Nikon D750 remote release cable MC-DC2 allows you to take pictures from a distance. The button duplicates the shutter release and can be half-pressed to focus. There is a sliding lock on the button to lock it for extended exposures. The remote is required for exposures longer than 30 seconds. The remote includes a 3-foot cord (1 meter length). The remote operates without a battery and does not need infrared signal so you can activate it from behind, beside or in front of the D750.
Nikon part number 25395