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first major element of the camera
lens, glass
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focal length
distance from the optical center (where light crosses) of the lens to the front surface of the imaging element (usually CCD imager), measured in mm. long lens=tight shot=large mm#s. short lens=wide shot=small mm#s.
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lenses are often referred to by their
zoom ratio, longest focal length (tightest angle) to shortest focal length (widest angle) lens.
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telephoto lens
long focal lengths
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common professional studio and ENG lens ratios
14:1, 15:1, 18:1 and 20:1
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common EFP and telephoto sports ratios
40:1, 70:1, 86:1
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professional lenses are labeled by
zoom ratio and shortest focal length, multiply 2 numbers to figure out the longest focal length, mm
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wide shot lens
low zoom ratio, low shortest focal length
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tight shot lens
high zoom ratio, high shortest focal length
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range extender or teleconverter
increases the focal length of a lens but not zoom ratio. 2x extender is most common, doubles telephoto capability. cuts down amount of light (by 2 f-stops). also only gets a wide shot half as wide as before
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depth of field
subject area shot by the camera that is in focus, area starting a certain distance from the camera and extending even further away from the initial focus point
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1st variable that affects DOF
iris opening/aperture/f-stop setting. tiny opening/aperture=large DOF=high f-stop#. big opening/aperture=small DOF=low f-stop#
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2nd variable that affects DOF
focal length/lens type. influences DOF most. wide shot=large DOF=short lens (more in focus). tight shot=small DOF=long lens (less in focus)
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3rd variable that affects DOF
camera to subject distance. large distance=large DOF, small distance=small DOF
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most used lens in broadcasting and high end video production
canon and fujinon
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dempster cameras
studio A/B-Ikegami HK 388W CCD camers with Canon 20x8 box studio lens with 2x range extenders. ENG/EFP-Panasonic AG-HMC80 SDHC cameras with 12:1 lens or JVC GY-HM700U SDHC cameras with Canon 14:1 lens
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filters
2nd major element of camera, alters the incoming light to create a special effect or to compensate for excessive color or brightness characteristics
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where filters are located
before the lens (add-on assembly called a matte box attaches to the hood of the lens for specialized drop in filters) and after the lens (in camera body in filter wheel)
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1st use for filters
special effects: star, image inverter, fog/diffusion, cross, multi-image, and center sharp features, before the lens, rarely used
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2nd use for filters
color temperature adjustment: reduce high color temperature to lower levels, after the lens in filter wheel
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3rd use for filters
cutting down on large amounts of light, neutral density filters, after the lens in filter wheel, used outside to cut down sunlight or inside to manipulate DOF
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