Really Right Stuff B2-LMT
Lens Mount for B150-B rail. The integrated clamp in the B150 focusing rail is oriented for use with camera bodies (plates that slide left/right), not lenses (plates that slide fore/aft). So we created a new adapter plate called the LMT, "Lens Mount." Mount your lens directly to the LMT, or add our B2-FAB mini-clamp if your lens already has an RRS-style lens plate (B2-FAB not included; purchase separately).
The LMT is the perfect solution for photographers who want to use the RRS focusing rails with collared lenses, the LMT base slides right into the clamp of the focusing rail and has two scales laser etched on both the front (scale etched on the front from 0 in the center to 60mm on each far edge) and the rear (rear of the LMT scale etched from 0 to 120mm) for precise positioning.
The LMT's height provides clearance so that any camera can be rotated to vertical while mounted. The LMT is beautifully relieved to reduce mass and is very lightweight.