Optical system comprising a motor, an optical element, an optical detector, and a linkage that connects operation of the motor to movement of the optical element and the optical detector relative to one another. The linkage may include a shaft and a drive element that operatively connects the shaft to another part of the linkage. In some embodiments, the drive element may include a clamp having a base and a retainer that compressively secure the drive element to the shaft by engagement of a cylindrical surface region of the shaft with the base and engagement of a flat surface region of the shaft with the retainer. In some embodiments, the drive element may include a collar secured to the shaft with a fastener disposed in threaded engagement with a transverse hole defined by the shaft.