Shortsonfire79
Registered
The 12-40mm is a great lens, but which housing do you have? If I recall correctly the EM-5 II Oly housing has the Pen port system (smaller) and you can't use the 12-40mm with it in the olympus system of ports. You would need to use with after market ports like this one:
Athena Optical Dome Port WZ7-14II (Olympus EP Mount)
I use the 12-40 2.8 pro with the Meikon housing:
Olympus E-M5 II 40m/130ft Meikon Underwater Camera Housing with Dry dome port V.4
I have the Olympus housing; you're correct in thinking that the 12-40mm won't fit. According to this chart I'd need a port PPO-E02 for the 12-40mm. I see now that it's been discontinued but still available from third party retailers. That Athena port is way out of my budget, wow!
I didn't have any immediate plans to bring the 12-40mm underwater, but that Meikon housing is pretty reasonably priced. I might make the effort to sell the oly housing and pick that one up!