Hopi Point, Grand Canyon National Park
Image: 5D Mk III, EF 70-200 f/4, 81mm, f/11, 1/20 sec, tripod.
I have found that I need to shoot at at least 1/500 of a second and use very good technique in order to get a print quality image hand held. A tripod is a must for conditions that are not very bright, even image stabilization is not enough to get a tack sharp image hand held in low light. The upper image can be printed at probably 24 inches (hand held at 1/250 sec), while the lower image can probably be printed at 36 inches (tripod at 1/20 sec).
Some times an image can be shot sharper hand held, I shot the upper image hand held and on a tripod, the wind was blowing at about 20 mph and it was obvious to me that shooting on a tripod was not working out so well, so I switched to a larger aperture, hand held and got the faster shutter speed and also took the wind blown tripod out of the equation. Later when the wind died down I was able to shoot back on my tripod and get sharp images.