Description
Use this Focus Gear from Sea & Sea to control manual focusing with your Canon EF 17-40mm f/4L USM lens in a compatible lens port, which mounts onto a Sea & Sea MDX underwater camera housing.The gear mounts onto the focus ring of the lens and is controlled via the required extension ring with focus knob. It does not work with the focus/zoom dial on the housing. It is constructed from a corrosion-resistant aluminum alloy.