Must be infront of the camera as well. Using it behind the view finder will likely not work.
Glenn, it will work behind with the 5100, it has 2 sensors, one front and one rear. (I have one and have used it both ways)
Pat in NH
Thanks for the correction Pat. I have the D80 and D7000 and unfortunately, the remote only works if you are infront of the camera. Good to know.
It it a genuine Nikon remote, there are lots of fakes and they give out a weaker IR light.
Must be infront of the camera as well. Using it behind the view finder will likely not work.