C100 jitter at DVinfo.net

Kathy Smith · November 5th, 2013, 12:06 PM

I am getting this strange jitter when I am panning my camera. here is an example. What gives?
Pay attention to the column when the camera turns.

Jon Fairhurst · November 5th, 2013, 02:33 PM

Looks like normal 24fps to me. That pan is in the "dead zone" for film motion.

In general, one should pan at less than 1/7th of the screen per second at 24 fps. You can also whip-pan as it's so disorienting that the audience doesn't notice the judder. Finally, when tracking a person or object, you can move more quickly as the audience will look at the subject rather than the fast moving background.

In short, this is a technique issue at 24fps. You could use a slower shutter to smooth things out, but then things will get blurry when you pan. Shorten the shutter interval and the judder will get worse.

So, you could track somebody, move more slowly, or do a cut. Or shoot at 60 fps. You could even speed up the turn wildly during post to simulate a whip pan. Or you can just accept that the shot you want has judder. :) Depending on your project, you might come up with some additional creative solutions too. :)

Kathy Smith · November 5th, 2013, 04:17 PM

thanks. But if I am not tracking a person to me the jitter is very noticeable. Would walking slower make any difference?

Jon Fairhurst · November 5th, 2013, 04:48 PM

Yes. In particular, panning very slowly will help.

BTW, the 7 second, edge-to-edge rule is based on ASC (American Society of Cinematographers) guidelines. I did a rough count and your turn was about 3 seconds, edge-to-edge. So if you go a bit slower than 1/2 speed, the results should be good.

Of course, this assumes that your shutter speed is roughly 1/2 of the frame time (for instance 1/50 for 24 fps). Since your video is under artificial lights, you might need to run 1/60 in North America to avoid strobing. That shutter speed would be 25% faster than the ASC expects, so you'd need to go with more like 9 seconds, edge-to-edge in that case.

Hopefully, you'll get to test slower pans. I'm curious to know if you find that to reduce the judder to acceptable levels. Best of luck!

Kathy Smith · November 6th, 2013, 09:02 AM

Quote:

Originally Posted by Jon Fairhurst

Yes. In particular, panning very slowly will help.

BTW, the 7 second, edge-to-edge rule is based on ASC (American Society of Cinematographers) guidelines. I did a rough count and your turn was about 3 seconds, edge-to-edge. So if you go a bit slower than 1/2 speed, the results should be good.

Of course, this assumes that your shutter speed is roughly 1/2 of the frame time (for instance 1/50 for 24 fps). Since your video is under artificial lights, you might need to run 1/60 in North America to avoid strobing. That shutter speed would be 25% faster than the ASC expects, so you'd need to go with more like 9 seconds, edge-to-edge in that case.

Hopefully, you'll get to test slower pans. I'm curious to know if you find that to reduce the judder to acceptable levels. Best of luck!

Thanks Jon. I guess I will need to practice more being slower

Jef Gibbons · November 6th, 2013, 11:46 AM

Hi Kathy, definitely something wrong there! You can see it's smooth for a few frames then leaps forward and backward, that's what you are referring to right? Does the footage do that when you click on the untouched file in your finder? Or is it only after you run it through your NLE?

Jef Gibbons · November 6th, 2013, 11:51 AM

Disregard that last post, it was skipping like crazy when I watched it in the forum, but it looked fine on youtube. I think Jon is right!

Evan Bourcier · November 6th, 2013, 03:59 PM

I'll just throw in that I agree it's just a 24fps issue, but I believe it's also an issue no normal viewer will ever notice.

Drew Curran · November 6th, 2013, 04:28 PM

What shutter speed are you set at. 1/48th?

Kathy Smith · November 6th, 2013, 06:32 PM

Quote:

Originally Posted by Drew Curran

What shutter speed are you set at. 1/48th?

yes, 1/48th

November 5th, 2013, 12:06 PM	#1
Kathy Smith Major Player Join Date: Oct 2010 Location: NY, NY USA Posts: 519	C100 jitter I am getting this strange jitter when I am panning my camera. here is an example. What gives? Pay attention to the column when the camera turns. glidecam - YouTube

November 5th, 2013, 02:33 PM	#2
Jon Fairhurst Inner Circle Join Date: May 2006 Location: Camas, WA, USA Posts: 5,513	Re: C100 jitter Looks like normal 24fps to me. That pan is in the "dead zone" for film motion. In general, one should pan at less than 1/7th of the screen per second at 24 fps. You can also whip-pan as it's so disorienting that the audience doesn't notice the judder. Finally, when tracking a person or object, you can move more quickly as the audience will look at the subject rather than the fast moving background. In short, this is a technique issue at 24fps. You could use a slower shutter to smooth things out, but then things will get blurry when you pan. Shorten the shutter interval and the judder will get worse. So, you could track somebody, move more slowly, or do a cut. Or shoot at 60 fps. You could even speed up the turn wildly during post to simulate a whip pan. Or you can just accept that the shot you want has judder. :) Depending on your project, you might come up with some additional creative solutions too. :) __________________ Jon Fairhurst

November 5th, 2013, 04:17 PM	#3
Kathy Smith Major Player Join Date: Oct 2010 Location: NY, NY USA Posts: 519	Re: C100 jitter thanks. But if I am not tracking a person to me the jitter is very noticeable. Would walking slower make any difference?

November 5th, 2013, 04:48 PM	#4
Jon Fairhurst Inner Circle Join Date: May 2006 Location: Camas, WA, USA Posts: 5,513	Re: C100 jitter Yes. In particular, panning very slowly will help. BTW, the 7 second, edge-to-edge rule is based on ASC (American Society of Cinematographers) guidelines. I did a rough count and your turn was about 3 seconds, edge-to-edge. So if you go a bit slower than 1/2 speed, the results should be good. Of course, this assumes that your shutter speed is roughly 1/2 of the frame time (for instance 1/50 for 24 fps). Since your video is under artificial lights, you might need to run 1/60 in North America to avoid strobing. That shutter speed would be 25% faster than the ASC expects, so you'd need to go with more like 9 seconds, edge-to-edge in that case. Hopefully, you'll get to test slower pans. I'm curious to know if you find that to reduce the judder to acceptable levels. Best of luck! __________________ Jon Fairhurst

November 6th, 2013, 11:46 AM	#6
Jef Gibbons Regular Crew Join Date: Mar 2010 Location: Greater Vancouver, BC Posts: 33	Re: C100 jitter Hi Kathy, definitely something wrong there! You can see it's smooth for a few frames then leaps forward and backward, that's what you are referring to right? Does the footage do that when you click on the untouched file in your finder? Or is it only after you run it through your NLE?

November 6th, 2013, 11:51 AM	#7
Jef Gibbons Regular Crew Join Date: Mar 2010 Location: Greater Vancouver, BC Posts: 33	Re: C100 jitter Disregard that last post, it was skipping like crazy when I watched it in the forum, but it looked fine on youtube. I think Jon is right!

November 6th, 2013, 03:59 PM	#8
Evan Bourcier Major Player Join Date: Jun 2012 Location: Mashpee, MA Posts: 251	Re: C100 jitter I'll just throw in that I agree it's just a 24fps issue, but I believe it's also an issue no normal viewer will ever notice. __________________ DSLR Photographer/Videographer from Massachusetts Portfolio at http://ebourcier.com

November 6th, 2013, 04:28 PM	#9
Drew Curran Major Player Join Date: Jun 2006 Location: N. Ireland Posts: 370	Re: C100 jitter What shutter speed are you set at. 1/48th? __________________ Pixol www.pixol.co www.facebook.com/pixolmedia www.twitter.com/pixolmedia