Digital Camera Shutter Speed & Camera Movement

Before an object in movement, the shorter the exposure time, the shorter the trajectory of the image on the film, and therefore less movement is registered. If the displacement of the image of a body in motion is not seen on the film (the lines it traces are reduced to points as consequence of a fast shutter speed), the aspect of the image is completely static and detailed, and we say the movement has been "frozen". Between this and total blurriness there are intermediate possibilities that, incorporating a certain amount of movement in the image, provide a good amount of information about the object in movement.

Shutter speed is necessary to freeze a movement depending on it's angular velocity; also, the choice of shutter speed depends on the aspect we want the image to have.

There is an alternate way to stop movement, which consists of following the object in the frame while we shoot ( sweeping ). This diminishes or cancels movement of the object in the frame, but in change causes blurriness of the background. With this technique, as long as we're able to keep the object in the same position in the frame, we wont have to use such high speeds as when the camera stays still.

Camera Movement
Uncontrolled camera movement during exposure causes completely blurry pictures. It's necessary to ensure the stability o the camera during exposure by holding it firmly but not rigidly; absolute camera stability in your hands is impossible; any vibration in the camera is registered with speeds under 30. Below this speed it's necessary to use a sturdy support. With a tripod any possibility of movement at any speed is eliminated. During long exposures you have to remember that any object in movement during exposure will be registered as lines in a static background (i.e. car lights in night pictures). Any risk of accidental vibration in the camera during exposure is greater with the smaller the angle the lens covers (7.2.2).