Methods to adapt Sekor Z and M39-M65 lenses to the RB67

The RB67 lenses are excellent, however better and cheaper lenses are available for specific purposes.

I'd like to share a few methods to adapt Sekor Z (RZ67) lenses, M39-M65 enlarger and industrial lenses, and others, to the RB67--with significant caveats and limitations.

This is the first of hopefully a series of guides on the topic: https://zv.io/blog/rb67-with-rz67-and-m42-lenses/

I hope this inspires others to experiment with similar techniques and realize their artistic visions more easily.

As an update, a new M65 adapter is now commercially available: https://zv.io/blog/rb67-with-m65-lenses/

Thanks for writing this up. It is an interesting idea, that if you remove the optics from an RB67 lens (and there are a fair number of relatively inexpensive RB67 lenses around), you have a shutter and possibly aperture that can be used with other things, and the camera provides a large amount of focus travel. One could mount a meniscus lens for retro landscape and portrait photography, for example.

One caveat - the inner 42mm mounting thread isn't the M42x1 familiar from Pentax-screwmount. I removed the optics from an RB67 180/4.5 lens - this lens is easy because the optics are a single block in front of the shutter, with nothing behind. This exposes the front mounting thread of a Seiko #1 shutter. This thread is actually M42x0.75mm pitch, not M42x1. Similar Seiko #1 shutters are used in a few lenses for large format and also have a M42x0.75 thread for the front cell (and rear) in that application. I don't know what thread the RZ67 shutter uses.

So I don't think one could screw in an M42 lens directly without boogering the threads, but T-mount is M42x0.75 so a reverse T-mount adapter could work. Also filter threads are typically 0.75mm pitch, so one might be able to find a 42mm to something step-up ring that was usable.

Another update, testing this with real film works exceptionally well: https://zv.io/blog/rb67-macro-madness/