If the taking lens go wider, the vignette becomes serious issue. To solve this issue, we must place the anamorphic lens as close as possible to taking lens.

Parts list

Rapido V3 Clamp

• https://www.rapidotechnology.com/

Redstan Classic Original Custom Anamorphic Lens Clamp

EDIT: This is not the “Classic Original Anamorphic Lens Clamp”. Thanks to stan for pointing out on this blog. And thanks to Mikkel Bøje for pointing out on youtube.

I asked the original owner of this clamp about the exact name, and he said: “I sent him(Redstan) pictures of the Kowa and he simply said he had what I needed and referenced it as a ‘2 part adaptor in black'”. So if the others like me try to buy the same thing, it’s better to tell Redstan our requirements first before buying.
It should have

• The 52mm inner thread for Kowa 8z/16h.
• The 55mm outer thread.

But as commented below, Redstan makes different and better clamps these days. I just want to share the idea.

Stepdown ring: 67mm to 55mm

3d printed shim ring (detailed below)

Structure of the Rapido V3 Clamp

Confirm the structure of the Rapido V3 Clamp, the gap between Inner Ring and Rear 77mm Adapter is narrow enough. The paper cannot slip into the gap.

Combine the Rapido V3 Clamp and the Redstan

Combining the Rapido V3 Clamp and the Redstan’s inner part (M55 threaded) with a step-down ring, the anamorphic lens could not be tightened.

Tightened with 3d printed shim ring

To be tightened securely, I need to insert something like a shim ring between the Redstan’s inner part and the step-down ring.

The measured size is the following:

• thickness: 10.5ｍｍ
• Inner diameter: 55.5ｍｍ

There’s no size in the market, so I designed the 3d model and printed by 3d printer.

Rapido V3 Clamp Shim Ring

3d model on Thingiverse.

How to Assemble the Rapido V3 Clamp Shim Ring

Final Shape

Rapid Technology V3 Clamp could be found here:
https://www.rapidotechnology.com

Customizable Slip-On Lens Cap

Here is the Thingiverse customizer based on this model.
Fully Customizable Slip-On Lens Cap