Collimating with an end cap fiber cable is no different than with a standard fiber cable. However, the focus position might vary a little (<200 µm) when swapping a standard fiber cable for a fiber cable with end cap.
The eccentric key 60EX-4 is used to adjust the focus position. In some cases the stroke is not large enough. Please use the eccentric key 60EX-5 with a larger stroke instead.