???
I think you are mistaken Bob - mine has a metal sutter that closes over the lens when the camera is switched off.
In addition the lens is sufficently recessed (and small) to be better protected than my DSL lenses with their hoods.
Finally we have never wiped the lens, and never had any distortion effects either - but we do give it a rinse off under the tap and a good shake after UW trips in salt water.
Above is 720SW (same as the 725/730/770) and I believe will apply equally to 790SW although the body has small changes in construction as well as updated software.
Ah, well Duncan, that'll be the difference between your Olypmus and my (the wife's, actually) Pentax Optio, then.
It doesn't have a lens cover, and we've got the photos to prove that it takes great photos of water droplets.
BF