• Front side - 70mm OD and clamp to fit Vazen Variable Diopter (Kowa 16-H version)
• Rear side - M68x0.75 female thread

Important note: Only use this with the KOWA 16-H version of the Vazen Variable Diopter. The ISCO ULTRASTAR version of the VVD WILL NOT WORK.

The purpose of this kit is to minimise the air gap between the Vazen Variable Diopter and the Kowa 16-H, maximising field of view and minimising vignette. It also provides a more secure mounting solution.

There are two parts in this kit: a threaded ring (DC_inner) and a clamp ring (DC_outer). You will need your own Vazen Variable Diopter (VVD) and Kowa 16-H.

Installation instructions (please refer to the pictures):

1. Calibrate your Kowa to infinity focus and secure the focus ring with tape as shown.
2. Loosen the three lock screws on the front ring of your Kowa, then unthread the front ring, taking care not to affect your focus setting.
3. Fully thread DC_inner onto the front of the Kowa, then secure using the lock screw on DC_inner. Do not overtighten, it just needs to stop DC_inner from unthreading. If you need to adjust infinity later, you will need to unthread DC_inner slightly to allow the focus ring to turn.
4. Take note of the three notches on one edge of DC_outer. Slide DC_outer onto the rear ring of your VVD, making sure the three screws sit in the three notches. Tighten each of the six clamp screws gradually and evenly. Do not overtighten. Optional: for extra security, you can drill shallow divots in the VVD’s rear ring so the screws can grip better.
5. Slide the front of DC_inner and your Kowa into DC_outer and the rear of the VVD as shown. Tighten each of the six clamp screws gradually and evenly. Do not overtighten. Ideally, avoid positioning a screw directly on DC_inner’s lock screw. This is the step where you set the position of your VVD’s focus markings.

Known compatible lenses:

• Kowa 16-H
• Kowa 8-Z
• Elmoscope II