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-   -   Camera and telecine automatics (http://www.videokarma.org/showthread.php?t=251392)

old_tv_nut 06-18-2011 09:17 PM

Camera and telecine automatics
 
The brochure posted elsewhere here for a Philips camera mentioned optional automatic iris.

This got me thinking about: what was usual operating practice?
I'd think that auto iris mainly is something you would want if shooting in a war zone where you couldn't devote attention to setting it correctly. Not a good thing for studio operations and probably not for outdoor sports either (although there is the late afternoon problem of play moving from sun to shadows). Anyone know how networks and locals tended to use / not use auto iris?

The second area of interest is automatics for telecine chains. The early ones had automatic variable density filter wheels, and I always saw transition effects, at least in the local stations in Chicago, and maybe network stuff too. Automatic iris was used in chains built before the light level could be programmed scene by scene, and it resulted in bad effects on transitions. Typical case: movie cuts from indoor scene to night scene (maybe a train rushing through the night); auto level cranks up over a second or so, but the train is still seen only as a few totally clipped highlights of the headlamp leaving multiple images on a totally black background due to the vidicon lag; then the movie cuts back indoors and the first few frames are way overexposed until the filter wheel can crank back down.

Somewhere along the way, I recall WGN installed some weird sort of automatic color correction on their telecines too. It might have worked acceptably for a single still picture, or if it was used to measure a whole feature and pick one settting, but running it instantaneously (like the auto level control) meant that it responded to image content and would change noticeably from scene to scene or if large areas of the frame changed. I always thought it would have been better to let the film run with whatever faded color it had and let the home viewers adjust for it if they cared to.
Does anyone recall other stations doing this ill-advised automatic "correction" or who produced this equipment?

W.B. 06-19-2011 10:40 AM

Quote:

Originally Posted by old_tv_nut (Post 3006448)
The second area of interest is automatics for telecine chains. The early ones had automatic variable density filter wheels, and I always saw transition effects, at least in the local stations in Chicago, and maybe network stuff too. Automatic iris was used in chains built before the light level could be programmed scene by scene, and it resulted in bad effects on transitions. Typical case: movie cuts from indoor scene to night scene (maybe a train rushing through the night); auto level cranks up over a second or so, but the train is still seen only as a few totally clipped highlights of the headlamp leaving multiple images on a totally black background due to the vidicon lag; then the movie cuts back indoors and the first few frames are way overexposed until the filter wheel can crank back down.

Somewhere along the way, I recall WGN installed some weird sort of automatic color correction on their telecines too. It might have worked acceptably for a single still picture, or if it was used to measure a whole feature and pick one settting, but running it instantaneously (like the auto level control) meant that it responded to image content and would change noticeably from scene to scene or if large areas of the frame changed. I always thought it would have been better to let the film run with whatever faded color it had and let the home viewers adjust for it if they cared to.
Does anyone recall other stations doing this ill-advised automatic "correction" or who produced this equipment?

What you described seemed to be worse on film chains that were made by RCA - and was very noticeable with their TK-27's. It was highly noticeable, in New York, on such stations as WOR-TV and WPIX (though WNEW-TV used the same chain). This "auto iris" fixture seemed in place so as to lessen human involvement in monitoring film picture quality from scene to scene. And Chicago, in terms of telecines, was most definitely an RCA town. (As opposed to New York where several stations had RCA's and a handful - WCBS-TV and WABC-TV come to mind - had General Electric chains.) NBC was the network that used RCA chains in their setup (no surprise - RCA owned them then), but CBS and ABC networks used GE's. Looking at old TV clips online of old network film presentations, did you see such auto-iris examples from CBS or ABC?

old_tv_nut 06-19-2011 11:18 AM

Quote:

Originally Posted by W.B. (Post 3006507)
...Chicago, in terms of telecines, was most definitely an RCA town. ... Looking at old TV clips online of old network film presentations, did you see such auto-iris examples from CBS or ABC?

In terms of the color correction, WGN was definitely unique in Chicago, so I was wondering if it was a third party add-on to their telecine, rather than something from RCA. The auto-level thing was earlier and and was a "feature" most or all stations, I think.

I didn't think of trying to find on-line examples, because on-line clips of old movies are usually from more recent masterings, I think.

W.B. 06-19-2011 11:35 AM

Quote:

Originally Posted by old_tv_nut (Post 3006510)
In terms of the color correction, WGN was definitely unique in Chicago, so I was wondering if it was a third party add-on to their telecine, rather than something from RCA. The auto-level thing was earlier and and was a "feature" most or all stations, I think.

I didn't think of trying to find on-line examples, because on-line clips of old movies are usually from more recent masterings, I think.

I was thinking more the intros of 1970's network airings on shows like The CBS Friday Night Movies or The ABC Sunday Night Movie, which can be seen on sites like YouTube and The Museum of Classic Chicago Television (FuzzyMemories.TV). But WGN did have RCA TK-27's, but may've had their little "add-on" on top of the rest of their setup. Surely they would've had 16mm prints of filmed TV shows and movies, as opposed to their New York sister WPIX which went with 35mm.

old_tv_nut 06-22-2011 09:09 PM

Well, I've looked at a few things on Youtube, and the video coding does so much frame averaging that it's impossible to tell if you are seeing any vidicon lag. - and I haven't found any really early stuff that would likely show the simple automatics.

old_tv_nut 06-22-2011 09:24 PM

Here's one that looks like vidicon lag (but hard to tell with the coding artifacts on top of it) Something bad happens with an overexposure on a transition at 2:30, but it doesn't look like the things I remember, because both scenes are high-key. Also, the fade at 5:18 looks like the telecine exposure is constant.

cbenham 10-13-2011 12:42 AM

Quote:

Originally Posted by W.B. (Post 3006515)
I was thinking more the intros of 1970's network airings on shows like The CBS Friday Night Movies or The ABC Sunday Night Movie, which can be seen on sites like YouTube and The Museum of Classic Chicago Television (FuzzyMemories.TV). But WGN did have RCA TK-27's, but may've had their little "add-on" on top of the rest of their setup. Surely they would've had 16mm prints of filmed TV shows and movies, as opposed to their New York sister WPIX which went with 35mm.

WPIX invented their own auto white-auto black all-electronic unit that worked in addition to the neutral density wheel system by RCA. They showed this device at SMPTE in NYC in 1990, by playing a video tape of a telecined film through it. It did a very nice job of smoothing out the very dark to very bright transitions as well as riding the black levels to prevent detail loss. I remember they even had a name for the device, the PIX-Monitor.
Cliff

old_tv_nut 10-13-2011 08:31 PM

Quote:

Originally Posted by cbenham (Post 3016038)
WPIX invented their own auto white-auto black all-electronic unit that worked in addition to the neutral density wheel system by RCA. They showed this device at SMPTE in NYC in 1990, by playing a video tape of a telecined film through it. It did a very nice job of smoothing out the very dark to very bright transitions as well as riding the black levels to prevent detail loss. I remember they even had a name for the device, the PIX-Monitor.
Cliff

If this also did some auto color balancing, it would describe what I remember seeing on WGN.

W.B. 10-14-2011 01:46 PM

Quote:

Originally Posted by old_tv_nut (Post 3016090)
If this also did some auto color balancing, it would describe what I remember seeing on WGN.

Since WGN and WPIX were/are owned by the same company, I suppose it figures they'd use this same type of apparatus. Does anyone know if Denver's KWGN ever used this?


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