When shooting a video,
you have probably heard a lot about shooting at a 180-degree shutter angle. So, when shooting at 24p,
the shutter speed is set to 1/48, and at 30p, it's 1/60 second, and at 60p, it's 1/120 second. Today, we will explore how this shutter speed
affects the video and whether we always need to adhere to the 180-degree shutter angle. Let's find out where the term shutter angle
comes from. In the past, with cameras using film,
there was a circular disk that could be rotated to control
how much light passes through between the lens and the film
when light enters the lens and reaches the film,
an image is created. Generally, in these old film cinema
cameras, the shutter mechanically could open from around 11 degrees to a maximum
of 180 degrees, and in recent digital
cinema cameras, the shutter

You can adjust the angle up to 360 degrees. In the case of digital cameras, instead of a mechanical disc, the sensor adjusts the time to collect light for each frame to determine the shutter speed. Looking back at a mechanical shutter, for example, if it is set to 45 degrees, as it rotates in a 360-degree circle, only 45 degrees will open, and the rest will block the light. Since it opens for a brief moment, the exposure is shortened, meaning a very short moment in the frame is stopped and recorded, ultimately resulting in less motion blur in the image. Therefore, each frame shot with a 45-degree shutter angle will produce sharp and detailed images. On the other hand, assuming there is a shutter disc that opens up to 360 degrees, each frame will be exposed to light for a much longer time, leading to increased motion blur.

So, at the intermediate level,
the exposure time is set at 180 degrees shutter angle, and giving this amount of exposure time per frame will make motion blur appear most naturally to the human eye. If we calculate, in a 360-degree circular disc where half is open, we call this a 180-degree shutter angle, and when multiplied by the frame rate, it results in a shutter speed of 1/48 seconds. In video, we see consecutive still frames. So, if the frame rate is 24p, 24 still images are played sequentially per second, creating the illusion of movement. For example, if I am currently shooting at 24p with a shutter speed of 180 degrees, matching 1/48 seconds, and I shake my hand while checking each frame, this kind of motion blur is added, creating a natural video. If the shutter speed is too fast,

When the motion blur decreases like this, it feels like the video becomes rigid and unnatural. On the contrary, if it's too slow, there will be a lot of motion blur. In cases with a lot of waterfall-like movements, the difference in shutter speed becomes noticeable. Currently, at 1/50 seconds, it looks natural, but at higher shutter speeds, the motion blur almost disappears, making it look unnatural. Conversely, if it's too slow, there will be too much blur. That's why most cinema cameras can be set not by shutter speed but by shutter angle, and you can change the frame rate without having to change the shutter speed manually. So, Sony FX3, please do a firmware update quickly. Why aren't you doing it?

Hurry up so normally, by keeping the 180-degree rule, we know that it is good to shoot. In bright environments, people are well aware that using an ND filter is necessary to secure the shutter speed and aperture. So, action cameras like GoPro and drones are the same. To obtain a more natural motion blur, you can use an ND filter set. However, it is not necessary to shoot like this all the time. As you just saw, you can change the mood of the video with the shutter speed. Taking movies as an example, there is a representative one like Saving Private Ryan. When landing on the beach for a mission, to create a tense feeling, they shot it with a 45-degree angle, so it was almost shot at 1/200 seconds. Therefore, even the smallest details like flying debris and bullets passing by are visible.

The motion blur has been reduced, so the sense of realism and tension has increased significantly in the video. Therefore, in order to express the suspenseful atmosphere, such as chase scenes in movies, this fast shutter speed is often used. On the contrary, slow shutter speeds are also frequently used. When used slowly, it naturally incorporates a lot of motion blur, so it can be used to create scenes with a dreamy or surreal atmosphere. For example, in The Usual Suspects, there is a scene where the protagonist recalls something, and a very slow frame rate of 6 frames per second, with a 360-degree angle, in other words, a slow shutter speed of 1/6 of a second, was used. Also, in The Wolf of Wall Street, such scenes were expressed by using a slow shutter speed of 1/12 of a second to depict the protagonist's state.

Now, let's look at some more practical aspects. I am currently shooting with an ND filter set to 1/48 second, 180-degree shutter angle. There is no movement happening right now, neither in the foreground nor in the background. Should I still strictly adhere to the 180-degree shutter angle in this situation? Let's test it. Let's remove the ND filter and increase the shutter speed to 1/1000. Can you see any differences? Of course, it might look a bit unnatural when there is sudden movement. Let's try raising it further this time. I increased the ISO and shutter speed. This time, I raised it to 1/5000 second. Do you notice any differences? So, when shooting with a fast shutter speed in situations where there is minimal movement, it often doesn't look awkward.

In this kind of situation, there is no need to panic because you lack ND filter density or forgot to bring an ND filter. The second situation is when using a camera without image stabilization, such as shooting handheld with a Blackmagic Cinema Camera and planning to correct it in post-production. In this case, it is better to set the shutter speed slightly faster than 180-degree shutter angle. This is because if there is a lot of motion blur, it will naturally look more shaky, making the correction more challenging. Also, when there is slow motion involved, shooting at normal frame rates like 60p, 120p, or 240p instead of true slow motion, there are times when you need to slow it down. In these cases as well, setting the shutter speed slightly faster than the 180-degree shutter angle is recommended. The reason is that slowing down in editing means creating new frames.

It's a task that is inserted intermittently. So, in these cases, adding motion blur to each frame makes it easier to create a new image and the result also appears more natural. Lastly, when flickering occurs, you should adjust the shutter speed. Typically, flickering can occur when LED lights are synchronized with the shutter speed, but cameras have an anti-flicker - variable shutter speed control to prevent this. By using this, you can finely adjust the shutter speed to prevent flickering while staying close to a 180-degree shutter angle. Understanding these aspects of shutter angle and speed can be helpful in creatively utilizing them for video shooting. I hope this information will be useful. Then, I will see you in the next video. Thank you!

룰은 깨라고 있는 거라고 - 180도 셔터 앵글(개각도)

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