The Pha Charoen Waterfall (pronounced "PAH chah-RDOHN" [note the "r" is rolled]) was a lovely 97-level stair-stepping waterfall that was really photo friendly thanks to its combination of texture, size, and jungle setting. Needless to say, we really enjoyed photographing it with a tripod when the timing was right, which I'll explain below.
Julie and I noticed that it was a fairly popular spot with the locals, and it was pretty easy to explore given that it was well-signed and had a very developed walkway to the viewing area at its base. But I guess it was its apparent popularity that did present photo challenges as many people would try to walk partway up the waterfall (right in front of the camera I might add) and linger in its cool waters.
It was possible that our visit coincided with a time when many Thais were on holiday, which might have amped up our perception of its popularity, but in general, the best time to photograph the falls would have to be early in the morning before the crowds arrive and before the sun would start creating bright and dark zones.