Quote:
Originally Posted by Telecolor 3007
If you mentioned H.D. tube cameras, I'm curios how the image provided by one is.
In Europe we had "Bosch" KCH 1000. Plumbicon and saticon. Never seen images taken with one...[/B]
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BTS was the joint venture of Bosch and Philips.
https://en.wikipedia.org/wiki/Broadc...on_Systems_Inc.
The color performance of HD and SD Saticon cameras is not theoretically different. It depends on the design of the color splitting prisms, which could be the same, the response of the Saticon photoconductor, which was the same, and the color matrix, which could be the same. The resolution of the Saticons was an issue, however, and special HD Saticons with smaller beam size and smaller cathodes were made for HD. This made the predicted life of the HD tubes shorter, and they were only guaranteed for several hundred hours. We did a preemptive tube replacement on our camera at about 800 hours, but there was really no sign of degradation at that time. Compared to later solid-state chip cameras, the tube cameras were noisier, as the faceplate is capacitive, producing a 6dB per octave roll-off. This is compensated by feedback increasing gain by 6 dB per octave, also producing a triangular noise spectrum, so the wider bandwidth of HD increased the noise greatly. Fortunately, the eye is less sensitive to high frequency noise, so the effect was not as bad as indicated by the total noise power.
Nevertheless, the video preamplifiers were limited in frequency response to about 22 Mhz instead of the 32 MHz required to get full horizontal resolution.
Chip cameras, on the other hand, generally have a flat noise spectrum (and less noise over-all), produced by the charge-counting noise of the pixels plus the semiconductor dark noise.
The small spot size also meant limited beam current, so the HD cameras were more subject to highlight overload and "comet-tailing" than SD cameras. The HD Saticon cameras used bias lighting to reduce lag, just as the SD cameras did, and showed the same effects of lag being different for highlights, midtones, and shadows (worst in shadows).