Simmod EF Lens to L-Mount Body Positive-Lock Adapter

Canon EF lenses were designed around a spring-tension mount.

L-mount systems require a more rigid interface under load.
This adapter replaces that interface with a controlled locking system.

The Simmod EF to L-Mount Positive-Lock Adapter is a precision-machined adapter that enables Canon EF-mount lenses to be mounted onto L-mount camera systems, while introducing a positive-locking mechanism to improve mechanical stability and alignment.

Positive-Lock Mount Interface

This system replaces the traditional EF spring tension with a stainless steel locking collar.

• The lens is inserted and mechanically clamped into position
• Torque is distributed evenly around the mount
• Rotational play and micro-movement are minimized

Unlike friction-based adapters, this system creates a fixed, locked interface designed for use with follow focus systems and rigged setups. (simmod)

Compatibility

• Lens mount: Canon EF
• Camera mount: L-Mount (Leica, Panasonic, Sigma) (B&H Photo Video)

Compatible systems include:

• Leica SL series
• Panasonic LUMIX S series
• Sigma FP series
• Blackmagic L-mount cameras (B&H Photo Video)

No electronic communication is supported.
This is a fully mechanical adapter.

Construction

• Body constructed from high-grade aluminum
• Stainless steel locking ring
• Internal anti-reflective coating to reduce stray light (simmod)

Manufactured using CNC machining to maintain consistent tolerances and alignment.

Mechanical Performance

• Maintains accurate flange focal distance for EF to L conversion
• Supports infinity focus
• Designed for zero-play engagement under load
• Optional shim adjustment for fine calibration (simmod)

Typical tolerance is approximately 0.005mm, supporting precise optical alignment. (simmod)

Support and Mounting

• Integrated support foot
• Includes:
  • 1/4"-20 thread
  • 3/8"-16 thread

Allows mounting to rods or tripod systems to reduce stress on the camera mount. (B&H Photo Video)

System Behavior

• Converts EF lenses to operate on L-mount bodies
• Provides a rigid, locked mechanical interface
• Eliminates lens rotation during operation
• Does not support autofocus or electronic control

Notes

• Designed for manual or cine-modified EF lenses
• Positive-lock mechanism functions similarly to PL-style mounting
• Adapter remains passive with no electronic passthrough

A mechanical adapter designed to convert Canon EF lenses to L-mount systems using a positive-locking interface to reduce play and maintain alignment under load.