I tried out the first version of the eyefi card many years ago. It was fun the few times I, slowly, got a picture from the camera to the iPad. Did not use it much.
Now I recently started looking at the F-stoppers DVD about interior/architecture photography and they mention they use real tethering (with camera control) on the iPad via CamRanger usb-dongle connected to the camera. Reading up on that I see that the hardware is from 2013.
So my question is now: what is the best way to tether a D800 to an iPad today?
Are you married to using an iPad? The next best way is to connect an external monitor via HDMI.
Personally I would use a laptop (in my case macbook pro fully maxed)
I have tried using my MBP a couple of times, for studio portraits and product shots. It works quite well.
But I'm thinking with an iPad it would feel less of a hassle and something I would do more often. Maybe even be a reason to save up for an iPad Pro :-)
16mm f/2.8 Fisheye AIS, 18mm f/3.5 AIS, 24mm f/2.8 AIS, 28mm f/2.8 AI, 28mm f/3.5 and 35mm f/2.8 UW-Nikkors, 35mm f/2.8 AIS, 50mm f/1.4 non-AI (AI’d), 55mm f/2.8 AIS Micro w/ PK-13, 85mm f/1.4 AIS, 80-200 f/4 AIS, 105mm f/1.8 AIS, 180mm f/2.8 ED AIS, 300mm f/2.8 ED-IF AIS, 600mm f/4 ED-IF AIS, TC14B and TC300.
Hasselblad 500CM with PM90 prism finder and A12/A16 backs, 40mm f/4 CF, 60mm f/3.5 CF, 80mm f/2.8 C, 150mm f/4 C and 250mm f/5.6 C lenses