Not in my humble opinion, Cotty, not so long as parts of the lens body needs to move in relationship to other parts, all on the same axis. That there is and will be a "trapped" volume of air inside at full extension, that needs to squoosh out while shortening the lens assembly to minimum length...that's indisputable. So also does the air need to come back inside when the lens is extended once again. So, shooting zooms in dusty circumstances is fraught with concern about all the powder-fine particles coming inside and depositing. I don't have an answer, because when you need a zoom, you need a zoom. You can't always operate with 'due diligence' (speed!) using primes all the time.
In fact, in a dusty environment, I think I'd be even more concerned about exposing the inside of my camera body to that dust when I change lenses! So, I think I'll stay with a zoom when circumstances dictate, and factor in the cost of a CLA everytime I can't stand the look of all that dust inside! And, maybe even find less dusty venues for my photographc interests! <g> keith whaley * * * Cotty wrote: > > On 17/10/03, [EMAIL PROTECTED] disgorged: > > >I wonder if Canon "sealed" L lenses are dust free? > > > >Alan Chan > >http://www.pbase.com/wlachan > > > >>Which brings an interesting possibility - creating a vacuum > >>inside............ > > Actually, I may be talking a load of nonesense here. What is the general > opinion regarding dust in lenses - am I right that it gets slowly sucked > in over the years through pressure difference?? > > Can you really have a totally sealed lens?? > > Cheers, > Cotty
