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Live Aid 1985 - BBC Camera Quality

What caused the lines on certain cameras

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AA
aaron_scotland
Im 99% sure I saw this answered on this forum, but I've tried to search live aid and just couldn't find the exact post.

On the Wembley concert of Live Aid 1985, which the BBC filmed, there are lines really quite visible rolling up and down the screen on certain cameras - it seems to just be the two that dolly up and down the front of the stage?

Tried to capture a still of the issue but its tricky, if you watch this clip you'll see it.

My guess is perhaps vibrations being so close to the speakers? Just odd its only those two positions that are effected.

*

FU
fusionlad Founding member
I'm sure it was a few cameras, not just the two you mention.
DA
davidhorman
From the Doctor Who Restoration Team FAQ:

Quote:
4.1 Why do you see parallel lines on the picture if guns are fired?

It's called Microphony. The percussion of the gunfire causes the camera tube to vibrate. Hence the lines. Steps were being considered to remove them from new releases such as the DVD of Caves of Androzani, but was found to be too complex a problem.
NJ
Neil Jones Founding member
This came up here:
https://tvforum.uk/mediatech/tube-camera-picture-effects-43455

Not unique to Live Aid but you can see it on older episodes of Dr Who (as above) and quite a number of tube productions where it occurs on tube cameras. Live Aid is covered in it, however one exception resurfaced 18 months ago:


(this wasn't aired as such, but its been cobbled together from B-Roll film rushes, and part of this performance was not shown due to a power failure (you can see at about 40 seconds in the stadium screen fails when the power went off). The sound quality probably isn't as great as it would have been aired though)
AA
aaron_scotland
From the Doctor Who Restoration Team FAQ:

Quote:
4.1 Why do you see parallel lines on the picture if guns are fired?

It's called Microphony. The percussion of the gunfire causes the camera tube to vibrate. Hence the lines. Steps were being considered to remove them from new releases such as the DVD of Caves of Androzani, but was found to be too complex a problem.


Good find, So yeh looks like it was just sound vibrating the tubes. Thanks!
CO
commseng
Many of the older shows with live music performances had the microphony visable on the pictures.
Loud crowds at sporting events also caused the same issue.
At the time it was accepted, as what else can you do?
Now tube cameras are history, and the effect on these recordings to younger eyes is odd.
NJ
Neil Jones Founding member
Question: Would the effect mentioned have been seen on the live pictures?
CO
commseng
Yes it would have, as it affected the tube, it would have been seen on the pictures from the camera at all points in the chain.
MM
MMcG198
Many of the older shows with live music performances had the microphony visable on the pictures.
Loud crowds at sporting events also caused the same issue.
At the time it was accepted, as what else can you do?
Now tube cameras are history, and the effect on these recordings to younger eyes is odd.


I may be misremembering but I seem to recall some LWT studio-based shows in the 70s and 80s suffered from this when the audience roared with laughter. 'Game for a Laugh' and some of those Dame Edna shows come to mind. Think it was generally the cameras that were embedded within the audience seating area.
EL
elmarko
Man, I’ve always wondered about this. I always thought it was the internal speakers vibrating the tube/mask at the viewer end. Is that possible?
MA
Markymark
Man, I’ve always wondered about this. I always thought it was the internal speakers vibrating the tube/mask at the viewer end. Is that possible?


Well, surely that theory was easily discounted by simply tuning the volume down to zero!?

Anyway, that wasn't an issue, but that said if you tapped the face of some Sony Trinitron tubes, you could make the internal grill vibrate. That's why those CRTs had two horizontal strengthing bars a third and two thirds of the height from the top. Very thin, but once you spotted them, you couldn't 'unsee' them!
HA
harshy Founding member
Aah right I never realised that was an issue but yeah it seems quite obvious now, yeah I imagine the issue is long gone in the digital age.

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