Krasnogorsk-3 Super 16 mm viewfinder mask modification (1.33:1 to 1.66:1)

Okay, let's modify the viewfinder for a complete super 16 mm conversion (after the gate and the recentering ring). For this project I used a thin copper plate and a CNC laser cutter to make the new mask (thanks to the jeweler).
MASK MEASURES
Diameter: 18.5 mm
16 mm (original mask): 9.6 mm x 7.2 mm (1.33:1)
Super 16 mm (new mask): 12 mm x 7.2 mm (1.66:1)
#16mm #krasnogorsk #cinematography

[@seansimpson2586]

Can you make a video about repairing the light meter?

[@kevinpowell4044]

Thank you for showing where the K-3 mask lives and how to access and modify it! In the middle of performing Ultra 16 mods on two cameras now to 11.66 mm × 6.15 mm = 1.85 aspect ratio. Is the mask a 1:1 with the actual film gate size?

[@sandrolab]

You're welcome! Actually I did a simple proportional calculation based on the size of the mask and not the gate. So I kept the same height, given that we can consider the viewfinder as a secondary and independent optical system.

[@thousandoaksmall1995]

Cool video, I'd love to see more videos about K3 mods. There's almost no good content on modding these cameras. But the position of the ground glass after a super 16 gate upgrade is then off to one edge. So, while the new mask's shape is 1.66:1, the image in the viewfinder is still not the accurate frame, correct? That is, wouldn't you then need to modify the ground glass' position and shape as well?

[@sandrolab]

Hello, I think is not necessary to modify the ground glass' position. I see that apart from being positioned before the gate and not after, it is also wide enough to cover the projected image. So using an off-center ring should be enough. Correct?

[@thousandoaksmall1995]

@@sandrolab The off-center lens ring does re-align the lens' optical center with the new super16 frame center, which is important for many reasons, but after changing to a super16 gate (recentered lens or not) you're ground glass will now be offset. The re-centered mount doesn't do anything to compensate for the viewfinder, just the film frame. While writing this comment, I put up this Short to demonstrate what I mean. This is my K3 after a super 16 gate and re-centered mount was added, and the viewfinder mask removed entirely. Observe the difference in the shape and position of the viewfinder view (white) versus the actual frame (orange). ruclips.net/user/shorts9UgZqH4Qi_E

[@sandrolab]

I was gearing up to test some film shoots, but you came from the future! Have you already tried changing/modify the ground glass position or found other solutions? Thank you so much for this priceless information.