OM 300mm f4.5

[HughofBardfield]

[Archphoto]

Re: OM 300mm f4.5

I did a lot of this kind of cleaning when I worked as a camera repairman.

Three things:
1) take photo's, lots of them
2) clean out all the old grease and oil very well
3) get the right grease and that will be the hard part.

As for the grease: you will need a synthetic lithium based grease with ultra low gassing, capable of handling high temperatures, so it does not run all over the place when left in the sun.
The best I have used so far is Mobilgrease 28 and Mobilith SHC 460.
Mobilgrease 28 is used in aviation for aircraft maintenance and is safe for aluminium and plastic's, so safe for use inside a camera.

My 2 cents,
Peter

[oly_om]

Re: OM 300mm f4.5

The aperture blades should be completely lubricant free - soak them in meths. The blades have knobbly pins on each side- one side fits into a set of holes, the other side into a set of curved grooves. Either the plate with the grooves or the holes rotates to alter the aperture- make sure each plate is grease free - again - meths - there should be no grease in the holes/grooves in contact with the blades or they will stick. When re-lubricating the other parts, use a heavy-ish lithium grease, not a light one or oil - otherwise the grease/oil will run over the blades again when the lens gets hot (e.g. when left in a hot car). The older lenses had grease that wasn't very temperature-stable - so if you have an old lens that is currently okay, don't leave it anywhere hot!

Andy

[snaarman]

Re: OM 300mm f4.5

I have cleaned two legacy lenses with oiled and stuck diaphragms. It was such a pig of a job I decided to never do it again. On that basis the price ain't that bad...

Pete

[HughofBardfield]

Re: OM 300mm f4.5

Thanks both... Hmmm. Sounds like I'll have to bite the bullet (or the cheque book). What annoys me is that I've hardly even used the damn thing since I bought it!