Shutter speed is a principle element of photography and filmmaking alike; it is one of the core components of each art form, and it is also one of the most confusing aspects.
If you’re an auditory learner, you can find entire contents of this article in the video tutorial below.
[dropcap]S[/dropcap]hutter Speed History
Shutter speed is the term used to describe the amount of time that each individual frame is exposed for. In filmmaking, the number will always be a fraction of a second. The most commonly used shutter speed for filmmaking would be 1/48 or 1/50. This would mean that each individual frame passing in front of the sensor (figuratively speaking) is being exposed for 1 48th of a second
The higher the shutter speed, the less amount of time the frame is being exposed. The lower the shutter speed, the more time the frame is being exposed.
However, you may notice a difference in how your footage reacts to different shutter speeds. For example, the two shots below were shot at a shutter speed of 1/50 and 1/200 at 24fps. When the footage is paused and zoomed in at 200%, you may notice a difference in the clarity of the subject as he is about to stand up.
At 1/50th of a second, the subject is blurred
At 1/200th of a second, the subject is viewable.
As 1/200 shutter speed is exposing the frame for less amount of time, the blur is negated.
This is where it can become confusing for new filmmakers and photographers. 200 is a larger number than 50, and because of this, it would seem that you would be exposing your image longer with the numerical value of 200. Instead of thinking of these numbers regarding length, think of them as speed; going 200mph is faster than 50mph.
So why does a shutter speed of 1/50 make images blurred?
In real life things rarely take a second to complete; moving your arm to catch something falling off the shelf, pulling the trigger button down on your game controller to shoot the enemy, jumping over a wall, whatever it may be, happens within a fraction of a second. This is why images are more blurred with a slower shutter speed.
As a rule of thumb for smooth cinematic action, the shutter speed should be double your frames per second. Therefore for a cinematic look, your frames per second should be set at 23.986, or 24 fps if your DSLR does not allow for 23.986. For the cinematic look, your shutter speed would be double which would be 1/48. However, many mid-range DSLR’s and even some high-end DSLR’s don’t allow for 1/48, so 1/50th of a second is just as acceptable. Some DSLRs will give you a whole number instead of a fraction, keep this in mind that are you still shooting slower than a second.
[dropcap]W[/dropcap]hy do we need to do this? What use does this information provide? This is because of the shutter angle.
Shutter Angle, is the term used to describe the speed relative to the frame rate. Camera Company RED says:
The term is a conceptual relic of rotary shutters where a disc with an angled opening would spin and let in light once per revolution to expose each frame. In layman terms, Every time the frame advances the shutter rotates and exposes that frame.
So how do you work with a shutter angle?
Here we have an 180-degree shutter, a 90-degree shutter, and a 45-degree shutter based on the rotary shutter design.
On an actual celluloid camera, there would be an advancement frame advancement for every rotation. Each frame is being exposed for a different amount of time,
The larger the angle, the slower the shutter speed, the more motion blur,
The smaller the angle, the faster the shutter speed, the less motion blur,
As stated earlier, it was a rule of thumb to have your shutter speed double [180 degrees] the value of your frame rate. The question; why? Any larger, and motion appears more smeared, as the end of blur in one frame extends closer to the start of the blur in the next frame. Any smaller and the motion appears more stuttered and disjointed since the blur gap increases, causing frames to become more like discrete images.
The term shutter angle doesn’t necessarily apply to many current cameras, say for example the camera on your iPhone doesn’t control shutter in this way as there is no rotary shutter disk. In fact, a lot of DSLR’s have a focal plane shutter.
All that has happened is angle terminology has stayed the same throughout the technology progression. It simply describes the appearance of motion blur in video.
How do we work out the math for other angles and shutter speeds which aren’t the generic 180 1/48th of a second?
Let’s say we want a 45-degree angle to heighten the action and make everything crisp. Remember a smaller angle is a faster shutter speed. Cinematographer Janusz Kamiński used this in Saving Private Ryan to help bring the aesthetic of war to the film.
So we would take our frame rate, 24fps, now we need to work out how to get from 360 degrees, which is full exposure, of a frame to 45. 360 divided by 45 is 8. Now we take that 8 and times it by our fps, which is 24, letting us know that our shutter speed needs to be 1 over 192.
Here’s a cheatsheet for the majority of shutter angles when shooting at 24 frames per second.
We know about shutter speed, and we are aware of shutter angle, the most important thing as always with filmmaking; how do we use this knowledge to help tell our story?
As mentioned previously Janusz Kamiński used a small shutter angle for a staccato look in Saving Private Ryan.
In an interview Steven Spielberg said:
You can also see several explosions, and Janusz came up with the idea of shooting with the shutter open to 45 degrees or 90 degrees, which completely negated any blurring. Often, when you see an explosion with a 180-degree shutter it can be a thing of beauty, but a 45-degree shutter looks very frightening.
So what about the opposite effect, what if we lower our shutter speed and widen the angle? This would create the effect as if the character is currently dazed or experiencing some sort of poison [See video tutorial]. No post production effects. All in camera. You should now understand what shutter speed does, how shutter angle works, and how you can use them to enhance your story.