Lens lubrication

One of my non Pentax lenses developed a "sticking point" at the lower end of the zoom range. It's seen an enormous amount of use in fairly hot climates. I've previously had to do the same on one of my Pentax lenses, a Minolta 50mm macro and a Sigma zoom.

Front sticky cover on this lens needs removing.




Once removed




The three screws, once removed, allow the front element to be removed.

Three more screws allow removal of the shimmed second front element. Both seen together and also the pencilled on shim value (factory figure).

The shims are just visible at the bottom left side of the lens module




The only safe grease to use is Lithium grease.




I use cotton buds to apply the grease to the grooves and sliding faces inside the barrels. Any excess is easily removed with a clean cotton bud.

After the grease is applied, work the lens several times to distribute the grease observing for any build up lumps that are displaced by the cam groove followers and barrel sleeves. Again, remove with a clean cotton bud.

The internals




Once your happy with the job, carefully re-assemble and test the lens for focus shift (it should not happen and has not happened on any lens I've lubed).




Obviously, don't attempt this if your not competent or comfortable with such work. I have no issue opening lenses but would not consider opening up a camera body.

This particular lens was bought in 2009 and as far as I'm concerned, the need for a service was not an issue considering the very high use it's seen it now functions very smoothly.

Best regards

Thanks.

A good tip , thanks Gary.

Really handy hint there, thanks!

How did you get the front sticky cover off ?

The plastic "stick on" ring is carefully lifted by using a fine flat screwdriver blade between it and above a screw position as the screws sit in recesses, so offer an entry point as show below.




I've left part of the plastic cover lifted for this image so you can see how it would work. Great care needed so you don't touch the front element!

Best regards