Mastering Shutter Speeds: Page 4
Shutter Speeds and Motion
This sequence shows how the shutter speed that you choose affects the way that moving subjects are recorded by the camera. Remember though that the precise effect will depend on various factors, including the speed of the subject.
For everyday subjects faster shutter speeds will have little effect on the overall result. However, a shutter speed of 1/500sec and above will freeze fast moving objects. Most people do not need the fastest speeds other than to allow wide apertures, although higher speeds are vital to some forms of specialised photography such as balistics testing.
One of the most common shutter techniques is that of panning. If you are shooting a racing car, for example, and press the shutter, using a fast shutter speed of 1/1000sec at the moment the car passes the camera, you will get a frozen, motionless-looking car in front of pin sharp background. Alternatively with a slower shutter speed of 1/60sec, you will get a blurred car as it travels too fast to record on the sensor.
Panning involves following the car with the camera and pressing the shutter release button at the same time, so the car will be sharp but the movement of the camera will blur the background. This takes some practice, especially with fast-moving subjects such as motor racing cars, but adds drama to the image to create a sense of movement and speed.
Flash and Shutter Speeds
Camera specifications will often quote an X- sync speed. This is the fastest shutter speed possible with which a flashgun will work. The sync speed is typically set at around 1/60 to 1/250sec, although higher speeds can be used be used with dedicated hi-speed flash units.
The X-sync shutter speed is determined as the point when the shutter is fully open and the camera sends a charge to the flash to fire. The burst from a flashgun is typically much shorter than the time the shutter is open, but there is an optimal point when the shutter is fully open. If the shutter speed is too fast for the flash, the image will not be fully exposed to the flash burst and areas of the image will receive no light, so black lines appear in the final image. Slower shutter speeds can be used to exploit the ambient or background light.