This is a lens hood. If it is) still Sheets (flag out, and in addition a filter stage is present, one speaks of a compendium.
The advantage of a compendium to a pure lens hood, like on the picture, is that you can prevent synonymous for very deep, steep or lying still for Lens highlights irradiation on the lens. At extremely low-flare and very long focal lengths is synonymous is happy to templates, which only minimally more picture to share, as the camera captures. The advantage of the filter stage is explained so of itself ..
Antwort von Axel:
The thing is a front sun visor, function is explained by the designation. Or what you meant? If you mean a Mattebox, which is also a sun visor, but the possibility hineinzuschieben with frames, mostly for filter. The term "mat" comes from the stone age of film making. This refers to a region of the unexposed film stock, achieved through a mask that covers a portion of the Optics. ) The design of a Mattebox often quite large (in Comparison to simple sun visor has been prevented, that the film was exposed body s.dieser unexposed (black =). You could rewind it and so - in camera - to expose once again, with inverted mat would (we say today), so the mask on the opposite page. In this way, go for completely silent periods appears magic double shots and the like.
The historical background is useful for the often confusing terms Mask and Mat understand. A mat are just certain areas of the image that are selected, for example by keying. A mask is a form with which one defines a mat.
Antwort von joey23:
Hood is the marketing term, but technically incorrect. Strictly speaking, this is a lens hood;)