I know there has been much discussion about push-pull zooms and dust. But, this was a new one to me;
Internal zoom means no barrel extension to get dust in the lens.
This got me thinking (and I'm not trying to start a new "war' here) how much of the "dust in the lens" debate is fact and how much is fiction? I guess I've always assumed that most lenses are pretty much sealed environments. You need to protect the rear element with a cap and the front with either a filter or a cap or both (although the front elements seem pretty well sealed to me.)
But, as for dust getting inside a lens either from focusing or zooming, is that really likely? Sure, no system is going to be perfect and dust is pretty persistent, but are lenses really designed in ways that can allow dust to get in like this, or are we just repeating urban legends?
Aside from anecdotal evidence (I own the XYZ lens and it is a dust magnet or I own XYZ and I've never gotten a speck of dust in it) can anyone shed some light on this?