Safe Recording Speed? at DVinfo.net

Martin Campbell · May 4th, 2010, 11:04 AM

Hi all,

did my first bit of filming the other day (interviews). I really wanted the maximum depth of field to show, so I had the aperture up to max (2.8). Seeing as the interviews were outside and with my speed set to 50, I had to bring down the brightness - so I kicked up the speed, and I don't know what I used but was probably about 300 or something. Anyway, looked fine on screen but the image was a bit stuttery when viewed in post. I always have my speed set at 50 with my regular video cam, and I realise that I should have probably done this here - but I just wondered what is the safest speeds to use up to without having too much of a stutter to the look (and helping to keep the Aperture to it's highest setting for DOF?)

Or should I never stray for that 1/50 speed setting again?!!!

Thanks

Bill Pryor · May 4th, 2010, 12:12 PM

The shutter speed must be set to 1/50 for 24 fps video. Anything else can cause problems, either blurring or strobing. Which is why you use ND filters in motion picture cameras. Shooting video with a DSLR is more like shooting with a motion picture camera than a video camera in that regard. If you want to shoot with your lens wide open for a shallow depth of field, outdoors, you'd need probably an ND.9 and a .6 or .3. Instead of one really dark one, I use the .9, .6 and .3, and any combination of those will usually give me what I need. In bright sun the .9 gets things down to around a 5.6 usually.

If you buy ND filters at a still camera store, they usually don't use the .3, .6 and .9, etc., designations. They call them a No. 2, 4, 8, etc. Same thing, just a different designation system. Some people use the variable ND filters. I don't know much about them as I've always used the standard ones.

Martin Campbell · May 4th, 2010, 05:38 PM

Thanks for that. I shoot in pal 30fps. So can I really use any other speed than 50?

Liam Hall · May 5th, 2010, 01:17 AM

Martin,

PAL is 25fps.

A general rule is to keep the shutter at twice the frame rate, so for 25fps you'd shoot at 1/50th. This is only a general rule. You wont get shot if you change shutter speed. Indeed, there are many times when it is advantageous both from a creative stand point and a technical one.

My advice: test it and see what happens.

Scott Lovejoy · May 5th, 2010, 10:08 AM

Hi Martin,

Like others have said, I'd say for interviews 1/50th is a good place to be. ND's are much better for controlling DoF than shutter speed when you're shooting video, because ND's change nothing about the image except for the amount of light hitting the plane. Changing shutter speed is certainly a creative decision that you can delve into, but I feel like for interviews you want to give your viewer something they're accustomed to (somewhere in the realm of 1/48 - 1/60).

May 4th, 2010, 11:04 AM	#1
Martin Campbell Regular Crew Join Date: Mar 2010 Location: London Posts: 104	Safe Recording Speed? Hi all, did my first bit of filming the other day (interviews). I really wanted the maximum depth of field to show, so I had the aperture up to max (2.8). Seeing as the interviews were outside and with my speed set to 50, I had to bring down the brightness - so I kicked up the speed, and I don't know what I used but was probably about 300 or something. Anyway, looked fine on screen but the image was a bit stuttery when viewed in post. I always have my speed set at 50 with my regular video cam, and I realise that I should have probably done this here - but I just wondered what is the safest speeds to use up to without having too much of a stutter to the look (and helping to keep the Aperture to it's highest setting for DOF?) Or should I never stray for that 1/50 speed setting again?!!! Thanks

May 5th, 2010, 01:17 AM	#4
Liam Hall Major Player Join Date: Sep 2006 Location: London, England Posts: 969	Martin, PAL is 25fps. A general rule is to keep the shutter at twice the frame rate, so for 25fps you'd shoot at 1/50th. This is only a general rule. You wont get shot if you change shutter speed. Indeed, there are many times when it is advantageous both from a creative stand point and a technical one. My advice: test it and see what happens. __________________ Writer-Director-DOP www.liamhall.net

May 4th, 2010, 12:12 PM	#2
Bill Pryor Contributor Join Date: Jan 2003 Location: Kansas City, MO Posts: 4,449	The shutter speed must be set to 1/50 for 24 fps video. Anything else can cause problems, either blurring or strobing. Which is why you use ND filters in motion picture cameras. Shooting video with a DSLR is more like shooting with a motion picture camera than a video camera in that regard. If you want to shoot with your lens wide open for a shallow depth of field, outdoors, you'd need probably an ND.9 and a .6 or .3. Instead of one really dark one, I use the .9, .6 and .3, and any combination of those will usually give me what I need. In bright sun the .9 gets things down to around a 5.6 usually. If you buy ND filters at a still camera store, they usually don't use the .3, .6 and .9, etc., designations. They call them a No. 2, 4, 8, etc. Same thing, just a different designation system. Some people use the variable ND filters. I don't know much about them as I've always used the standard ones.

May 4th, 2010, 05:38 PM	#3
Martin Campbell Regular Crew Join Date: Mar 2010 Location: London Posts: 104	Thanks for that. I shoot in pal 30fps. So can I really use any other speed than 50?

May 5th, 2010, 10:08 AM	#5
Scott Lovejoy Regular Crew Join Date: Jul 2005 Location: Boston, MA Posts: 73	Hi Martin, Like others have said, I'd say for interviews 1/50th is a good place to be. ND's are much better for controlling DoF than shutter speed when you're shooting video, because ND's change nothing about the image except for the amount of light hitting the plane. Changing shutter speed is certainly a creative decision that you can delve into, but I feel like for interviews you want to give your viewer something they're accustomed to (somewhere in the realm of 1/48 - 1/60).