24p/30p do's and dont's, HELP!!

[evanprosofsky]

Hi everyone, first time posting here on dvxuser.
I recently purchased a DVX100b, i've been filming with a vx1000 for a long time so it was a big jump. To the point, I have searched and searched and read and read but was unable to find a clear answer. Could someone please explain to me:

1. Flicker? what exactly does it look like, is it good...bad...why does it happen, how do i produce it/get rid of it etc etc

2. Strobing? what exactly does it look like, is it good...bad...why does it happen, how do i produce it/get rid of it etc etc

3. Shutter speed? I understand you are not supposed to go over double your frame rate. (eg. 24p with a shutter of 1/48th of a second), but when filming fast motion things such as cars or skateboarders, i dont think this shutter is fast enough. What are the pros and cons of using a shutter speed under 1/48th with 24p, and over 1/48th.

4. Filming fast motion in 24p. I realize your movements need to be smooth and subtle as if you were using a film camera. I have been shooting skateboarding( link here- http://storage2.vimeo.com/clips/2007/04/12/vimeo.8483892.0a0b0b.mov?6ac006 ) with a tripod, they have been shots with no movement of the camera whatsoever. Some shots look perfect, others look....almost interlaced??? It would be amazing if someone could explain how i should shoot in order to avoid this look. I have heard keeping the person in the frame for seven seconds? Tips like that would really really help me and I would love to hear what all you smart guys have to say.

THANKYOU sooo much. Please someone get back to me, i cant even explain how much having these questions answered would help me.

evan

 

[sk8orinda]

well, iv had my DVX for a couple months, and i dont see any reason why you wouldnt want to go twice as much as the frame rate with your shutter, espeacially with 30p, which looks great with a high shutter of 1/100 or above i think.

the strobing and flickering should only show up in 24p mode, and you might notice it a little when shooting in 30p, but 60i eliminates this all together, but then your back to looking like VX footage.

the flicker doesnt bother most people, and the strobing is meant to be there, look at any movie in theaters, and with all the pans and tilts (if its shot on 35) will stobe, this is good, its one aspect of 35mm that just makes it look... well great the way it does.

the only con of using a high shutter with 24p would probubly be less flicker and strobing you might want if your shooting a film, but when im shooting skating, a high shutter is always good.

 

[andy_starbuck]

Flicker: The longer your shutter is open, the more a moving object displays motion blur in a single frame. The eye sees this blur and understands it to indicate movement that is faster than the film's ability to display clearly. When you increase the shutter speed, the motion blur is reduced. If a person is moving rapidly, then at a higher shutter speed, they will move some distance in the frame without blur. The result is a series of separate images of the person that are harder for the eye to blend together into motion. The result is that the motion appears to flicker. Slowing down the shutter will produce more natural motion blur that will help the eye blend the images together into smooth motion.

Strobing: Film and 24 fps video are progressive, showing an entire frame every 1/24th of a second. When the camera is panned the images of the objects the eye is focused on are showing up in different locations in subsequent frames. If these separate images are close enough together, the eye interprets it as smooth panning motion. Also, motion blur helps the eye interpret the separate frames as smooth motion. The faster you pan, the further apart the object location will be on subsequent frames. At some speed, the pan movement overcomes the motion blur, and you see separate images that are too far apart for the eye to blend into smooth motion. The result is that the whole image appears to pulse or strobe.

The general advice when panning is to count to seven from the time an object enters the frame on one side to the time it leaves the frame on the other. This is just a general idea of how slow the pan needs to be to limit strobing. A slower shutter (enabling more motion blur) might help. And also if the eye is focused on one object that is fairly stationary in the screen, people don't tend to notice the strobing as much. So if the camera keeps the person on the skateboard almost still in the frame, even though the background around them is moving fast enough to strobe, their eye is on the person who is not strobing or flickering -- so they tend to disregard the background strobing.