[mst]

I don't think that any zoom lens that changes its length during zooming will behave better in this regard ... or at least those conditions. Tha volume of the lens changes with zooming, so does the volume of air inside the lens, of course. It will suck in moisture saturated air, that condensates on the inner lenses.



So, I guess the only real solution would be a zoom length with constant length. Which would translate to the 70-200 IS w/ TC. Or a Sigma 100-300/4. Maybe a 100-300/4 OS, if that ever happens.



-- Markus