On Sat, 01 Feb 2003 19:21:12 GMT, "Joseph Meehan" <sligojoeSPAM2@hotmail.com> wrote:

>"Neuman - Ruether" <d_ruether@hotmail.com> wrote in message

>news:3e42ff71.5462793@newsstand.cit.cornell.edu...

>> On Fri, 31 Jan 2003 11:04:47 -0600, Mike Marty

>> <mikem@cs.NOSPAMwisc.edu> wrote:

>> ><snip>

>> >> In real life, with a few exceptions like a windy sandy beach or a

>> >> photographer who over-cleans his lenses, few photographers need the

>> >> protection of a filter. But then again, even a good one does not cost

>all

>> >> that much* and they are easy to use. The down side is they will very

>> >> slightly reduce sharpness and very slightly increase flare. It is a

>wash,

>> >> little gain and little loss.

>> There is no indication of sharpness loss with good filters,

>> in my experience...

> And I have seldom seen any aparent difference in sharpness or flare, I

>have tried over and over to keep in mind that there is a difference in some

>effect and a noticable or objectional effect.

????????????

>> >How often is "over-cleaning" a lens? There is always dust on my front

>> >lens element that I often breath on, and then wipe off with a "lens"

>cloth

>> >(which seems to be made of a ribbon-like material). I should probably

>> >just ignore dust and do this only when there is really a lot of crap on

>> >it, huh?

>> I suggest getting a good large hand air-syringe - this is

>> safer and more convenient to use and more easily packed

>> than environment-unfriendly "canned air", and it is

>> effective in removing dust from optical surfaces. I would

>> minimize rubbing glass surfaces (especially if done before

>> removing loose dust), and it is generally not needed

>> except to remove oil-based marks such as fingerprints...

> Again, I have seen very few examples of lenses damaged by even agressive

>cleaning (well back in the early days of coated lenses, it did not take much

>to mess up a coating, but I have not seen a coarting that soft in many

>years.

>> David Ruether

I have bought many a used lens, and I have seen a good

(well, bad, in the other sense...;-) proportion of them

visibly scratched and marred on the front and/or rear

glass surfaces, often quite badly. If you are lucky,

the scratches are not deep, and an ugly front can be OK

in practice (though the resale ease/value will be poor).

I agree that it is not as easy to scratch modern multicoated

lens outer surfaces, but I do not agree that cleaning

damage is rare - people still manage to damage lenses

rather too often. The simple use of a $10 filter can

prevent most of this...