I shoot this way a lot when I'm trying to stabilize a long lens without a tripod and lower my point of view at the same time. Getting the elbow set firmly against the leg seems to help with stability. The next step is to get down right on my belly and put the lens mounting foot on the ground, or on my hand on the ground. But this position usually works and is faster to get into and back out of if I need to move closer. The Paramo ground tyrant shots in this gallery were taken like this, actually I was shooting it while Melanie snapped this image. I didn't know she had turned her camera at me.