I needed a way to control composition of a river shot with head above water whilst working with hand-held cameras without donning a wet suit and mask. You can point the camera in about the right direction or ‘eyeball’ the shot and many will work. But I was frustrated by getting too many great compositions with technical errors or sharp pictures with poor composition.
All I needed was a camera live view piped above water, which I’ve done with my remote control rigs, but when the action is less predictable and you’re frequently changing camera angles, you don’t want to be using heavy duty direct feeds to remote laptops. So I wondered whether I could mount a GoPro above my main camera and take a wireless feed from that to an iPhone mounted above the camera and out of the water.
The normal GoPro wifi control system is pretty good, but you lose it at only an inch or so underwater due to the characteristics of radio wave propagation. There was some good info out there on the web for how to overcome this, but my early attempts all failed. Then I stumbled across the critical piece of information. You have to chose which frequency you’ll use (I have options for 2.4 and 5GHz on my phone) and then match your aerial lengths at the iPhone and GoPro ends to match the associated wavelength. In fact you only need to use half wavelength so I chose 2.4GHz as the control frequency and 6.3cm as the half-wavelength size for the aerials.
On test in a deep rain butt it works! I can angle the GoPro and chose a field of view to match the main camera and with only a very short delay (less than half a second), I get the feed of what’s happening underwater to my iPhone above water. It’s more than good enough to frame a shot and get a better look at the action without putting a wetsuit, mask and snorkel on.
The pictures show the set up. You need to use the correct type of co-axial cable (RG 174) and for a 2.4GHz set up you just strip the insulation and shielding back by 6.3cm at each end to create the aerials. There’s no need to remove the inner plastic shielding. Other blogs recommend gaffer tape to secure the aerials at each end, which works, but I used some small perspex blocks that I drilled to fit the cable and then chemically welded them to the GoPro. From my school science days, I recall that Perspex has dielectric properties, so I thought it might help the wifi transmission by keeping the path contiguous rather than just close by.
I’m not too keen to drop my phone in the water, so I use a sturdy grip re-purposed from my drone control unit, to which I’ve added a small mounting block for the aerial. Field trials early next week if the weather holds. I’ll share some results. I think the beauty of this system if it works is that I will be able to use it on a pole cam or any other device that I wish to use for underwater photography.
Happy shooting!
Update: I’ve done a field trial and it was largely successful. Great to get a feed from underwater and so put more accuracy into the composition. As always, there were things to iron out. The balance was wrong and the rig slightly unstable as a result. I’ve re-engineered the supports but also done a trial with a small tablet to take advantage of a bigger screen (see photo). It works a treat!
The Riverman 