Low shutter speed blurs motion on film. Great for expressing the flow of water, cars, or other objects moving by. Shutter exposure exposed Inside a typical SLR, focal plane shutters employing front and rear shutter curtains are positioned close to the lens focal plane, just in front of the film. Pressing the shutter release button releases the focal plane shutter. Then, the front curtain begins to travel just in front of the film inside the aperture, and after a preset period of time, the rear curtain follows.
Light passes through the gap or slit between the two shutter curtains to expose the film.
Adjusting the shutter speed setting adjusts the width of the slit, and determines degree of film exposure. The table below shows that for a given exposure, opening up the aperture value one stop, for example, decreases shutter speed by one step. The lighting of the final photograph depends on exposure and shutter speed. In more ways then one, different combinations of aperture value and shutter speed allow you to see the same subject in a different light. It's always an eye-opener to see life in a different light.