Rolling Shutter Effect [Complete Guide]

Whether you’re a content creator or professional cinematographer, you may have heard about the rolling shutter effect. Perhaps you came across this article because you want to prevent or fix it in one of your videos. This article will help with both of those needs!

So, what is the rolling shutter? The rolling shutter effect is a phenomenon in videography in which fast-moving objects appear skewed or distorted when recorded by a video camera. This happens because the camera records different parts of the frame at different times, rather than capturing the whole image at once.

For those curious, the rolling shutter artifacts occur due to the sequential method that a typical video camera uses to capture images. As opposed to photography cameras, which can capture an image all at once, many video cameras capture the frame line by line, moving from top to bottom. This means different parts of the frame can have slightly different timestamps. This doesn’t usually affect the overall recording, unless that which the video camera captures is moving extremely fast, like the rotor blades of a helicopter. However, it can also occur to slow-moving subjects when the camera (or camera person) shakes or trembles, like on many amateur smartphone video recordings.

To break it down further, consider this example. If you're filming a helicopter in flight, you aim to capture the rapid spin of the rotor blades. However, due to the rolling shutter effect, instead of perceiving the blades as a circular blur of motion, you might see them as disjointed or warped lines in your video. This distortion happens because as the camera scans the scene line by line from top to bottom, the rotor blades have moved slightly during that time. So, each line of the frame has a slightly different timestamp, leading to this unwanted look.

The rolling shutter camera effect occurs from the way digital video cameras read data off the sensor. The sensor is meant to convert an optical image into an electronic signal, essentially capturing the light information to create the video or image. It scans the scene vertically from top to bottom, so all parts of the image are not recorded at exactly the same time. This can lead to:

• Rolling shutter distortion. Fast-moving objects or a quickly panning camera can cause straight lines to appear curved or skewed. Think of a helicopter blade that appears bent or skewed on video.

• Distorted proportions. Rapid movement can stretch or compress objects, altering their perceived shape and size. A fast-moving car, when captured on video, may appear to be stretched upward and backward, if the rolling shutter effect is not prevented or fixed.

Think of filming a helicopter taking off – the rolling shutter effect can make the helicopter seem elongated, or the ground appear to stretch unnaturally.

The camera rolling shutter effect becomes most noticeable under the following conditions:

• Fast camera panning or tilting. This could occur when one tries to capture a panoramic view of a landscape or film a fast-paced sporting event in which the action constantly moves around the field.

• High-speed objects passing across the frame. This is common when recording vehicle traffic from a fixed position, in which vehicles zoom past quickly, or when filming sports like racing, golf, or football.

• Rapid light changes, like flashes. This often happens during concerts or parties, where stage lights or strobe lights flash intermittently. It could also occur during a lightning storm.

• Shaky hand-held recording. This is a common issue for amateur videographers who might not have stabilizing equipment, or when one records footage while moving, like filming a selfie video while walking.

While it's not feasible to completely eradicate the rolling shutter effect if your video camera has a rolling shutter, certain best practices can help mitigate its impact:

• Use a tripod to reduce camera shake. Providing a stable base for your camera helps to eliminate minor tremors and shaking, often the case while capturing high-speed objects, such as a speeding train or a helicopter soaring in the sky.

• Avoid panning or tilting too quickly. Rapid movements can exacerbate the rolling shutter effect. If you're capturing a fast-moving sports match or following the path of a bird in flight, it's essential to maintain a slower and smoother movement of the camera.

• For moving subjects, try to match their speed and direction. If you're shooting a moving subject, like a cyclist or a low-flying airplane, attempting to keep pace with the subject can help reduce distortions. However, this may require more advanced filming techniques and equipment.

To prevent it completely, you may consider using video cameras with global shutters or faster shutters, if possible. Global shutter cameras capture the entire frame at once, reducing the likelihood of rolling shutter distortions. Keep in mind, however, that these technologies can significantly increase the cost of your equipment.

Addressing rolling shutter distortion in post-production is another way to tackle this issue. Many modern video-editing tools offer video stabilization features and rolling shutter correction. Some even harness the power of AI to analyze the video’s frames and provide adjustments and corrections. In other cases, a video editor could adjust the frame rate of the video to see whether it makes a visual difference.

Movavi Video Editor, for instance, offers a powerful stabilization feature that can correct shakes and jitters, providing smoother and more professional-looking videos. It has the ability to analyze the video, frame by frame, and make necessary adjustments to reduce the distortion.