Blurry sport pictures are the result of two possible causes. The blur could be caused by the lens being out of focus or what is known as motion blur. Motion blur is a result of trying to take a picture of a moving subject using a shutter speed that is too slow to capture and freeze the action. With a little preparation you can take sport photos with your Canon 5D that will be in focus and not blurry.
Turn on the Canon 5D with the power switch on the back of the camera. Rotate the exposure mode dial on the top-left of the camera to the "M" position. This places the camera into Manual mode and will give you complete control over the camera.
Turn the front dial by the shutter release to adjust the shutter speed to a minimum setting of 1/250 of a second. Depending on the type of sport, this shutter speed will freeze the action; however, you may need a faster setting if you are shooting a very fast moving sport.
Turn the rear dial on the Canon 5D to set the aperture of the lens to the lowest number. This will open the lens to its maximum opening, allowing the most light into the camera.
Hold the camera to your eye and press the shutter halfway down. Observe the numbers in the bottom of the viewfinder. If they are blinking your picture is underexposed and you will need to adjust your ISO (light sensitivity) setting. If the numbers are not blinking, you have enough light to take the picture.
Press the ISO button on the top-right of the camera and adjust the ISO setting higher until the exposure numbers stop blinking. Only adjust the ISO to the setting you need. Higher ISO settings create more digital noise in your pictures.
Press the "AF" button on the top-right of the Canon 5D and turn the rear dial and change the focusing program to "AI Servo." This setting will track the moving subject when you have the shutter release pressed halfway down. It will give you a picture that is in focus and will use a lot of battery power compared to if you're continually adjusting the lens.
Hold the camera to your eye, compose your picture, press the shutter release halfway down to activate the focusing program, follow the moving subject and press the shutter release all the way down to take the picture when you want.