I just picked up a Nikon 16-35mm today. While playing with it around the house i noticed that i would back button focus on something like always and then let go to lock it. maybe a second or 2 after letting go i hear a faint click and the picture in the view finder moves the very smallest bit down. I also hear a noise when keeping the focus down. I wouldnt call it a hum but when you put it up to your ear it sounds like its on like powers running through it. I does NOT happen in live mode. I then turned off the VR and the noise and click and everything went away and it works fine. It never loses focus, ive just never had a lens make a clicking noise a second after letting go of the focus or have a hum like powers going through it.
I am brand new to this lens and well fx lens in general, Is this normal?