Originally posted by IchabodCrane Unfortunately, one can only change lenses in an environment where weather resistance is not needed.
+1. This is a very important point in harsh conditions and too often ignored.
I work nearly 50% in harsh to very harsh environments, and lens swap is a no-no. I use also a 1-Body+1-lens system, most often with the DA18-135mm or DA18-250mm, or a prime (often my Voigtlander Nokton 58mm f1.4).
PS: I know that the DA18-250mm and are not labelled WR. Both were produced before the WR marketing 'trick' and both are very very sturdy lenses. See a number of PF discussion threads for example.