On 10 Jan 2002 at 11:18, Mike Gezing wrote: > After looking at all my lenses in > this manner I found that particles of dirt were more prevalent in zoom > lenses vs primes and appeared to a greater degree in size and number in > older lenses vs new. In fact my three newest lenses all primes were clean. > > Has anyone one read any material on this matter or done any testing to see > if this is a real problem. Again I was not seeing dust but what appeared to be > small flects of paint.
Hi Mike, Zoom lenses collect more dust over time since as the lens is zoomed it's displacement changes hence air has to rush in to fill the new space, prime lenses are far less problematic in this instance and some IF lenses don't change their displacement during focussing at all. Many lenses including expensive Leica glass have dust in them on initial delivery, mostly it's not a problem. If you have to use a halide light at a curious angle in order to see them isn't probably not that big a deal. If however there are big noticeable chunks (often flaked paint or the product of wear in older lenses) then maybe it should be cleaned. However there really needs to be a lot of junk in a lens for it to make a visible difference. Cheers, Rob Studdert HURSTVILLE AUSTRALIA Tel +61-2-9554-4110 UTC(GMT) +10 Hours [EMAIL PROTECTED] http://members.ozemail.com.au/~distudio/publications.html - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
