Mamiya Six Folding Camera Lens Transplant

This blog post describes the process of me removing a Olympus D-Zuiko 75mm F3.5 lens from an Mamiya Six Automat to a Mamiya Six non Automat camera fitted with a Setagaya Koki Sekor 75mm F3.5 lens.

I bought a Mamiya Six "repair or spare" camera from Japan.  The shutter was damaged beyond repair.  A pity as it is a good camera.  A while later, I bought another Mamiya Six camera, a Mamiya Six Automat version.  It was quite cheap.  The Automat camera was strictly a spares camera.  It has a number of missing parts, but the lens was attached.  When it was received, I found the shutter was working well and the lens was in good condition.

Broken shutter removed from camera

Shutter jamed and I could not unjam it

I decided to swap the lenses to make one working camera.  The original camera has a Setagaya Koki Sekor 75mm F3.5 lens with a Copal shutter which goes up to 1/300s.  While the Automat camera has a Olympus D-Zuiko 75mm F3.5 lens with a shutter which goes up to 1/500s.  When I removed the lenses from the cameras, I found they have different location pin positions.  The swap was not as straight forward as I thought.  I will have drill a new hole for new locating pin.

Cocking ring return spring as I removed the lens from lens board

Lens and shutter removed from camera

Front lens element unscrewed showing the cocking ring

The cocking ring has hook point to the front.  This hooks onto a lever on the camera which cocks the shutter.  It also has a return spring at the bottom.  I will have to somehow attach this spring onto my camera.  I also have to cut the cocking ring hook off, as it catches a spring on the non Automat camera

Ring removed with hook pointing up

Hook cut off and edges smoothed

Cocking ring back on the lens

Then I had to drill a new hole to the lens board for the new locating pin to fit onto.

A new 2mm hole drilled to allow Olympus Automat Lens to fit

On the Automat lens, there were two paper spacers and one metal spacer fitted.  When I tried to fit all the spacers onto the new camera, it was too thick and there was not enough thread for the locking ring  to screw onto.  In the end, I did not fit the metal spacer and the lens fitted.

For the return spring, I made a small metal bracket with a small hole drilled into it.  I then glued this small bracket onto the lens mounting board.  The tricky part was to attached the spring.  It took me a little while but manged it in the end.  Now, the cocking plate now returns after cocking the shutter.

The last step was to calibrate the rangefinder.  This was achived with a small piece of ground glass attached to the film plane, set the shutter to B, focus to infinity and check the image on the ground glass is sharp.  Luckily for me, it was and I did not have to add or remove any shims.

Now, the camera is all set and ready to shoot.

Lens & shutter on the camera

Note the return cocking ring return spring on bottom right of the lens

Camera ready to shoot