Dr E D F Williams wrote:
> Generally speaking people who scrub lenses (aaaaargh!) to clean them do it
> round and round and not radially. Radial marks are quite unusual and bear
> investigation merely because they are such. Lens cleaning is an art and
> should only be carried out by someone who is a master of that art.
{snip}
I took a lens to bits to clean it, once. It was an old 50mm lens which
had seen better days. I seem to recall using mild soapy water with lots
of rinsing, then leaving the elements to dry. The environment is not
exactly dust-free here so I ended up with a few bits of dust inside the
lens.
After reassembly the lens performed just fine. It looked much better
than before.
However I am _not_ willing to take my FA*400mm lens apart. And I doubt I
could trust the local repair agents to clean lens elements anyway. The
lens may be a little on the soft side at infinity but at least it still
functions :)
Cheers,
- Dave
http://www.digistar.com/~dmann/
