The D800 is not the camera you buy for taking selfies, but when I test lighting setups on my own in my improvised home studio, I need a remote shutter release. Cables are annoying, so I bought the Nikon ML-L3 for my Nikon D7000 a while ago. When I got the D800 and searched for the IR mode setting on the release mode dial, I could not find it. Here it is on the Nikon D7000:
Nikon D7000 with Nikon ML-L3 remote shutter release (using internal IR sensor). Note the icon selected on the release mode dial.
After some investigation, it turned out that the D800 does NOT have an internal IR receiver — that’s why there is no button. So in short, the ML-L3 is completely useless for the D800, you need external gear. 😐 So I had to get something else. What I finally settled with is the Pixel RW-221/DC0 Oppilas. You get a sender and a small receiver you can attach to the D800 via the DC0 port. It is € 30 and works pretty well. Note that you do NOT have to attach it to the flash port, you can leave it dangle in case you need the flash port for something else.
Nikon D800 with Pixel RW-221/DC0 Oppilas (sender + external receiver attached to DC0 port)
It supports single exposure, multi expose, bulb and timing modes and the plastic button feels OK after getting used to it. Other companies offer similar stuff in the same price range so check what is available.
It is also notable that you are NOT gonna be able to use the DC0 version with the D7000 since it does not have a DC0 port (you can buy a second cable for cheap though).