I be being dumb (probably - no need to rub it in!), but surely ALL lenses even primes without IF have moving elements - isnt this how focussing works, by moving certain elements in relation to others? Or does the entire enclosure move as one so focussing is purely down to the distance between the assembly and the film plane?
> -----Original Message----- > From: Sas Gabor [mailto:sas.gabor@;fornax.hu] > Sent: 13 November 2002 09:58 > To: [EMAIL PROTECTED] > Subject: Re: Dust in Lenses > > > Hi, > > On 12 Nov 2002 at 21:41, Bojidar Dimitrov wrote: > > This is just a hypothesis, but I would guess that non-IF, non-FREE > > lenses have elements fixed with relation to each-other, so > there is no > > air movin between the glass surfaces. IF and FREE lenses do have > > elements moving WRT others, so there is also air-flow, and thus an > > influx of dust. > > This is true for primes. > And even those have that annoying small metal parts called aperture > blades moving between the lenses... > > > Gabor > >
