Overview

This kit converts Mamiya Sekor-C lenses with a native Mamiya Sekor-C 645 mount to a fixed Arri PL mount.  This conversion is non-destructive, meaning it can be reversed at any time.  The mount kit is designed to fit over the original mount.  The only thing that needs to be removed from the original lens is the three original mount screws.  This kit is not compatible with RZ Mount Sekor lenses.

Installation requires basic mechanical aptitude and only involves a few screws.  Our mount kits are designed and manufactured with very high tolerances in order to maintain accurate flange focal distance.  It is worth noting that optimal infinity performance from the lens can be achieved by adjusting the flange distance to within 0.0005” (12 microns).  This is partially dependent on the condition of the lens when it is being converted.

Kit Includes: PL Flange, Sub-mount, x3 M1.7 screws, x7 M2 screws
Tools Needed: #0 and #00 phillips JIS screw driver
Time Required: 20 minutes per lens.

Installation

In this example, we are modifying a Mamiya 35mm f/3.5 from its native 645 mount to a cinema standard Arri PL mount.  The process is similar if not identical across all Mamiya 645 lenses.

Start by removing the three phillips head screws from the original Mamiya 645 mount.  This will separate the original mount from the lens.  Excess glue from the original mount may hold the mount in place.  It is important that the placement of the original mount not be disrupted, as that may affect internal iris mechanisms.

Align the sub-mount so the “Duclos Lenses” engraving is in line with the witness line on the lens.  “Duclos Lenses” should be at the top of the lens, when mounted on the camera.

Use the three included M1.7 screws to secure the sub-mount to the lens.  In very rare instances, the lens may have a different hole pattern than is seen on the rear of the sub-mount.  If that is the case, please contact us.

With the sub-mount installed, we can now install the PL mount.  The PL mount is held on by 7 screws, meaning that one of the eight “ears” on the mount does not have a corresponding thru hole for a screw.  Locate this ear and align it to the lower left corner of the sub-mount (8 o’clock, in clock terms).  Place the PL mount over the Sub-mount, and use the 7 screws to secure the mount to the sub-mount.  If any screws are left over, the mount is not properly aligned, and will need to be adjusted.

DISCLAIMER

Duclos Lenses is not responsible for any damage caused during disassembly, installation, or reassembly. Mount installation and calibration is offered free of charge for all mounts purchased from Duclos Lenses. If you're not comfortable performing DIY mount installation, we're happy to help you. Don't hesitate to reach out to us via email, webchat, or phone anytime.