Focusing E-Mount Adapter for Ultrafast Lenses
Old ultrafast lenses — often f/0.75 to f/1.6, with no iris and no focus mechanism, mounted only by a giant external screw thread — normally can't focus at all on a mirrorless body. This adapter lets the lens screw straight into the mount and focus by partially unscrewing it. The 60mm-thread version fits lenses like a Kowa 55mm f/1 or 42mm f/0.75; the 80mm-thread version fits larger lenses like a Rodenstock XR-Heligon 95mm f/1.3, and uses a different internal profile since that lens's huge rear element would otherwise vignette. Both flanges are sized to fit older and newer Sony E-mount bodies (tested on a NEX-5 and A7 II).
What you'll need
- 3D printer
- Sony E-mount camera body
- An ultrafast lens with a large external screw thread matching the 60mm or 80mm adapter
Suggested material: PLA. The large flat on the adapter makes the E-mount lens-release button a little harder to reach, and the 80mm version just barely clears the grip on a NEX-5 — a tradeoff of keeping the lens close enough to the sensor for a usable focus range.
Design by profhankd, originally published on Thingiverse. Shared here unmodified under CC BY 4.0.