I currently shoot my 12-40 behind the Olympus PPO-E02 flat port in the Oly housing for my M-1. I took a chance and ordered the Inon 170mm dome meant for 4/3 lenses; as I thought, the dome port by itself is too short. Turns out it's still a few mm short with my 1" extension, so I have a 2" extension on the way. Does anyone here have experience shooting this lens behind the Inon dome? Is 2" enough? I'm guessing it's ok to stack extensions, but I don't want an extra leak point if I can help it.
