Please explain: shutter speed in video

Discussion in 'Filmmaking' started by sprinke, May 20, 2011.

  1. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi
    Okay, so I know my way around aperture, shutter speed, and film speed (ISO) well enough for stills photography.

    What I can't seem to wrap my brain around is what effect changing the shutter speed has while recording video. Aperture and ISO make sense, but how does shutter speed come into play? And how does it relate to the fps setting of the selected video mode (e.g., 24fps, 30fps, 60fps)?

    If someone could explain in simple language, that would be great. Thanks!
     
    • Like Like x 1
  2. John M Flores

    John M Flores Mu-43 All-Pro

    Jan 7, 2011
    Somerville, NJ
    shutter speed with video is similar to still photography in the sense that it affects the appearance of motion within a single frame. Imagine a dripping faucet. A still shot at 1/15 would likely show motion blur, while a still shot at 1/1000 is likely to freeze the drop in mid air.

    A frame taken from a video would exhibit the same characteristics - 1/15 shutter speed would show blurring while 1/1000 would freeze the action.

    Where video departs from stills is the cumulative effect of this blurring or freezing of motion. A video shot with a shutter speed of 1/1000 is likely to have an almost stroboscopic or flipbook effect. Here, for example, is a short video comprised of a series of 20FPS stills strung together:

    The Look of Love | Flickr - Photo Sharing!

    A video shot with a shutter speed of 1/15 is likely to err on the other side, with movement being blurred a bit too much. Many shoot for a shutter speed that has just enough motion blur within a frame to help connect the motion to the next frame but not so much as to make it appear stilted, and the general rule of thumb is to use a shutter speed that is 2x the FPS. So if you are shooting at 24FPS, your shutter speed for "filmic" motion should be 1/48 or as close to that as possible (1/50).

    This is only a guideline of course, and creative types play around with these numbers for dramatic effect, i.e., the Omaha Beach scene in Saving Private Ryan is shot with a very fast shutter to give the scene a stroboscopic/hyperreal effect. Look at the rain while you are watching and you will see how distinct each drop and drip is. Amazing cinematography....

    [ame=https://www.youtube.com/watch?v=a6fcaKPIB_E&feature=related]YouTube - ‪Saving Private Ryan Intro HD Part 2‬‏[/ame]
     
    • Like Like x 5
  3. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi
    Thanks John.

    Normally when shooting video I just pop the camera in iA mode and go (mostly because I don't know any better). Do you think the camera (GH2 in my case) is smart enough to select the appropriate shutter speed? How can you find out what shutter speed was used? I don't see it displayed when I'm reviewing the movie clip on the LCD.
     
  4. phigmov

    phigmov Mu-43 Hall of Famer

    Apr 4, 2010
    I was wondering this too - thanks for clarifying :thumbup:

    One more question - presumably the shutter doesn't actually open and close at this speed per frame ? In effect this is a sort of hold-over from the days when the speed of film itself passed in front of the lens (thereby simulating the opening/closing of the shutter as the film has a fraction of a second to expose before flying by) ?
     
  5. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi
    • Like Like x 1
  6. kgartner

    kgartner New to Mu-43

    If you want your video to look like "film" (like how a normal film camera would shoot a movie) you want to shoot at 1/50th on the GH2 @ 24fps. With a shutter speed that long, sometimes it's hard to keep the aperture as wide open as you need it, so I generally stack an ND and polarizing filter on top of my lens to knock down the amount of light getting in.
     
  7. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi
    I'm still curious about these two questions:

    1) is the camera smart enough to select the appropriate shutter speed?

    2) how do I know what shutter speed was used for a video clip?
     
  8. John M Flores

    John M Flores Mu-43 All-Pro

    Jan 7, 2011
    Somerville, NJ
    1) I'm not sure how the camera's algorithm works. I would hope that if you choose a 24p mode it will try to shoot as 1/50 unless, but in bright light that may require stopping down the lens, which would also be moving away from the shallow DOF of the filmic look. If two key components of the filmic look are the 180 degree shutter and large apertures, then two of the most important tools to a stills photographer - shutter speed and aperture - have just been severely restricted. Thus the need for either additional light or ND filters to control the amount of light hitting the sensor.

    2) I am not aware of there being any EXIF-like shooting data for video. It would make life much easier if there was!
     
  9. RetroBoy

    RetroBoy Mu-43 Regular

    I found it handy to be able to control the shutter speed recently while trying to video my golf swing.

    First attempt in program mode in the shade resulted in a lot of movement in each frame.

    Next time I went out in the sun and set it to shutter priority, 1/2000th speed and was able to step through frame by frame and see my hands and clubhead clearly.

    Then I saved it as slowest motion playback speed in Windows Movie Maker and now I have my own swing sequence to review.
     
  10. John M Flores

    John M Flores Mu-43 All-Pro

    Jan 7, 2011
    Somerville, NJ
    That's a great example of why the 180 degree shutter is simply a suggestion and not a rule.
     
  11. Offriver

    Offriver Mu-43 Regular

    47
    May 17, 2011
    Wow - great question and great answers! I never understood this until now. Thanks.
     
  12. daimos

    daimos Mu-43 Veteran

    288
    Jun 23, 2010
    Ottawa,Ontario,Canada
    richard
    Quicktime and movist show the fps. Go to their control panels.
     
  13. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi
    I want to know shutter speed, not the fps.
     
  14. daimos

    daimos Mu-43 Veteran

    288
    Jun 23, 2010
    Ottawa,Ontario,Canada
    richard
  15. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi
    Thank you, this link was posted earlier in this thread and it was very enlightening.

    However, I still want to know if it's possible to discover, AFTER THE VIDEO WAS SHOT, what shutter speed (NOT FPS) was used. If someone knows of software that displays this information, please share!
     
  16. daimos

    daimos Mu-43 Veteran

    288
    Jun 23, 2010
    Ottawa,Ontario,Canada
    richard
    oops sorry. i was reading opposite way.
    i guess i have the next question. what dslr has a shutter angle other than 180 ?
    is it in their tech specs ?

    Edit... i think i follow the thread now. Duuh.
     
  17. Gerald

    Gerald Mu-43 Regular

    67
    Sep 20, 2011
    Always be careful when mixing different shutterspeeds in one video as they have a big influence on the viewers experience. If you do it, do it intentionally. 1/25 th when shooting at 25 fps causes a video-esque kind of feel. Good for some instances, but really weird when the rest is shot at a quicker shutter speed. People notice it but they don't know what is wrong. Basic guideline is to always double the number of frames you shoot at. So 24fps with 1/48, 25fps with 1/50 and 50fps with 1/100.
     
  18. kevinparis

    kevinparis Cantankerous Scotsman

    Feb 12, 2010
    Gent, Belgium
    intresting discussion, that reflects my current learning curve.

    My E-p1 offers almost no manual control in video mode....In low light it seems to apply change of ISO to keep to the right shutter speed, and in good light and wide apertures ups the shutter speed....which is all understandable

    Been experimenting with my 5D... working on the idea that in video that shutter speed is fixed and that the only variables are ISO and aperture.

    The issue I am trying to get my head round is if I shoot knowing I will want to slow the footage down using Final Cut and its Optical flow rendering...should I shoot at a higher than 1/50 to give the algorithms cleaner images to work with?

    Just got a Konovo Slider today and am on a big learning curve....

    K
     
  19. Luke

    Luke Mu-43 Hall of Famer

    Jul 30, 2010
    Milwaukee, WI
    Luke
    • Like Like x 1
  20. sprinke

    sprinke Mu-43 All-Pro

    Apr 5, 2011
    Pasadena, CA
    Debi