I don't get it

JulesP

JulesP

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Julian
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When shooting video at 30fps or whatever you choose, how can you also set the shutter speed?
Surely the shutter speed will always be 1/30 as in 30fps?
Am I missing something here? My thinking is if you set the shutter speed to 1/50 you should get 50fps:thinking:
I'm not in to shooting proper video with my D7000 but this question has been nagging at the back of my mind:shrug:
 
There is no shutter involved, the mirror is locked up so the image is taken through the lens directly onto the sensor.
 
This is an area that often confuses people. Frame rate, although related to shutter speed is actually independent.

Frame Rate = the number of shots captured in one second (e.g. 24, 25, 30fps)

Shutter Speed = the length of time each frame is exposed for (e.g. 1/48th of a second)

There is something in video called the 180 degree shutter rule and it is very worthwhile learning it. In a nutshell, you should aim for a shutter speed of as close to double the frame rate as possible. So for example, a frame rate of 24fps, you should set your shutter speed to 1/48 (one 48th of a second), for 25fps = 1/50, 30fps = 1/60 and so on.

Of course this means that you will have to control the aperture in order to fully control exposure. A variable ND filter is ideal for allowing you to maintain a constant shutter speed, whilst controlling light.

Here's a good resource that explains this topic perfectly:

http://vimeo.com/videoschool/lesson/56/frame-rate-vs-shutter-speed-setting-the-record-straight
 
JulesP said:
When shooting video at 30fps or whatever you choose, how can you also set the shutter speed?
Surely the shutter speed will always be 1/30 as in 30fps?
Am I missing something here? My thinking is if you set the shutter speed to 1/50 you should get 50fps:thinking:
I'm not in to shooting proper video with my D7000 but this question has been nagging at the back of my mind:shrug:
Click to expand...

Completely independent.

1) Number of Frames Per Second
2) Amount of Time a Shutter is open per frame.

a 50% (or 180 degree) shutter speed is usually used to prevent too much motion blur.
 
The shutter speed cannot be lower than the frame rate (as the shutter obviously needs to completely open at least once per frame to expose the image correctly), but it can be higher.

In general video, the basic rule is to have your shutter speed as double the frame rate. This is called a 180 degree shutter (that lingo comes from the film world when mechanical shutters were used). So when shooting 25fps, you use 1/50 shutter. This is not an absolute rule but it is how most productions are done and anything you see on TV is probably shot this way.

The rule diminishes as you get to extremely high frame rates, for example if shooting at 2500fps (if you have equipment capable of that) it would be impractical to shoot at 1/5000 shutter, because you would need a very fast lens and an absolutely tremendous amount of light.

Selecting a faster shutter speed reduces motion blur, and makes the video look more choppy. You should always use a shutter speed that is in multiples of your frame rate otherwise you can introduce banding issues when shooting under magnetically ballasted lighting. Shooting at a higher shutter speed is normally done for creative effect, for example the beach landing scene in Saving Private Ryan is shot at 24fps (like 99.9% of theatrical films) but with a shutter speed much higher than 1/48. Also, the 'Crank' films are both shot at very high shutter speed to give them their distinct 'rushing' look.

You can experiment yourself, grab a desk fan or something that rotates or oscillates at high speed and film it at different shutter speeds in good lighting and then watch it back. You will be surprised at how much of a difference it makes. It's just like still photography.
 
Hi, first post here

Does this mean if shooting at 24p we will ALWAYS have a shutter speed of around 48/sec ? would it harm us or have any benefits to shoot at a a higher shutter speed say 125/sec

thanks
Mr.D
 
I sat through a Canon seminar about video with a DSLR, I am a Nikon owner, but the principles are the same.

From what I gathered, when the frames are played back, if the "shutter" is high, there is a bigger difference in the picture content between each frame. When the "shutter" is low, the difference in content is more similar the the next frame, and the pictures appear to merge into each other, this gives a smoother transition from frame to frame. Your can shoot at whatever speed you want, but high shutters speeds give a juddery effect when things are moving, as the back ground / subject jumps location across the frame rather than flows across it.

Does that make sense?
 
Thanks for the replies folks - it kind of makes sense - I'll have a play sometime.
As I said, video is not really my thing but it was just bugging me:-)
 
The 'shutter angle' comes from the mechanical rotary disc shutters used on film motion picture cameras or digital ones that use one instead of/in conjunction with a electronic shutter (a lot of cinematographers prefer them). It basically describes the angle at which the shutter is open and so the film/sensor exposed. The standard angle is usually 180 as its a compromise to get 'normal motion blur': when the angle is wider e.g 220 degrees and so exposed longer there is greater blur, but tighter e.g 90 degrees the exposure is shorter with much less motion blur but concurrently much more light is needed and can look 'juddery', this is quite a popular look in war films such as 'Saving Private Ryan' in scenes with explosions etc.
 
Make sure that if you are shooting anywhere with magnetically ballasted lighting you keep your shutter speed in multiples of 50
 
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