Sea&Sea Extension Ring 46 with Focus Knob

Extension Ring 46 with Focus Knob, provides manual focus for compatible zoom lenses. (Extension ring equipped with port lock).

Compatible Housings:

• MDX series housings.

Compatible Lenses: (as of June2014)

• Canon EF 16-35mm F2.8L ll USM
• Canon EF17-40mm F4L USM
• Nikno AF-S Nikkor 18-35mm F/3.5-4.5G ED
• Nikon AF-S Nikkor 16-35mm F/4G ED VR

* Compatible FC focus gear required for manual focusing (can be used in conjunction with a compatible zoom gear).

* Until now, auto focus has been the only option available when using a zoom gear. With the new Extension Ring 46 with Focus Knob, you can now manually focus a compatible zoom lens. When your camera's AF frames do not cover your subject, you can manually focus a compatible lens without changing composition.
* This product is the ideal solution when you shoot fast-moving subjects (which even the latest auto focus may not follow) or when you shoot in dark environments and when there are lots of particles suspended in the water; all situations where auto focus will not function correctly.
* The focus knob is located in an ideal position and angle to be easily operated with the index finger and thumb.