Good points all ... thanks for the insights. I shoot with a D7000 and sometimes when I get a soft focus in a portrait shot I would blame it on missed focusing. But perhaps I should be pushing that shutter speed up some and open the aperture a bit more instead of the other direction. I do have a question about how to account for the 1.5 DX factor for the shutter speed rule. Should I use the focal length as indicated on the lens or should I multiply this by 1.5 to get the equivalent full frame focal length when shooting with a DX camera and an FX lens? When I shoot sports I always shoot with my shutter speed at 1/800s or faster. The longest lens combination I have is a 1.4 tele with the 70-200mm 2.8 VRII. So my max focal length in 35mm terms would be 1.5x1.4x200 which is 420mm. Using your rule of shutter speed minimum as 1.5 the focal length gives me 1/630s in full frame terms. So the setting I have found by experience that works best when shooting sports handheld is consistent with your rule. Of course the other obvious reason to use 1/800s or faster when shooting sports is because my subjects are moving. I now wonder, however, how much blur is caused by handholding the camera versus subject movement. Does anyone know how to calculate a subject movement speed (say traversing from side to side) which leads to subject motion blur? I can images that there are several factors involved but is there a general rule of thumb here too? Probably academic I know, since from a practical rule I find that I need 1/800s for the kind of sports I shoot ... but I wonder if I might be able to slow the shutter down some if I used a tripod or monopod. I can often use the extra light.