Difference between revisions of "Leaf shutter"
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| − | A <b>leaf shutter</b> is a [[shutter]] using of a small number of identical overlapping metal blades arranged in a circular pattern to cover a central hole, usually positioned near the iris within | + | A <b>leaf shutter</b> is a [[shutter]] as found in certain cameras, using of a small number of identical overlapping metal blades, called the leaves, to open and close the lens opening. These are arranged in a circular pattern to cover a central hole, usually positioned near the iris within the camera lens. Each blade, suitably pivoted near the housing periphery, is made to move in angular fashion such that the blades together uncover the common central area for a predetermined period of time. This is accomplished by making each blade wave away from the hole and back again on its pivot by a force exerted on it by a common mechanism making a limited amount of fast movement. By doing so, the blades opens and closes the hole, enabling the actual picture to be taken. The movement of the blades is controlled by a clockwork mechanism in the shutter, powered by a strong spring tensioned by setting the shutter before each exposure. The delay between opening and closing the blades determines the exposure time. |
The leaf shutter allows [[flash sync|synchronising flash]] at every available shutter speed, due to the fact that the whole picture area is exposed simultaneously, which is not always the case using the focal plane shutter. | The leaf shutter allows [[flash sync|synchronising flash]] at every available shutter speed, due to the fact that the whole picture area is exposed simultaneously, which is not always the case using the focal plane shutter. | ||
Revision as of 13:43, 9 May 2009
A leaf shutter is a shutter as found in certain cameras, using of a small number of identical overlapping metal blades, called the leaves, to open and close the lens opening. These are arranged in a circular pattern to cover a central hole, usually positioned near the iris within the camera lens. Each blade, suitably pivoted near the housing periphery, is made to move in angular fashion such that the blades together uncover the common central area for a predetermined period of time. This is accomplished by making each blade wave away from the hole and back again on its pivot by a force exerted on it by a common mechanism making a limited amount of fast movement. By doing so, the blades opens and closes the hole, enabling the actual picture to be taken. The movement of the blades is controlled by a clockwork mechanism in the shutter, powered by a strong spring tensioned by setting the shutter before each exposure. The delay between opening and closing the blades determines the exposure time.
The leaf shutter allows synchronising flash at every available shutter speed, due to the fact that the whole picture area is exposed simultaneously, which is not always the case using the focal plane shutter.
The manufacture of leaf shutters is highly specialized, and usually not made by the camera makers them selves. Common types of shutters are the German Compur and Prontor, and the Japanese Copal.
Depending on the way the shutter is arranged with respect to the lens, it is referred to as "between-lens" or "behind the lens" shutter.
Pros
- Leaf shutters can synchronise a flash at any available shutter speed.
- They are generally more compact and less noisy than focal plane shutters.
Cons
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| old shutter of a Contaflex |
- Leaf shutters are typically not capable of shutter speeds as high as modern focal plane shutters; usually the highest speed possible with a leaf shutter is 1/500th of a second.
- Cameras using leaf shutters must either have a shutter in each lens, like the Hasselblad 500, or have the shutter in the camera body, which limits the range of possible focal lengths and the maximum aperture, like the Paxette.
