Dust in the focus ring.

[Bob Hart]

Sometimes and I emphasise only sometimes, if your camera has been dusted, it is helpful to soak a piece of letter or A4 copy paper with melted candlewax, lift it out, let it drain let and set. If there is excessive wax on the surface, lay it on another paper and give it a few minutes under a hair drier to wick the excess away. Make a duplicate set of pieces out of non-waxed paper for final clean-up.

Cut this waxed paper and the non-waxed paper into strips and smaller squares, then divide the squares into triangle halves of squares. After a dusting, use the pointed corner to work around the gap either side of the ring, diving under and hooking out imaginary bits of sand. The sooner this is done, the better.

After going all around, use a long edge and draw this through the gaps then make note of where you stopped on the ring and go back with a point and hook out again in the area you stopped at. After the task is completed, do the same thing with your peices of unwaxed paper to remove any oily residues which will retain future sand and dust.

When bits of sand are rolling between the edge of the ring and its channel and grinding away, one might be persuaded to keep working and fix it that night. By that time it may have worked its way under the ring and from there its journey will continue.