Kinefinity EF Adapter 3 Combo with Electronic ND

The EF 3 Mounting Adapter puts an electronic ND filter behind the lens, so exposure can be pulled without a matte box or a filter change, and it does it on the active locking mount used across the EF II series. What changed against the earlier adapter is how the lens goes on: as well as the usual DSLR clockwise rotation, the mount actively locks the lens the way a PL mount does, which is what a follow focus needs to stay in register.

The difference between this part and the plain EF 3 adapter is what ships with it. The Combo includes a regular EF mounting adapter alongside the e-ND version, so a camera can go out with the electronic ND on the A camera and a standard EF mount available for a second body or for the shot where the filter is not wanted. Order the Combo when you want both; the standalone EF 3 Mounting Adapter is a different part number.