You need the shorter port otherwise the 30mm will focus inside the port glass at closest focus. I'm thinking of a 30mm macro for similar reasons, I'd like to shoot weedy sea dragons and fish when on macro dives. It's all about compromises, getting 1:1 subjects will be harder with 30mm as you need to be closer, but if you don't use the 1:1 magnification so much then it makes sense. A zoom generally doesn't get you close enough for a lot of subjects like smaller nudis.
I'm thinking I might try the panasonic 30mm macro, it's f2.8 rather than f3.5 and test reports show it's sharper. Don't forget that the 60mm is equivalent to 120mm full frame, 60-90mm seems to the commonly used macro lens focal length for DSLR users.
Chris, do you know if any of these other shorter lenses work with wet lenses? Like the Inon wet lenses or the SubSee +5 or +10 Diopter? Because that could add a lot more functionality to these shorter macro options I would think.
- bmorescuba likes this