Happy New Year to all. The latest issue of Underwater Photography Magazine, UWPMAG.com posted today with my articles on the Sony FE 16-35mm zoom and Ikelite Gamma II flashlight. uwpmag.com is a free PDF downloads, which is loaded with interesting new articles on underwater photography. This article relates to using the Sony FE 16-35 zoom with A7 II and A7r II for underwater photography.
Underwater wide angle photography requires much wider lenses than land photography because you need to be very close to the subject, that is why fisheyes are used so much U/W. The 28mm with fisheye or wide adapter requires the same 170mm port used with the 16-35. The 35 is all but useless because of its minimum focus distance which would not work well behind a dome port. So the 16-35 zoom presents the best option for wide angle rectilinear photography with a Sony FE lens. Keep in mind that all of this equipment is used in a housing with a rather large port so lens size is less relevant that it is on land. Also the Sony A7 series reduce the overall housing size V. say a Nikon D800/810 because for the same lens range Nikon 16-35 zoom you would need a 230mm port to get the same corner sharpness you get with the 170mm port using mirrorless.