A special extension is available for use with Nikon 105mm VR Macro and Canon 100mm USM Macro lenses. Manual focus is adjusted with a large, easy-to-turn knob on the side of the extension. For use with either #5510.16 or #5510.22 Port Bodies.
Unlike the standard focus ports for these lenses, this combination allows the user to alternate between manual and auto focus while the camera is installed in the housing
The Focus Extension can be used in place of the 1.75" Standard Extension in most instances. Note: The Focus Extension should not be used with the bayonet-style #5510.10 Super-Wide Angle Port Body.