Shutter Speed ~ What is “shutter speed’ all about?
- The shutter helps a photographer to create a sharp image by precisely controlling the amount of time light is permitted to affect the image being formed on the film. (If the light were permitted to continue to hit the film, slightly overlapping images would be formed as the motion continued. These overlapping images would be perceived as ‘blurriness’ because no one image would dominate enough to create the illusion of a sharp image. By capturing a ‘split-second’ of time, the motion/action is cut off before it has the chance to form a blurry image.)
- Shutter speed settings have been standardized so that each setting lets light reach the film for twice as long as the next higher number. For example 1/50th second lets light reach the films for twice as long as a setting of 1/100th second. 1/30th second lets light reach the film for twice as long as 1/60th second, etc.
- The settings are usually shown as whole numbers, but each whole number really represents the fraction 1 over that number. For example, the number 60 would represent 1/60th second; the number 1 would represent 1/1 = 1 second, etcStandard shutter speed settings range from 1 second to 1/1000th second (or faster) plus “B”.
- NOTE: Some newer cameras have shutter speed settings longer than one second. These shutter speeds are usually represented by a number followed by some kind of symbol. For instance, 4 would represent 1/4th second, but 4~ would represent 4 seconds. Using such a system, 30 would represent 1/30th second, but 30~ would represent 30 seconds. Read your camera’s instruction book carefully to make sure that you understand the shutter speed settings for your particular camera.
- “B” (bulb) setting: For very long shutter speeds, a cable release may be required. A cable release is a device that locks the shutter open until you unlock it. When your shutter speed mode is set to the B setting and you use a cable release, you could, for example, lock the shutter open for 2 minutes. The shutter would only close again when you physically unlock the cable release.
Suggested starting points (for best results, bracket your exposure settings)
For subjects that are NOT moving…
- As a general rule of thumb, when hand-holding a camera (that is, when the camera is not mounted on a tripod or other support) the slowest shutter speed you should use is the closest shutter speed setting to 1/ the focal length of the lens you are using. For a standard lens (50mm) the two closest shutter speed settings are 1/60th second and 1/30th second; therefore, the slowest shutter speed setting you should use is 1/30th second.
If there is enough light present in the scene, the following shutter speed settings are suggested for use with ISO 400 speed film … (Note: These are only rough guidelines. Films slower than ISO 400would require the use of slower shutter speeds; with faster films you may use faster shutter speeds.)
- Use 1/125th second for slow moving (walking speed) subjects
- Use 1/250th second for subjects moving at a medium speed (jogging speed)
- Use 1/500th second for fast moving subjects (cycling speed)
- Use 1/1000th second for very fast moving subjects (engine powered, eg. cars or boats)
OTHER KEY INFORMATION
- There is a reciprocal relationship between shutter speed settings and aperture settings.
- Since each shutter speed setting lets light reach the film for twice as much TIME as the next higher number and each aperture setting lets in twice as much LIGHT INTENSITY as the next higher number aperture setting; if you found that your camera’s exposure meter automatic setting for a particular scene was 1/15th second with an aperture of f/8, but you know that to hand-hold a camera you need a speed of at least 1/30th second, you could change the aperture to f/5.6 to let in twice as much light. This would allow you to use a shutter speed of 1/30th second and still have correct exposure.
- If your camera is set to SHUTTER SPEED PRIORITY MODE, whenever you change the shutter speed, the camera will automatically adjust the aperture to compensate.