Shutter speed and angle are versatile tools that are often misunderstood by shooters. Learn how they affect motion blur and exposure in your shots, and what settings to use for artistic effects.
An important camera control master when using the exposure triangle is your shutter speed or angle. Once light passes through your lens and your aperture, it arrives at the shutter. Now this may be a physical shutter or a virtual one, but either way it’s job remains the same. It controls how long each frame of video is exposed to light, and perhaps more importantly, it controls how much blur motion will have in your shot. Before we dive any deeper, it’s important to understand the difference between the frame rate you shoot at and your shutter speed or angle. Frame Rates, such as 24, 30, and 60 refer to the number of still images that are recorded each second to create motion video. A 24 frame per second rate means that 24 single frames are recorded each second. Shutter Speed or Angle controls the amount of time that each of those single frames is exposed to light. Adjusting the amount of time each frame is exposed to light will affect how much blur motion will have in your shots, and affect the exposure as well. The term shutter angle comes from the way a traditional film camera works. Each frame of film is exposed to light, and then the camera advances the film to the next frame. In film, this typically this happens 24 times per second. But while the camera moves the film from one frame to the next, the frame must be blocked from exposure to light. A physical shutter allows each frame to be held still while it’s exposed to light, then blocks the light while the film advances to the next frame. The shutter angle refers to the portion of the circular disc that allows light to pass through to expose each individual frame. So a shutter angle of 180 degrees has half a circle exposed to light and half that blocks light. Shutter speed is basically the electronic equivalent to shutter angle. Rather than being measured in degrees, it’s measured by fractions of a second. Let’s see how these two different numbers relate. Let’s look at our 180 degree shutter angle. We have frames are that are advancing every 1/24th of a second, but each single frame is only being exposed for half of that time, or 1/48th of a second. So, if you’re shooting at 24 frames per second, the equivalent shutter speed of a 180 degree shutter angle is 1/48th of a second. When shooting 24 frames per second, a 180 degree or 1/48th of a second shutter will produce natural motion blur that’s similar to what we see with our naked eye. But what about other frame rates? Notice that if you take 360 degrees and multiply it by one half, the result is 180. Also notice that if you multiply the frame rate of 1/24th of a second by one half, the result is 1/48th of a second. This applies to other frame rates as well. If you’re shooting 30 frames per second, a normal shutter speed would be 1/60th of a second, and for 60 frames per second, a normal speed would be 1/120th of a second. A camera with a shutter angle setting would remain at 180 degrees, but the “virtual” shutter would move faster along with the frame rate, keeping the motion blur natural Let’s take a look at an example Here’s a shot of a ceiling fan. We’re shooting at 24 frames per second, with a 1/48th shutter speed. The motion blur of looks similar to what we’d see with our naked eye. Now let’s freeze our shot and take a look at the 24p shot side by side with a 30p shot with a 1/60th shutter, and a 60p shot with a 1/120th shutter. The higher frame rates have a bit less blur due to the faster frame rate, but it still looks fairly natural. If your camera doesn’t have a shutter speed that’s exactly double the frame rate. Simply choose the closest speed available. So, we know how to set a normal shutter speed, and we know that gives us natural motion blur, but what happens when we decrease our angle, or use a faster shutter speed? Taking a look at our mechanical shutter example, let’s change our angle from 180 degrees to 90 degrees. Now, rather than being open for half the time, we’re only exposing each frame for one fourth of the time of each frame. The shutter speed equivalent can be determined by multiplying the frame rate of 1/24th of a second by 1/4th, which results in a 1/96th of a second shutter speed. Because your snapshot of each frame is shorter, Using a smaller angle or a faster speed will cause the motion in your footage to have less blur. Let’s take a look We shot this fountain at various shutter speeds. Notice that as the shutter gets progressively faster, each droplet of water is crisper, and more pronounced. If we freeze our shots, you can really see the difference. Using speeds of 1/250th and above can even freeze motion, which can be useful for pulling stills without blur from your footage. This shot has a 1/250th shutter speed, as we freeze the frame, notice how crisp the car is, even though it’s moving quite fast. shooting 60p with a fast shutter speed can help fast moving objects appear crisp and sharp when you slow it down. this fan was shot at 60 frames per second with a 1/1000th of a second shutter speed, and it’s playing back at 40 percent of normal speed. Notice how the edges of the blade still appear crisp Panning with a fast shutter speed will give you a more strobelike stuccato effect. Here’s a pan of our fountain at 1/250th. notice that it feels more jerky than slower shutter speeds. Now, what happens if use a larger shutter angle or slower shutter speed? Let’s just say we could keep our shutter completely open for the entire length of each frame.. While mechanically this might be impossible, electronic shutters can achieve this. So, a 360 degree shutter exposes each frame for 1/24th of a second, which is the equivalent shutter speed. Here’s our fountain shot with various shutter speeds below normal. Notice that at slower shutter speeds, as our shutter gets progressively slower, each droplet of water has more motion blur. Again, we’ll freeze our shots to really show the difference. You’ll also see a difference when you move your camera, or if your subject in the shot is in motion. Look at this pan of our water shot at 1/6th of a second. If we freeze our shot, it actually looks as if our water droplets are falling in a diagonal pattern In this shot, we used a 1/24th of a second shutter speed and panned along with the car. This keeps our subject relatively sharp, while the background is more blurred than usual, which adds a feeling of fast movement. And finally, in this shot we took it to the extreme by using a 1/6th of a second shutter speed to get a dramatic motion blur from our lights. So, the primary reason to adjust your shutter speed is to achieve the type of motion blur you want in your project. Fast action scenes will often use faster shutter speeds to give a stucatto feeling to the footage, while scenes shot with slower shutters can enhance a dreamlike surreal feel. The second thing your shutter angle or speed will affect is your exposure. Faster shutter speeds will leave your shutter open for a shorter amount of time, allowing less light to hit each frame which creates a darker exposure. Slower shutter speeds will leave your shutter open longer, allowing more light to hit each frame which create a brighter exposure Using a shutter speed that’s twice as long can be offset by closing your aperture by 1 full stop. While using a shutter speed that’s twice as fast can be offset by opening your aperture 1 full stop. If you’ve got a scene that doesn’t have a lot of motion, pushing your shutter speed one or two steps slower than normal can have minimal effect on your motion blur, while giving you a bit more exposure for dark scenes. And unlike gain, there’s no noise added to your image when you use this method. This shot of our lights required using gain to get the exposure we wanted with our shutter speed set to normal, but by changing our shutter to 1/24th, we’re able to switch off the gain, resulting in a cleaner image. Of course, pushing your shutter speed one or two steps faster than normal can reduce your exposure without adjusting your f-stop. Finally, if you ever have flicker in your video from lights or a tv monitor, you can try adjusting your shutter speed to reduce or eliminate it. In this shot, our 1/48th shutter speed causing noticeable flicker with our 60hertz tv refresh rate. Changing our shutter to 1/60th will eliminate the issue. So you know what changing your shutter does, but how do you typically change it? higher end camcorders will typically have a dedicated switch, and may have three different mode of operation. Auto, off, and manual. Leaving your shutter on auto isn’t advisable as your camera will use shutter to control exposure. This can result in shifting amount of motion blur in your shots. The off setting will use a “normal” shutter speed which as we know is 1 over double your frame rate or 180 degrees.. . Manual will allow you to dial in your speed, allowing you to get more or less motion blur in your shots Less expensive cameras will often require delving into the menu system to make changes to the shutter speed. DSLR cameras can often control the shutter by assigning it to a thumb or finger wheel. A firm understanding of how your shutter works helps us to use the exposure triangle effectively. Remember that the primary reason to change your shutter speed is to control the motion blur in your shot, and that the changes in exposure are really a side effect to it’s real purpose.