Thread: Why we need to use ND filters and no increase shutter?

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  1. #1 Why we need to use ND filters and no increase shutter? 
    Tell me please in what cases we need to use ND filters and can't increase shutter?
    Why we can't just make shutter from 1/50 to 1/100, 1/500, we will reduce lighting iin this case too.
    Only when we need open aperture?
    Is it only if we need motion blur effect?
    So we need ND filters only for motion blur effect?

    Thank you in advance
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  2. #2  
    Senior Member Mikael Lubtchansky's Avatar
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    yes keeping the shutter at 1/50 (or rather at 180 degree on a film camera... so half the frame rate 25-> 1/50, 24-> 1/48) keeps the motion blur as it is on a film camera.
    You can go to 1/100 or more for action / sport / sharper still images but it will quickly look jumpy when played back at full speed.

    I you want to keep a filming look try to use ND (and aperture) to control lighting and change shutter only if necessary to produce those motion effect.
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    Senior Member Satsuki Murashige's Avatar
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    ND filters are used to control exposure, and to achieve the desired lens aperture/camera shutter speed combination for aesthetic purposes. If you are only concerned with achieving the correct exposure then of course you can simply increase shutter speed to compensate for opening the aperture, as many still photographers do. This is in effect an 'aperture priority' method of exposure.

    But for cinematography, temporal motion blur and the interval between exposed frames have a larger effect on the viewer because our images unspool over time. Taking this effect into account, shutter speed becomes another photographic tool with which you can affect the viewer, and ND filters are one of commonly used methods of controlling that. The other one is lighting and grip.
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  4. #4  
    Motion rendition and depth of field control. Motion starts to look choppier when the shutter time gets shorter and shorter -- look at the opening battle in "Saving Private Ryan", which was shot with a 45 degree shutter angle (so at 24 fps, the shutter time was 1/192 per frame).
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    Senior Member Owen Rennie's Avatar
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    Plus you look like you know what your doing with a big matte box hanging off the lens haha
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    Senior Member Joel Arvidsson's Avatar
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    I think to many panic about using the shutter instead of an nd (in some cases).
    If you have a locked of shot with a dialog..., or people and camera motion that moves towards or from the camera.
    Where it is more important to watch out for using the shutter (to me atleast) is in panning movements or things moving horisontal in frame.
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  7. #7  
    Senior Member Ketch Rossi's Avatar
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    Quote Originally Posted by Datsenko Alexey View Post
    Tell me please in what cases we need to use ND filters and can't increase shutter?
    Why we can't just make shutter from 1/50 to 1/100, 1/500, we will reduce lighting iin this case too.
    Only when we need open aperture?
    Is it only if we need motion blur effect?
    So we need ND filters only for motion blur effect?

    Thank you in advance
    In the same way ISO is NOT to be replaced instead of using Lights... But instead used to better an image exposure on a given situation, Shutter Speed/Angle should be used to replace the proper use of ND Filters, but instead used as needed to get your Shot, unless there is a specific Artistic reason of course.

    When setting up a shot, you should already know what ISO, Aperture and Shutter Speed/Angle you are going to use in order to give that shot it's intended artistic value, doing it the other way around is just to fix problems, such as NOT enough Lighting etc.

    Again, Shutter can be used at will in order to create an artistic Shot or a given look which perfectly fits the need of your Storytelling... But definitely NOT as a replacement of ND's.
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    Member Damon Chung's Avatar
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    Ketch, what shutter angle do you usually set for fashion?
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  9. #9  
    Senior Member Ketch Rossi's Avatar
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    Quote Originally Posted by Damon Chung View Post
    Ketch, what shutter angle do you usually set for fashion?
    Hey Damon,

    It depends on detail needed to be captured with any given amount of fast movement of subject or textures/clothes in the shot, and if it's just for Frame Extraction or also for Video use.

    But I go from 90˚ for join Frames/Video all the way to 18˚ for just Frames.

    Just know that when going all the way to 18˚ for Frame Extraction and then changing your mind about also wanting to do a video of it, the Cinematic look that you get thru the 180˚ shutter at 24fps will not be there, as you just don't have the blur chasing your frames at 18˚ and the all point to get sharper frames.

    And yeah, of course you'll need a lot more lighting too... :)
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  10. #10  
    Senior Member Nick Morrison's Avatar
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    Quote Originally Posted by Datsenko Alexey View Post
    Tell me please in what cases we need to use ND filters and can't increase shutter?
    Why we can't just make shutter from 1/50 to 1/100, 1/500, we will reduce lighting iin this case too.
    Only when we need open aperture?
    Is it only if we need motion blur effect?
    So we need ND filters only for motion blur effect?

    Thank you in advance
    Motion blur.

    Cinematic motion generally has a 180 degree shutter. So we use ND to help us stay there. Unless you want to get stylized.
    Nick Morrison
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