Confusion in Slow Motion at DVinfo.net

Jim Forrest · March 16th, 2010, 05:20 PM

I just got my 7D yesterday and am still playing with it but the video is beautiful and I have more control over shooting that I have with my video camera. For those of you using the 7D maybe you can help me out here.
I am shooting 30p with a shutter speed of 1/60 which is the normal shooting mode. However I would like to shoot some slow mo and I have been told in order to do that I would need to shoot 30p at a shutter speed of 1/120. When playing back I see no slow mo. Is this something I should do in editing software? Just make the speed 50% and it should look good because shooting at 1/120, and therefore I should have more data and therefore a smoother looking 50% slow mo?

Any direction is appreciated.

David Chapman · March 16th, 2010, 05:34 PM

Hey Jim, the shutter speed isn't controlling the frame rate. If you shoot 30 frames per second, that's what it will be in a 30 frames per second timeline. If you shoot 60 frames per second, you can have slower motion if you interpolate that footage at 30p instead of 60p. That will spread out those frames to be half-speed without frame blending.

I typically shoot 60p and reconform to play at 24p. On a Mac with Final Cut, I have to use Cinema Tools to do this. I know Premiere and After Effects will let you "interpolate" or change the play rate in the app and I think Avid can do the same.

Shutter speed only changes the amount motion blur.

Darrick Vanderwier · March 16th, 2010, 06:47 PM

Hey Jim,
Thanks for the question as I also learned this not that long ago... Just one note (Your sig says canon D7 when I think you meant to say Canon 7D?)
Cheers
:o)

Jim Forrest · March 16th, 2010, 10:33 PM

Yeah you are right...shows how new the camera is.

On slow mo I learning something else as well.

"You need to shoot at 720 60P and then when you import in the bin, right mouse click on the clip and choose property and change the frame rate to 29.97P and it will give you half speed after you place the clip on the timeline."

Ray Bell · March 17th, 2010, 07:32 AM

You can also change the speed with a program like Twixtor... then you can remap the footage to how ever you want it to play....

RE:Vision Effects, Inc. : Products: Twixtor

March 16th, 2010, 05:20 PM	#1
Jim Forrest Major Player Join Date: Jan 2006 Location: Washington DC Posts: 368	Confusion in Slow Motion I just got my 7D yesterday and am still playing with it but the video is beautiful and I have more control over shooting that I have with my video camera. For those of you using the 7D maybe you can help me out here. I am shooting 30p with a shutter speed of 1/60 which is the normal shooting mode. However I would like to shoot some slow mo and I have been told in order to do that I would need to shoot 30p at a shutter speed of 1/120. When playing back I see no slow mo. Is this something I should do in editing software? Just make the speed 50% and it should look good because shooting at 1/120, and therefore I should have more data and therefore a smoother looking 50% slow mo? Any direction is appreciated.

March 16th, 2010, 05:34 PM	#2
David Chapman Major Player Join Date: Mar 2006 Location: Dallas, TX Posts: 346	Hey Jim, the shutter speed isn't controlling the frame rate. If you shoot 30 frames per second, that's what it will be in a 30 frames per second timeline. If you shoot 60 frames per second, you can have slower motion if you interpolate that footage at 30p instead of 60p. That will spread out those frames to be half-speed without frame blending. I typically shoot 60p and reconform to play at 24p. On a Mac with Final Cut, I have to use Cinema Tools to do this. I know Premiere and After Effects will let you "interpolate" or change the play rate in the app and I think Avid can do the same. Shutter speed only changes the amount motion blur. __________________ David Chapman www.davechapfilms.com

March 16th, 2010, 06:47 PM	#3
Darrick Vanderwier Regular Crew Join Date: Dec 2009 Location: St. Catharines Ontario Posts: 69	Hey Jim, Thanks for the question as I also learned this not that long ago... Just one note (Your sig says canon D7 when I think you meant to say Canon 7D?) Cheers :o)

March 16th, 2010, 10:33 PM	#4
Jim Forrest Major Player Join Date: Jan 2006 Location: Washington DC Posts: 368	Yeah you are right...shows how new the camera is. On slow mo I learning something else as well. "You need to shoot at 720 60P and then when you import in the bin, right mouse click on the clip and choose property and change the frame rate to 29.97P and it will give you half speed after you place the clip on the timeline."

March 17th, 2010, 07:32 AM	#5
Ray Bell Regular Crew Join Date: Nov 2004 Posts: 1,414	You can also change the speed with a program like Twixtor... then you can remap the footage to how ever you want it to play.... RE:Vision Effects, Inc. : Products: Twixtor