Sorted at last?
I do think a 17mm shift lens is on the distant horizon, i decided the 70-200 f2.8L was too heavy and i don't tend to shoot tele very much, which is why the 100-300L hasn't seen an upgrade, the 135L serves quite well and sits right in the middle of 70-200, but i do see the need for zoom capability often - I think the F4 IS version would cut it for me
100-300L is actually pretty good, better than the 70-300 IS i used to own (and shouldn't have sold), unfortunately f5.6 through the whole range and 300mm needs at least f8 - but your right, probably wouldn't cut it now days - it is better than my 24-105 at 100mm even wide open, painful to focus though.....so.... slow....
not a fan of fisheyes, although could be cool to use underwater to shoot fishes eyes
Underwater housing... now that would be cool.