HL001（71.5＊38.5）Fresnel lens (flaky)

Fresnel lens (flaky):

HL001 (71.5*38.5)

Focal length: 29MM

Distance: 12M

Angle: 120 degrees

Fresnel optical lens light is widely used in film photography lighting. The optical system of this spotlight consists of a Fresnel lens (commonly known as a threaded lens) and a spherical mirror. The center of the luminous body of the light source is located at the spherical center of the spherical mirror. By means of the focusing mechanism, the light source and the mirror can be moved back and forth along the optical axis of the Fresnel lens, so that a light beam with a continuously changing angle can be obtained. The non-threaded surface of the Fresnel lens is usually pressed with a variety of patterns, such as "moiré" or "honeycomb," so that the light is properly scattered, so that the lighting effect is soft and uniform, and there is no clear boundary in the irradiated light field. For easy access to light. The beam angle of this lamp can be adjusted within the range of 15° to 60°. The outside of the light box is equipped with a light shield called a concealer. In front of the lens, there is also a frame that can hold light paper. The majority of Fresnel lens spotlights used in cinematic photography lighting use tungsten halogen lamps as the light source, and a series of lamps ranging from 200 watts to 20 kilowatts are formed according to the power of the light source. In addition to halogen lamps, there are Fresnel lens spotlights using carbon arc light sources, commonly referred to as carbon lamps. Carbon lamp has complicated mechanical structure, heavy weight and large volume, and has cyanide gas and smoke pollution. However, due to the high luminous intensity of carbon lamp and wide beam projection surface, it can form high illumination, and it is still difficult to replace by other lamps at present. . In the 1980s, Fresnel lens spotlights using metal halide lamps as light sources have entered a practical stage, and gradually improved.