The new lens looks really impressive: http://www.dpreview.com/news/0708/07082008canonef14mmii.asp

OTOH, that's a lot of money ($2 grand)! I'm wondering how/when you would use it uw instead of a 15mm FE, specifically on a FF camera. I've used the FE quite a bit, but haven't tried the old 14mm. I assume the attraction is that you don't get the FE distortion?

As its a rectilinear lens it will suffer all the corner problems associated with lenses with a FoV exceeding about 90 degrees when used behind a conventional dome port. It looks like this is another ungraded lens design intended to provide better edge performance, but as you might see from other discussions on wetpixel, this may not translate into better underwater edge/corner performance due to the optical constraints of dome ports.

Based on my experience with the original 14mm is behind a dome port, with which I could never achieve good corner performance (no matter what dome port or port extension I tried) I'm going to test the new 14mm in real life, behind a port, before buying. I'm hopeful, as this is a perfect focal length for many of us, but not overly confident. But, if it does work in the water, it could be a "must-have" tool. No doubt it will be a great lens topside.