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  #16  
Old 03-21-2017, 04:34 PM
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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.t.w., some tube cameras had very vivid colours, which I like. On youtube I've seen only C.C.D. camera (an 1989 "Sony") with vivid colours.
Can you find Betacam (not Betacam S.P.) cassettes today?
And can you plase post some images filmed witn your "Sony" BVP-30. Dind't saw on youtube any filming wiht one such camera.
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  #17  
Old 03-21-2017, 05:54 PM
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Quote:
Originally Posted by Telecolor 3007 View Post
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]
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).
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  #18  
Old 03-21-2017, 08:14 PM
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800 hours... man, that about 3 month of camera use. But if they needed more pixels, why they didn't made the tubes bigger, so they could have the same number of "pixels", but larger ones so the tubes could last longer, much longer.
But S.D. camera tubesc last longer, no?
And what is that "comet-tailing effect"?
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  #19  
Old 03-21-2017, 09:06 PM
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Comet tailing is the long persistence of very bright highlights due to insufficient beam current to discharge the photosensor in one TV field.
Here's an example:
https://www.youtube.com/watch?v=l4qamJ1cDfo
Edit: common places to see this were on brass band instruments and women's jewelry or sequined dresses.

Saticons, Plumbicons, and similar tubes have the problem. Special design changes were made over the years to reduce it: diode electron guns, which produce cathode rays with a lower variance of electron velocity (a lower "temperature"); plus special circuits that sense the highlight and momentarily increase the beam current (but reduce the resolution momentarily also).

And yes, SD camera tubes lasted longer.

I think the reasons for not making larger tubes were several, all having to do with increased cost: entirely new and bigger lenses (TV cameras already needed special lenses with long back focus to pass the image through the long path in the prism block); new larger prism blocks; possibly, difficulty in making larger faceplates/targets with good uniformity (requiring new manufacturing equipment as well). Also, a larger faceplate would have more capacitance, making it harder to get the high frequency response needed.

I will note that due to the smaller image size than 35mm film, the depth of field was increased compared to film. It was hard to sell HD as a movie making technology, because cinematographers felt they had plenty of depth with 35mm by using a smaller lens opening, and wanted the capability to reduce depth of field and blur the background more in many shots.
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Last edited by old_tv_nut; 03-21-2017 at 09:21 PM.
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  #20  
Old 03-21-2017, 09:58 PM
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Thanks to all for contributing to this tube camera thread. Great info coming in. Plumbs and Saticons were the day. I have my fav as you know. Keep up the great info on these great cameras...for all of us that remember them. I found my VA-5 adaptor today. Hooray, if I pull my deck from the camera I have a record only deck that can input analog in the field from some other source. Now I can copy my DVD's to Beta!
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Last edited by Dave A; 03-21-2017 at 10:14 PM.
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  #21  
Old 03-21-2017, 11:20 PM
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Another thing about Plumbicons, Saticons, and such:

As the beam scanned the target, in almost all areas (except those pesky comet-tailing highlights), it had more than enough total current to discharge the target. This means that the charge would be neutralized by just the leading edge of the beam (a variable portion due to the varying charge level). So, the effective beam shape wasn't nice and symmetrical, but actually was a crescent shape. The beam was also partially discharging the next lower scan line, so the crescent was like an arc with the center toward the lower right and the pointy ends more up toward the right and down toward the bottom. This effect was called "beam sharpening," and resulted in the resolution for lines and edges slanted from lower left to upper right being better than for lines slanted the other way. A really fancy camera CCU would have a two-dimensional detail enhancer (using analog delay lines, or later, digital processing) that would allow independent adjustment of the detail sharpness for left-slanting and right-slanting lines.
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  #22  
Old 03-23-2017, 03:43 PM
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CEI color camera brochures and prices from 1979.
Cameras designed for field use plus expansion for studio use.

Anyone familiar with this brand?

http://www.bretl.com/tvarticles/docu...10brochure.pdf

http://www.bretl.com/tvarticles/docu...0infosheet.pdf

http://www.bretl.com/tvarticles/docu...330adsheet.pdf

http://www.bretl.com/tvarticles/docu...aPriceList.pdf
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