibit the same problem. The grease seems to have a multi-viscosity component to it that is working against me. When I pick up either of these lenses and first turn the focusing it goes as smooth as silk. But after I give the ring a few turns the resistance I feel changes, becoming a little stiffer, a little "grabby" when using light pressure. The problem here is when fine tuning focus. I have to use increased pressure to make the ring turn, and when it releases it often goes further than I want it to. The back and forth wastes time. This same grease does not behave like this in the Nikkors.
I'm certain that I've got the Leitz helicals as clean as they can be. Below are images taken when working on the DR (not the best focus, sorry):
I'm thinking that I need to use a different grease for these lenses, but I'm not sure which one. Based on your experiences what grease would you recommend? Does brass vs aluminum really make a difference?
Thanks for your time!
