Note: In general situation, there is no need to adjust the shims after changing the mount. If you still need to adjust the flange back distance, Please refer to "Flange Back Adjustment" for operation..
Step One: Rotate the Lock Ring 90 degrees anticlockwise till the Ring cannot be rotated anymore.
Step Two: Press Lock Button, rotate the mount (silver part) anticlockwise and in the meantime pull out the mount.
Step One: Please make sure that the Lock Lever Socket is at the top left side
(see in the picture).
Step Two: Align the breach under the mount to the embossed screw on the mount plane, lay down the mount.
Step Three: Press the Lock Button and rotate clockwise till hear a sound of "clatter".
Step Four: Rotate the Lock Ring clockwise to the top. The mount is locked.
Hold the handle of the rear filter and you can pull in or out the filter.