[popo]

I'm not adverse to consider changing systems, but I'm not sure anything other system right now gives any benefit. I guess I should emphasise that rain use is not that frequent for me, but it does happen.



Olympus SLRs are a dead system. I wouldn't buy it new at this point, and since no one else did previously they're not common used either. I used to have their 4/3 70-300 lens and from memory that didn't appear to have any particular sealing either. Don't recall there being anything else in that area?



Pentax WR lenses didn't seem that big a choice last time I looked. Doesn't appear to be anything on the longer end.



I have even thought it might be an option to buy a 2nd 100-400L as they're not bad priced on the used market. While it wouldn't be sealed either, I would effectively double my rain exposure tolerance! And it never hurts to have backup... but I think the advantages of the 70-300L being smaller means I'd get slightly different capability at other times.