#16
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Wow. Why did it need such intense lighting? From what I've gathered, early Iconoscopes needed something like 1,000 ft-candles, and that was an insufferable amount. What 2,500 ft-candles was like I can only wonder about.
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One Ruthie At A Time |
#17
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For one thing, the vidicon target voltage (and therefore sensitivity) had to be kept low to minimize dark current variations (shading). Plus, the lag was much worse with a high target voltage. Also, the relay optics were not very efficient, plus absorptive trimming filters were needed to get the color response right.
All the illustrations of usage I have seen are for surgery, microscope slides, or graphic charts, except for the "see yourself on color TV" exhibit at the Museum of Science and Industry in Chicago. The lighting for that consisted of a row of PAR bulbs that cast dark shadows in the subjects eye sockets and still were almost blinding. Even so, the lag was pretty awful. When someone stepped in front of the background mural, you could see the palm frond "through" them for several seconds. I don't think anyone used this camera for live studio work. |
#18
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Sorry, what are PAR bulbs?
Also, to ask a couple more questions, some of the television primers mentioned that WRGB, amongst others, experimented with mercury vapour lamps like the ones in the two pictures I've attached. The large housing is for a water-cooled jacket, and the principal drawbacks were the expense, the weight of the lamp, and that the jacket sometimes leaked. I think there were some issues, too, with the emission spectrum, which caused colours to be rendered into gray scale in unusual ways. Does anyone know how widely this kind of floodlighting was used?
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One Ruthie At A Time |
#19
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Parabolic Aluminized Reflector - like the floodlights used for many decades in outdoor security lamp fixtures
http://www.diynot.com/forums/viewtopic.php?t=139441 Edit - by the way, I do not know how widely mercury lamps were used in TV. |
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