Siriotub-Style Lensmount/board for Durst Enlargers

Siriotub-Style Lens Board for Durst Enlargers (M605, M601, Laborator 1200)

A 3D-printed lens mounting plate designed as a drop-in replacement for the original Siriotub, following its exact dimensions.

Specs:

• 78 mm outer diameter
• M39 × 1/26" thread (standard Leica thread mount)

The thread fits snugly but not too tight — tested and working well with both a 50 mm f/1.8 and an 80 mm f/4 Rodagon lens.

Why I made this: The 80 mm Rodagon is the sharper lens, but requires more distance to the paper and less distance to the negative Carrier — this board makes it possible to print larger formats that weren't achievable before. Also i wanted to print larger Papers without projecting on the floor or wall, which is both a hustle and inconvenient. 

Notes on the 25 mm version: The deeper recess keeps the lens well clear of the negative carrier, so no contact issues there. The trade-off is that reading the aperture ring becomes a bit awkward since the lens sits much deeper inside the mounting plate than usual. If you look in the gap a little closer, you can see it anyway.

I haven't been able to test whether mounting the lens closer to the carrier introduces any optical distortion to my untrained Eye it seems fine though. If you have experience with this, I'd love to hear from you in the comments.

Hope this saves someone the search for an original Siriotub!