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Video B4 (2/3" and 1/2") lens to Micro four-thirds mount adapters

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3D model description

This is a two part adapter that bolts on to the existing B4 flange on the lens and provides a parfocal mount to M4/3rds (Lumix, BMPCC etc).
It is not intended to support a B4 lens via the M4/3 mount !!! (they are mostly too heavy), however, the adapter will easily support small DSLRs via the lens.
The clamp requires 6 off M2.5x12mm screw/bolts and lock nuts for the captive nut recesses.
When clamped together the two parts ensure a tight grip on the B4 flange, do not overtighten; a small gap has deliberately been left so you can adjust the pressure around the mount (any over tightening will be apparent by squashing the gap).
Parfocal adjustment is assumed to be on the lens (eg Canon J9ax5.2B4, Canon J15ax8B4 etc -where there is 1mm of adjustment), this adapter should put the lens in the centre of the 1mm adjustment range.

NEW: Includes adapter for ½" video lenses (eg Canon H15sx6). These use a similar "B4" bayonet, but the flange distance is 12.26mm shorter. ½" bayonet flanges can be recognised by their slightly larger (3.4mm dia) locking pin.
NEW-2: adapter to use B4 lenses on ½" bodies (untested, but should work as requested...)

3D printing settings

FDM prints: The clamp part should be printed, with support, with the captive nut cage on the build plate (this should ensure a smooth surface against the lens' B4 flange). The M43 mount/B4 adapter can be printed with the M43 mount on top and without support, though, in Cura I find "with support" works fine and gives a slightly better M43 flange. (Ensure the recess for the B4 flange is free of print material and flat against the mount). The 'barrel' section of the adapter does not require support.
The 1/2" adapter has also sucessfully been printed in SLS, PA12 Nylon.

3D printer file information

  • 3D design format: STL Folder details Close
    • B4-M43(v2.2)CLAMP.stl
    • B4-M43(v3)BARREL.stl
    • B4-halfinchB4 adapter(v1).stl
    • B4.5inch-M43(v3)BARRELv1.stl

    Learn more about the formats

  • Last update: 2022-02-02 at 11:36
  • Publication date: 2018-01-05 at 15:21


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