This focus gear enables manual focus adjustment for the Canon EF 8-15mm f/4L Fisheye USM lens via the Athena Optical Dome Port OPD-FZ200MF when used with Sea&Sea MDX-series or Nauticam dSLR housings.
The focus gear is useful in the following situations:
* When you shoot fast moving subjects, like dolphins under limited ambient light (dark environment), so auto focus does not function effectively.
* When you shoot “half-in half-out” photos and would like to manually adjust focus on subjects on land and underwater.
* The focus gear can be used in conjunction with the zoom gear (for Sea&Sea product #31154 / for Nauticam product #19537).
