Converting from Shutter Speed to Angles (Camera Lesson 03)

Summary: Ryan shows you how to convert from shutter speed to shutter angle and back again.

Length: 1:07 minutes

Video Lesson
Transcript

Introduction

In this video I’m going to show you how to convert your shutter speed to shutter angles and back again.

Shutter Speed and Shutter Angle

So if you find yourself in the situation where you need to convert from shutter speed to shutter angle, here is the equation that you need to use.

Shutter Angle to Shutter Speed Equation

You take your frame rate, multiply it by 360, and then divide by your shutter speed. So lets say you needed to figure out what the shutter angle is for 1/50 of a second at 24 frames per second (fps). Is would be 24 times 360 divided by 50, or 172.8 degrees.

Now lets say you needed to go the other way: you use the same equation, only this time you divide by the angles. So if you wanted to find out what 180 degrees is in shutter speed at 24 fps, it would be 24 times 360 divided by 180, which equals on forty-eighth of a second.

If you have any comments or questions, leave them in the comment section below, and then come join me in the next video.

10 replies
  1. poe
    poe says:

    Hello Ryan, thank you for making so great video. When the camera can choose shutter speed and angles at the same time, which I should put on light meter to use? I mean, for example, I set 180 degree ,24fps, but 1/400 shutter speed. [some people say fast shutter speed for freeze move is easier to do green/blue key. So I guess I would use 1/400 on light meter to measure. Is it correct? Thank you.

    Reply
    • Ryan E. Walters
      Ryan E. Walters says:

      Poe,

      I’m not sure I understand your question. Can you please clarify what you mean, and hopefully I’ll be able to better help you out. 🙂

      Shutter speed and shutter angle are referring to the same thing- how long the shutter is open on the camera. So at 24 fps, it would be impossible to have a shutter of 180 degrees and a shutter of 1/400. At 24 fps, 180 degrees equals a speed of 1/48. (A shutter of 1/400 at 24 fps equals about 22 degrees.) So you can either have a shutter of 1/48 (180 degrees) or 1/400 (22 degrees), but not both.

      If your question is just whether to put shutter or degree on the camera and on your meter, then I would make your camera and meter match. If your camera only shows speed, make your meter read in speed. If your camera only shows degrees, make your meter read in degrees. If your camera does both, choose the one that makes the most sense to you, and then make your meter match.

      I hope that helps- if not let me know. 🙂

      Reply
  2. Tim
    Tim says:

    Shutter angle dates back to the days when there was a rotating disk that acted as the shutter for film motion cameras. Depending on how much of an angle was cut out of the disk, the shutter was open longer or shorter.

    While most cameras no longer use this measurement now that so many are switching to digital cameras, it is still important to understand what shutter angle is. Plus if you are in the industry long enough, you will most likely need to know the conversion since some high end digital cameras (like the ARRI Alexa and Blackmagic Cinema Camera) still use this measurement. There is also the chance that you’ll work with film motion cameras since they are still used due to their artistic quality.

    Reply
  3. fjvivek
    fjvivek says:

    1. explain minimum and maximum shutter angle use?
    2. is necessary to change shutter angle when frame(24fps) rate increase or decrease?

    Reply
    • Tim
      Tim says:

      Very good questions!

      1) Making the shutter angle smaller is equivalent to having a faster shutter speed. Making the angle larger means a slower shutter speed. These affect the amount of blur in the image, just as shutter speed affects blur. There are also minimum and maximum shutter angles based on physics. The max will probably be 360 or close to it, meaning the sensor is constantly open. Shutter speed example would be 24 fps with a 1/24 sec shutter. Minimum could be a small slit, just enough to let some light through. This would also require very bright lights.

      2) For normal motion blur, an angle around 180 is used. If your recording framerate will be the same as the playback framerate, then you don’t need to adjust the shutter angle. Example: if you are filming a 48 fps shot but will also be playing it back at 48 fps, then 180 degree shutter will create a normal motion blur. However if you are filming at 48 fps and you will play back at 24fps, then you have to decrease the shutter angle to 90 degrees to create a normal motion blur at that reduced play back speed.

      Reply

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