Frame rate for slow motion? at DVinfo.net

Denny Kyser · September 21st, 2007, 07:26 AM

I am going to be filming some archery hunts this fall, is there a frame rate that you recomend for this over another. I want to be able to do some super slow motion and not sure if 60 fps is the best choice for this or not.

Thanks

Bill Pryor · September 21st, 2007, 09:22 AM

The camera only shoots at 24fps and 30fps. It would be nice if it did do 60fps. The 1/60 shutter speed is standard for 30fps (60i). I've shot at 1/100 (in 60i) for shots I planned to slomo, but I really couldn't see any perceptable difference. You go too high with it and you can get some funky effects. Best thing is to do some tests before doing it for real.

Denny Kyser · September 21st, 2007, 09:56 AM

sorry for the wrong termonology I am very new to this. I am a photographer with a desire to learn video. I usually shoot at 25i and like it alot, but wasnt sure if that would be good for this situation.

I will practice some before and try and figure it out.

Bill Pryor · September 21st, 2007, 10:16 AM

People often get frame rate and shutter speed mixed up. You said 25i...you mean 25p or 50i, I assume. Are you in PAL-land? The quality of slow motion you get is going to depend more on what software you use than anything else. Some systems are better than others, and there's some software called Twixtor that is reputed to be very good.

Tony Tremble · September 21st, 2007, 10:53 AM

There is a formula but I've forgotten it.

If I were shooting a 25F film and wanted some slo-mo sequences in it I would shot those at 50i and with a shutter speed of 5x that of the field rate i.e. 250.

I would then deinterlace and slo-mo the footage using an optical flow solution like twixtor, shake or Motion 3 have. By shooting 50i (60i) you'd have more temporal samples than 25F (24F & 30F).

If I find the formula I'll post it.

Steven Dempsey · September 21st, 2007, 05:12 PM

The formula for NTSC is the following:

Shoot at 60i at 1/120th shutter speed
Bring footage into a 60i timeline and deinterlace and export it which should essentially give you a 60p file.
Import into a 24p project timeline and set the speed to 40%
Make sure frame blending is off

The theory behind the 1/120th shutter speed is that when it is slowed down to 40%, on a 24p timeline, you have the equivalent of 1/48th shutter speed...

Denny Kyser · September 21st, 2007, 06:27 PM

Thanks for the detailed information
I have both Vegas and Adobe Premier CS3 for processing

September 21st, 2007, 07:26 AM	#1
Denny Kyser Major Player Join Date: Aug 2007 Location: Warren, Pa Posts: 785	Frame rate for slow motion? I am going to be filming some archery hunts this fall, is there a frame rate that you recomend for this over another. I want to be able to do some super slow motion and not sure if 60 fps is the best choice for this or not. Thanks

September 21st, 2007, 05:12 PM	#6
Steven Dempsey Disjecta Join Date: Apr 2004 Location: Seattle, Washington Posts: 937	The formula for NTSC is the following: Shoot at 60i at 1/120th shutter speed Bring footage into a 60i timeline and deinterlace and export it which should essentially give you a 60p file. Import into a 24p project timeline and set the speed to 40% Make sure frame blending is off The theory behind the 1/120th shutter speed is that when it is slowed down to 40%, on a 24p timeline, you have the equivalent of 1/48th shutter speed... __________________ Try my Digital Therapy: http://www.pinelakefilms.com/digital_therapy.html Films on ExposureRoom: http://exposureroom.com/members/disjecta.aspx/videos/

September 21st, 2007, 09:22 AM	#2
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	The camera only shoots at 24fps and 30fps. It would be nice if it did do 60fps. The 1/60 shutter speed is standard for 30fps (60i). I've shot at 1/100 (in 60i) for shots I planned to slomo, but I really couldn't see any perceptable difference. You go too high with it and you can get some funky effects. Best thing is to do some tests before doing it for real.

September 21st, 2007, 09:56 AM	#3
Denny Kyser Major Player Join Date: Aug 2007 Location: Warren, Pa Posts: 785	sorry for the wrong termonology I am very new to this. I am a photographer with a desire to learn video. I usually shoot at 25i and like it alot, but wasnt sure if that would be good for this situation. I will practice some before and try and figure it out.

September 21st, 2007, 10:16 AM	#4
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	People often get frame rate and shutter speed mixed up. You said 25i...you mean 25p or 50i, I assume. Are you in PAL-land? The quality of slow motion you get is going to depend more on what software you use than anything else. Some systems are better than others, and there's some software called Twixtor that is reputed to be very good.

September 21st, 2007, 10:53 AM	#5
Tony Tremble Regular Crew Join Date: Oct 2006 Location: United Kingdom Posts: 451	There is a formula but I've forgotten it. If I were shooting a 25F film and wanted some slo-mo sequences in it I would shot those at 50i and with a shutter speed of 5x that of the field rate i.e. 250. I would then deinterlace and slo-mo the footage using an optical flow solution like twixtor, shake or Motion 3 have. By shooting 50i (60i) you'd have more temporal samples than 25F (24F & 30F). If I find the formula I'll post it.

September 21st, 2007, 06:27 PM	#7
Denny Kyser Major Player Join Date: Aug 2007 Location: Warren, Pa Posts: 785	Thanks for the detailed information I have both Vegas and Adobe Premier CS3 for processing