Hi Chris, I have done two reviews for the E-M1 II with Nauticam housing and Ikelite housings in issues #95 & #98 (current) uwpmag.com along with a review of the budget Olympus 30mm macro lens in issue #98. In both articles I said that I use the focus limiting switch set on the 1:1 to 0.4meter setting. This is the best working range for the lens and it helps with AF speed by not hunting as much. If you are having problems shooting in the 0.5 to 1.0 meter range in turbid water I am not surprised. The reason for using this lens is to shoot macro, other lenses like the 12-50, 12-40 and others are much more well suited to distances beyond 0.5 meters. Water works like a filter compressing to create a blue/green filter effect. Using a macro lens is like looking through a toilet paper roll tube at something a meter away, everything between the lens and subject is compressed in front of the lens. The AF can't tell the difference between your subject and the "floats" in the water column. So the answer to your question would be that I have used the E-M5 II and the E-M1 II extensively. The E-M1 MkII is better in every way including AF speed and AF target acquisition but the 60mm which is a great portriat and distance lens above water will just not work the same underwater. I have used this lens beyond 0.5 meters but in clear waters.