Today, weathersealing is taken for granted as a common, although not ubiquitous, feature in cameras. Over 30 years ago, however, it was rare in professional SLRs (the Pentax LX being the only model with what would now be considered to be even a modicum of such protection) and non-existent as far as any enthusiast or consumer-level 35mm model went. A plastic bag and some elastics were the standard means of improving the survivability of your rig in the rain or at the beach, with all of the compromises that implies. The time was ripe for innovation. And who better than Olympus to shake things up?
Suffers from a quarter-century and counting film and manual focus SLR addiction. Has recently expanded into 1980's AF point and shoots, and (gack!) '90s SLRs. He even mixes in some digital. Definitely a sick man.