Peak Design Cuff
Wrist strap
Peak Design Cuff
Wrist strap
The manufacturer states that the anchor links can hold up to 90 kg, which is the impression they give when you hold them in your hand. I see no reason why it could not be used with a D800. In any case, this hand strap is well thought out and the whole system is very flexible. I don't think there is anything equivalent on the market.
Yes, it didn't take me a minute. Pull the loop all the way through the holder on the Sony and then thread the red, round button of the cuff through the loop and tighten it.
Yes, it contains leather accents (genuine leather) according to the manufacturer's website.