July 31, 2014, 10:52:53 PM

Author Topic: What does shutter speed control when shooting video?  (Read 4988 times)

UOduck23

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What does shutter speed control when shooting video?
« on: June 21, 2013, 10:02:45 AM »
I'm just starting to explore the video function of my 5D3 and I was hoping for a little clarification. My understanding is that (as with film) the ISO controls light sensitivity and aperture controls the diameter of the lens opening. However I can't seem to wrap my brain around the shutter speed's function in relation to video. With the camera's mirror being locked up what then does shutter speed change? My first thought was frames per second but I doubt that's right.

Thanks in advance for your help. 


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What does shutter speed control when shooting video?
« on: June 21, 2013, 10:02:45 AM »

sjschall

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Re: What does shutter speed control when shooting video?
« Reply #1 on: June 21, 2013, 10:08:55 AM »
It's exactly the same concept as shooting stills, but just shooting a bunch in a row to make video. Shutter speed controls how fast the shutter opens and closes to expose a frame. A slow shutter speed (i.e. 1/30) will give you slight motion blur which will create "smoother" looking video, while a faster shutter speed (i.e. 1/500 or 1/1000) will give you a more "strobing" look (the example that gets thrown around is the opening scene to Saving Private Ryan, which was shot at a high shutter speed). Just as in stills, high shutter speeds will lower the exposure of the video and slow shutter speeds will raise the exposure. People generally say to keep the shutter speed at twice the frame rate (i.e. 24 frames per second -> 1/50 shutter speed, or 30 frames per second -> 1/60 shutter speed) but you do not have to do this, often times you can "break" the rule to get the look you want! I particularly love using higher shutter speeds when shooting scenes with more action, i.e. sports, dancing, etc.

Frame rate is set through camera settings in the menu, that's just how many individual still frames per second the camera is stringing together to create video. Hope that helps.
« Last Edit: June 21, 2013, 10:12:32 AM by sjschall »

dougkerr

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Re: What does shutter speed control when shooting video?
« Reply #2 on: June 21, 2013, 10:41:02 AM »
In a traditional cinema film camera, what we would call "shutter speed" controls how long the shutter is open for each frame, a different matter from how often the frames occur. It is actually usually expressed in terms of shutter angle in degrees, with 360° meaning a shutter time that is exactly the interframe time.

It is very common to use a 180° shutter angle, which at a frame rate of 24 f/sec is an exposure time of 1/48 sec.

This, combined with the aperture, affects the exposure.

This also effects the degree of visible motion blur, although the impact of this is a bit different in motion picture work than in still photography. Shorter shutter speeds impart a "crisper" view (some would say "more urgent") to the image of a moving object, even though it is "moving" as the eye sees it. Thus the cinematographer may choose a shutter angle partly for aesthetic reasons.

This is a nice discussion of the matter:

Shutter Angle - How to make your DSLR video look like film Small | Large


We often have a similar opportunity in digital cameras in video mode. At 30 f/sec, a shutter time of 1/60 sec corresponds to a "180°" shutter angle in a film cinema camera.

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Doug

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Re: What does shutter speed control when shooting video?
« Reply #3 on: June 21, 2013, 10:52:26 AM »
Look at the video example in this article.... 53 secs, told me everything I needed to know:-)

http://cameradojo.com/2011/08/15/why-shutter-speed-matters-with-dslr-video/

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paul13walnut5

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Re: What does shutter speed control when shooting video?
« Reply #4 on: June 21, 2013, 11:45:53 AM »
Forget shutter angles etc, sledgehammer to crack a nut.

Simple question: What does shutter speed control when shooting video?

Simple answer: Exposure.  Just like in stills.

In video your shutter speed is usually constant, and usually at 1/50th if you live in a PAL region or are shooting 24frames, or 1/60th if you live in an NTSC region.

Because the shutter is usually fixed you become more reliant on your high ISO's or supplementary lighting in lower light, and filtration, usually ND filters in bright light.

You can slow the shutter a little (to 1/30th to let in a bit more light) or you can speed the shutter up, but it starts to have crazy effects on the rendering of motion.  Leave it at 1/50th ot 1/60th and get a fader ND.

bchernicoff

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Re: What does shutter speed control when shooting video?
« Reply #5 on: June 21, 2013, 01:15:13 PM »
Look at the video example in this article.... 53 secs, told me everything I needed to know:-)

http://cameradojo.com/2011/08/15/why-shutter-speed-matters-with-dslr-video/


I was about to suggest the same video. You saved me the trouble of finding it! By extension this explains why ND filters are important with video...with your shutter speed effectively locked, the only way to control depth of field in daylight is with ND filters.
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sjschall

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Re: What does shutter speed control when shooting video?
« Reply #6 on: June 21, 2013, 06:20:59 PM »
I would have to argue that your shutter speed is never locked. It's just a matter of choice. Similar to how aperture changes your depth of field, you would never assume to "lock" the aperture wide open to avoid deep DOF. You just choose what depth of field fits the look you are trying to achieve. In my experience shooting DSLR video, I often raise the shutter speed to go for that look, or to be able to get shallow DOF in bright settings. Sure, if you're starting out by all means use the 180 degree rule as a guide to get a great look, but you don't have to set it to 1/50 and never ever change it.

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Re: What does shutter speed control when shooting video?
« Reply #6 on: June 21, 2013, 06:20:59 PM »

paul13walnut5

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Re: What does shutter speed control when shooting video?
« Reply #7 on: June 21, 2013, 07:14:50 PM »
Over the duration of any given clip it is likely to be consistent.

I would adjust my aperture, filtration, lighting, iso before I would deviate from 1/50th.
I would only shoot at a speed other than 1/50th for a very specific purpose and it would be limited to when absolutely required.

I've only been shooting video professionally for 11 years, and use a video camera of some description maybe 3 days out of five on a bad week.

Locked was perhaps the wrong word.  And of course if you wish to alter your shutter during a take thats technically possible and if you want to do that then it's a free world for the most part.

I can only speak as to what I was taught during my training and what I've experimented with and found to work in my professional life.

If you shoot some footage at 1/500th and some at 1/50th, it isn't going to cut so well together.

Stills shooters often forget that video is contiguous. 

The Op is free to shoot whatever shutter they like, of course they are, of course you are.  Rules are there to be broken right?

Best wishes from Scotland.

zim

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Re: What does shutter speed control when shooting video?
« Reply #8 on: June 23, 2013, 01:07:23 PM »

I would adjust my aperture, filtration, lighting, iso before I would deviate from 1/50th.
I would only shoot at a speed other than 1/50th for a very specific purpose and it would be limited to when absolutely required.


Would an example of that be slow motion?

risc32

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Re: What does shutter speed control when shooting video?
« Reply #9 on: June 23, 2013, 02:56:02 PM »
what does the shutter speed control while shooting video? i have no idea. It's not controlling my camera's shutter. if that is what you are asking, again, i have no idea.

rs

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Re: What does shutter speed control when shooting video?
« Reply #10 on: June 23, 2013, 03:31:25 PM »

I would adjust my aperture, filtration, lighting, iso before I would deviate from 1/50th.
I would only shoot at a speed other than 1/50th for a very specific purpose and it would be limited to when absolutely required.


Would an example of that be slow motion?
Slow motion would typically be shot at a frame rate much faster than 25fps to make it the motion appear smooth when played back - the rule of thumb Paul quoted still holds true - have a shutter speed equal to approx half time the frame represents. So, 24fps and 25fps at 1/50th of a sec, 30fps at 1/60th of a sec, and if you're shooting slow motion at 60fps, 1/120th of a sec. If you have a camera capable of filming at 1000fps, 1/2000th of a sec shutter speed would do the trick.

what does the shutter speed control while shooting video? i have no idea. It's not controlling my camera's shutter. if that is what you are asking, again, i have no idea.
When shooting video (or previewing the scene in live view), the mechanical shutter stays open and an electronic shutter operates instead. That's what's controlled here.
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paul13walnut5

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Re: What does shutter speed control when shooting video?
« Reply #11 on: June 23, 2013, 06:30:32 PM »
The shutter speed is effectively the speed of the read off from the vertical scan of the image device, the furation of how long the scan is. 

The longer the duration if the scan the more details are blurred, which becomes important in terms of the perception of motion. Shutter angle isn't that helpful as an expression because unless you go to something like a sony f65 there isn't a shutter disc to speak of, much the same way as an slrs shutter curtains aren't really used for video.

You might want to use a faster shutter when using a faster transport rate, or if you intend to do frame grabs for print or review, say like practising your tennis swing on camera, 1/50th might be too blurry.   A fast shutter can also be used to make an action shot more dynamic, say in car adverts if you wanted to make more of the cars alloy wheels.

For interview or general dialogue scenes it would look pretty nasty.

zim

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Re: What does shutter speed control when shooting video?
« Reply #12 on: June 24, 2013, 03:51:07 PM »
if you're shooting slow motion at 60fps, 1/120th of a sec.

ah thanks for spelling that out.

Regards

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Re: What does shutter speed control when shooting video?
« Reply #12 on: June 24, 2013, 03:51:07 PM »

cookinghusband

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Re: What does shutter speed control when shooting video?
« Reply #13 on: June 25, 2013, 09:20:42 AM »
what does the shutter speed control while shooting video? i have no idea. It's not controlling my camera's shutter. if that is what you are asking, again, i have no idea.
The duration that the CMOS record(cumulate light energy). This is the same for Live view mode. The circurtry in the CMOS decide how long to record( duration to register light) and pass infor to the processor to work on.

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Re: What does shutter speed control when shooting video?
« Reply #13 on: June 25, 2013, 09:20:42 AM »