The 150mm f/3.8 N/L is optically identical to the 150mm f/3.5 lens, with the addition of an internal leaf shutter, for flash synchronization up to 1/5

The 150mm f/3.8 N/L is optically identical to the 150mm f/3.5 lens, with the addition of an internal leaf shutter, for flash synchronization up to 1/500 second for outdoor fill-flash. The internal leaf shutter reduces the maximum aperture slightly to f/3.8. It features manual operation or motorized leaf shutter cocking with the 645 Power Drive Grip WG401.