Shutter, Framing

Les

Well-Known Member
An arrangement of shutters commonly found on an Ellipsoidal Reflector Spotlight.

These four shutter blades (left, right, top and bottom) are positioned in the gate of an ellipsoidal and can be pushed in, pulled out, and moved about at different angles to shape the projected beam of light. The shutters are commonly set in 2-3 planes which allows them to overlap, giving the user the ability to create shapes such as triangles, squares and trapezoids. Framing shutters are usually used to control spill, and the edges can be softened by throwing the instrument slightly out of focus. Framing shutters are normally constructed of stainless steel and are replaceable. Instruments such as the Altman 360Q can frequently warp and burn through framing shutters (especially if out of Bench Focus), but more efficient instruments such as the ETC Source Four rarely, if ever have this problem.

Followspots also have a form of framing shutter frequently referred to as a "chopper". This system consists of an upper and lower set of shutters only. The shutters will open and close in unison by means of mechanical linkage connected to a lever, usually found on top of the instrument. The chopper effect has the resemblance of an eye blinking.
 

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