That video is of the Hero 2. We're talking about Hero 3+. The lag was much improved in the newest version, and especially in the Black Edition. I've tested it with an older Samsung Galaxy S2 and the lag on the iphone is the smallest. Tested it with other devices as well, only processor power seems to matter.T0Rtur3 said:Edit: Found that video, here it is. http://youtu.be/Cn35pgrPZ8E
Also, the phone I'm using is a Motorola Droid Razr M. So not exactly a beast in terms of hardware, and like I said I get very low lag.
I think lag in close proximity doesn't tell you anything. Once you get your Gopro mounted on the gimbal and lift your bird in the air, everything changes: the wifi signal is much weaker compared to the FC40 camera. I think the most important is the signal degradation by the metal in the gimbal, which basically touches the wifi antena of the GoPro. And, since the signal is very weak, I would think the devices automatically swich to lower speeds, thus further increasing lag. Up in the air, on the connection limit, the lag is at least 2 secs, thus making impossible to fly FPV safely.
As I said in the beginning, for a GoPro, the wifi connection is only useful for framing the shot. If you really want to fly FPV, you'll need a separate FPV system, either one that takes video from the GoPro output, or one with a second dedicated FPV camera. More seasoned flyers will recommend the latter, because with a fixed (non-gimballed) camera, you can see the copter pitch.