T&E Run wrote in post #8770835
...... I usually try to get at least 2 or 3 stops above the focal length (example= @400mm I try to be at least 500 or 640). Is this enough to get tack sharp shots of sports. My photos are never tack sharp, sharp enough for me, but they could be better. Thanks for any input.
If you are talking about your 40D, then @400mm (the lens's nominal value) 500 or 640 shutter speed will be very minimal given that the 40D has a crop factor of 1.6. At 300mm length I try to stay above 1000 shutter speed. As far as your pictures not being tack sharp, you could be dealing with motion blur or the 40D's anti-aliasing filter that makes the shots straight out of the camera somewhat soft; therefore, requiring sharpening in post processing, unless you bump the in-camera sharpness.
As sample or two would help the experts around here give you a better idea on what is going on.