He was primarily a painter. But as a photographer he brilliantly grappled with aesthetic tension between a three dimensional world and a two-dimensional plane in the print - an important theme in the 1920's Constructivism. Carlton Watkins was even more prescient in certain images, by
decades, so is also regarded as one of the predecessors of Modernism in photography, with both producing works beyond their mere historic interest
to us today. Take your time with these images and you might understand what I mean. For example, is the image posted above, from that link, intended as a two-dimensional picture, or does it hold a kind of subtle tension inviting you, at the same time, into a three dimensional world. It's
the ambiguity itself that evidences his genius. Any fool with a wide-angle lens could have bagged the nominal subject if here were there; but it wouldn't elicit the same effect.