The whole day was challenging light, clear day with bright high noon sun. So I choose to shoot in the shade of the trees. The river upstream of the bridge was a mix of bright light through the trees and shade. Example photos taken with and without a reference perspective.
The subject is the shallow rocks capturing leaves and needles. The photo needs perspective. Reference perspective: notice the riverbank grass alongside the top photo. Without the grass the subject has no clear size. A person knows its pine needles and leaves on a rock in a river. But without the grassy bank its unclear as to how large the river is, how shallow or deep the water goes. Just how big is that rock anyways. The bank fills in all the questions.
Early on my moving water photos I zoomed in on the rocks, close up shots of water racing past and the blurred motion. Intersesting to see in person but tranlates poorly without a reference. Perspective requires something familiar and sationary to tell the full story. Experience taught me to include something familiar: riverbank, shoreline, tree or trees, a person, a building or a bridge. Without something familiar a river's size is unclear.