Just a Photographer wrote:
I did this past weekend....3D and then 3D Auto...
Was really hit or miss for complicated wedding/evening photography, It was easier to go back to AF-C/51 for me.
I'll wonder what that complicated shot was...
Was the bride so afraid of you and your camera that she ran away?
Really I don't see any use of the 3D autofocus feature unless for fast moving objects like in sports or birds in flight.
The only time I've used the 3DAuto on my camera was for an athletics meeting where I was situated at the finish line and was panning specific athletes down the 'home straight' and across the line. It worked well for this situation, and since then I've never used it again.