SAND DUNE, people. Sloping. Uneven.
Here's a shot from DC where the guys are standing on solid ground.
I have yet to meet a man six feet tall who has height issues.
And he is taller than Trinneer, so even the PR people would have no reason to complain.
I remember a concerted effort to make the Big Three of TOS look more the same height. A challenge, since Shatner was 5'9", Kelley 5'10", and Nimoy just over 6 feet. They did it with different-height boot heels. Shatner had at least a couple of inches of heel, Nimoy practically wore flats.
Hey! What happened to Trip and T'Pol?