TV Camera Vibe Criteria

[271828]

Say you have a tv camera mounted on a floor, pointed at a sporting event below. What floor vibe criteria must be satisfied to prevent wiggly or blurry images? Ref to a source would be greatly appreciated.

 

[ChipB]

In photography, you want your shutter speed to be less than 1/60 of a second. Anything greater than that, say 1/30 of a second, the slight shaking of your hand is picked up and the picture may be blurred. As far as sources, it should be in almost any photography book.

I'd say coordinate that with the frequency of your vibration.

 

[cvg]

video cameras don't have a shutter speed, and either way for a sporting event it would be much faster than 1/60 second. Criteria will depend at least in part on how close to the action you are. A small vibration on a telephoto lens may be unacceptable while a much larger vibration on a close up shot would be less noticeable.

 

[271828]

Thanks guys.

Floor vibe due to human activity is almost always in the 3 Hz to 10 Hz range, so 60 Hz and 30 Hz don't help.

It is bound to be affected by distance from the action. For the current problem, I'm talking about cameras mounted near the top level of a big college football stadium.

I know of criteria for microscopes based on ability to perceive the motion, but I haven't been able to find anything for cameras. I looked for telescopes also, but haven't found anything.

 

[ChipB]

cvg:
271828 is mounting this camera in e's room so he can watch her while he is at work! Sporting event would be "sipee cup throwing" or "Let's drop this on the floor and see how long before mommy (or daddy) picks it up". ;-) Yes, I've been there.

All joking aside, no, they don't have shutters but they work similarly. So whatever things may be close by, you don't want them to vibrate your camera faster than your "effective" shutter speed.

http://www.mediacollege.com/video/camera/shutter/

 

[271828]

LOL ChipB. It'll be a while before she can torment us with those tactics.

The shutter speed is interesting, filed away for future use, but I don't think that applied here because those frequencies are so much higher than vibe caused by crowd participation or walking.

For microscopes, they break out vibe into low frequency floor vibe causing "jiggle" and high frequency causing "blur."

Floor vibe is definitely in the "jiggle" category, being usually far less than 10 Hz.

I think the criterion should be a micro-in./sec. vibrational velocity limit similar to microscopes.

I'm inclined to think at this point that nobody's done a study on the subject.

Does anybody know off-hand who makes the fancy cameras used at big time events? I think I'll call them.

Thanks again guys.

 

[cvg]

if you think about it, most of those cameras are either sitting on the floor (rolling) or mounted to the structure with either temp or permanent mount. I doubt that the design of stadium floors is typically based on limiting the amount of jiggle imparted to a camera. Instead, they are based on building codes and standards. Any special design to limit camera movement would have to be over and above the code requirement for servicibility. That said, if it meets the code, the camera probably won't jiggle much except during major events.

 

[ChipB]

My friend who was my best man at my (last) wedding used to be Dan Rather's camera man. I put a call into him over the weekend so when he calls me back, I'll try to remember to ask.

"It'll be a while before she can torment us with those tactics."

Not that long. You've heard it before, and I'll tell you too, enjoy it now. Don't wait for tomorrow. Make it today.

And also:
Spend time with your wife before someone else does.

 

[271828]

Granted, it's not usually the first thing on an EOR's mind but it is possible to need to consider vibrations along with all the typical code stuff.

One of my current projects is to do exactly this and is the source of my original question. The enclosed areas cantilever out about 25 ft. That part of the stadium has a low natural frequency and will be somewhat easy to excite by crowd participation. I've seen footage through cameras that were shaking, so it's very possible. I just don't know how much is too much.