My D5100 has infared ports both fore and aft. I bought the wireless on Amazon for $13. It is great.
randym77 wrote:
I have both.
The wired is more expensive. There are cheap knockoffs, but IME, they aren't worth it. If you do night photography, or use an infrared filter, the cable release is absolutely necessary. You can use it to do very long exposures, and also things like time-lapse.
The wireless are much cheaper. They are meant to be used from in front of the camera. I only use it when I want to be in the photo. Otherwise, the cable release is better.