Understanding video frame rate and shutter speed

Capturing visually pleasing video content requires understanding two related but different settings: frame rate and shutter speed. Photographers often confuse the two.

Frame Rate

The frame rate of video content is the number of individual frames shown to the viewer in one second. To the human eye, anything over 10-12 frames per second (fps) will appear as motion.

Film content and most movies are captured using 24 fps (23.976 fps, to be precise).

Television content has historically been broadcast at 30 fps (29.970 fps, to be precise) for NTSC televisions in North America and Japan and 25 fps for PAL televisions in Europe.

Newer ATSC broadcast standards for HDTV allow for frame rates of 24 and 30 fps at 1080p resolution and 60 fps at 720p resolution. The latest version of the ATSC broadcast standard supports 4K resolution up to 120 fps.

Online video sites like YouTube allow for standard frame rates like 24, 25, 30, 48, 50, and 60 fps.

Shutter Speed

When capturing video, shutter speed is the time each frame is exposed. This is typically a fraction of a second for video, like 1/48 sec or 1/60 sec.

Film motion picture cameras use a rotary disc shutter to achieve their exposure times, with shutter speed indicated as a shutter angle. While digital video cameras don’t have a rotary disc shutter, higher-end video cameras allow videographers to set their shutter speed using a fraction of a second or as a shutter angle.

For film captured at 24 fps:

  • 360° – 1/24 second
  • 180° – 1/48 second
  • 144° – 1/60 second
  • 90° – 1/96 second
  • 72° – 1/120 second
  • 45° – 1/198 second

Video captured at 24 fps with a shutter angle of 180° (1/48 second) exposes each frame for half the time the shutter is open.

Video Motion Blur

In still photography, photographers aim to freeze motion and provide razor-sharp images. In scenes containing movement, this is achieved with high shutter speeds, from 1/250 to 1/8000 second.

Videography is different. Using high shutter speeds with video content does freeze motion on each frame, resulting in very crisp individual images. However, when played back at standard video frame rates, the action can appear hyper-realistic and give the viewer a jittery, unsettled feeling.

The most visually pleasing video content has motion blur in each frame, giving the footage a smoother, more cinematic look. See the video above for examples of motion blur at varying shutter speeds.

You can also see this cinematic motion blur by pausing a scene in a movie on your TV. While the subject will be in focus, you’ll notice a considerable amount of motion blur as it moves in the scene.

The following frames show how the motion of a spinning bicycle wheel is blurred at varying shutter speeds.

Motion blur of a spinning bicycle wheel at 1/48 sec shutter speed.
Motion blur of a spinning bicycle wheel at 1/96 sec shutter speed.
Motion blur of a spinning bicycle wheel at 1/200 sec shutter speed.

The 180° Shutter Rule

The film industry has a rule of thumb often used to achieve natural-looking motion blur in video content called the 180° Shutter Rule.

The 180° Shutter Rule states that you set your shutter speed to 1/frame rate x 2. So, at a frame rate of 24 fps, the correct shutter speed is 1/48 second. For 30 fps, a 180° shutter would be 1/60 second.

Since digital cameras do not use a rotary shutter, some shutter speeds may not be available. You can use the closest shutter speed to achieve the cinematic motion blur in your footage.

For example, if your DSLR does not have a 1/48-second shutter speed, 1/50-second would be the closest choice for 24 fps footage. For 30 fps footage, choose a 1/60-second shutter speed.

Cinematic Look

Because audiences are conditioned by viewing decades of movie content, they anticipate video content with a cinematic look, using 24 fps with 1/48 sec shutter speeds to achieve the “typical” motion blur.

Older TV content has often been shot at higher shutter speeds, giving a distinct “video camera feel” to the footage.

Creative Use of Video Shutter Speed

The 180° Shutter Rule is a rule of thumb to achieve normal-looking motion blur in video content.

Faster shutter speeds can be used for dramatic effects. For example, the D-Day sequence in Saving Private Ryan was shot at a 45° shutter (1/198 sec) to highlight the explosions’ jerky motion and extreme detail.

In contrast, slower shutter speeds can create blurry, dream-like sequences.

Faster shutter speeds can also be essential when filming fast-action sports or fast-moving wildlife. The 180° Shutter Rule speeds will introduce too much blur in fast-action sequences. Depending on the speed of motion in a particular scene, a faster shutter speed, like 1/120 second or faster, can help with fast-moving action.

When your scene involves dramatic camera moves like panning or tilting, be aware of shutter speeds and increase them if necessary. For example, a moderately fast camera pan from left to right at 24 fps and 1/48 second may look too jerky or blurred. Increasing the shutter speed can help in this situation.

Neutral Density Filters for Video

In still photography, neutral density filters slow shutter speeds to create creative effects, such as motion blur in water or clouds.

In videography, neutral density filters are far more critical for maintaining the desired aperture and shutter speed in brightly lit scenes.

Cinematographers often want to choose an aperture and depth of field for a particular scene. For a shallow depth-of-field, this means shooting with the lens wide open at f/4 or f/2.8, allowing lots of light to reach the sensor.

For brightly lit scenes, particularly outdoors, after lowering ISO sensitivity to its lowest setting, the only way to achieve proper exposure is to increase the shutter speed. But if the shutter speed is too fast, the resulting video will have an unnatural-looking motion blur or lack thereof.

By adding a neutral density filter to the lens, the camera operator reduces the light reaching the sensor and can lower the shutter speed to achieve the desired motion blur.

Frame Rate Recommendations

Photographers new to video may assume they should shoot at the maximum frame rate their camera supports if they want the highest-quality video. This is not the case.

In most scenarios, the frame rate you deliver will be dictated by the platform that delivers your content. For example, a feature film will be 24 fps, while broadcast TV will likely be 30 fps.

Most video content is delivered to viewers using either 24 or 30 fps. In my shooting, I target 24 fps for projects that I want to have a cinematic, film-like appearance. For run-and-gun videos, mainly when I am hand-holding the camera or with a fair amount of panning or camera motion, I will typically target 30 fps with its slightly higher frame rate and shutter speed.

What about 60 fps, the other commonly supported frame rate? 60 fps is most often used for slow-motion video. A video is shot at 60 fps and then slowed down on a 24 fps timeline, resulting in a 2.5x slow-motion effect. 60fps can also be used when there is a lot of fast action.

Even higher frame rates like 120 fps and 240 fps may be possible on specific video cameras and can be used to slow down footage even more for dramatic effect.

Experiment With Shutter Speeds

The 180° Shutter Rule is a good starting point for setting the shutter speed for your video projects and works nicely in many scenes. However, I encourage you to experiment with faster and slower shutter speeds in your video projects to understand how they affect the look and feel of your footage and how they can be changed to achieve creative looks.