I don't have direct experience but I would tend to disagree, the 12mm f1.4 could fill the frame with 170mm long fish, 20 cm from the sensor or right on the dome, it would work for large fish but not so well for smaller ones. Similarly the 25mm would fill the frame with a 120mm long fish 25cm from the subject. I think the 25mm f1.7 would be very close in performance to the Panasonic 30mm macro which would have greater utility with close focus, a review of that lens is here. http://www.reefwreck...lens-underwater I just bought a port to use with the 30mm so will get to try it out soon.
That's the reason why I opted for the 25mm instead of the 30mm macro, the 1:1 magnification seems redundant if your working distance to achieve 1:1 is almost zero.