Shutter Speed

What is a Global Shutter – How It Works

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Written By Nate Torres

As your experience grows as a photographer, you will eventually dive into the technical side of photography.

This is where you may encounter the term, global shutter.

Well in this article, I’ll be diving into what a global shutter is, how it works, and lots more.

Let’s dive in!

What is a Global Shutter?

The global shutter is a type of shutter mechanism that captures an entire image in a single instant, freezing all the action with the frame simultaneously.

This means that every pixel on the sensor is exposed to light simultaneously, ensuring a precise representation of the scene.

An analogy I like to think to think of is with a theater.

Imagine you’re sitting in a theater, eagerly awaiting the start of a captivating stage performance. The curtains are drawn, and the spotlight is about to illuminate the stage.

In this analogy, the stage represents the camera sensor, and the spotlight represents the exposure of light onto the pixels.

Envision a grand moment where the entire stage is instantly flooded with a bright, steady light.

In this case, every element of the performance, every actor, every movement, and every detail is captured simultaneously.

The result is a synchronized depiction of the entire stage, capturing a complete snapshot in a single instant.

global shutter theater analogy
global shutter theater analogy

To better understand global shutters, let’s dive into how they work.

How Do Global Shutters Work?

In order to better understand how global shutters work, we must take a closer look at the camera sensor.

There is a lot of technical jargon such as memory cells and photosensitive elements so I will do my best to simplify how it works for you.

In short, a global shutter in a camera works by capturing an image all at once, like taking a picture with all the pixels on the sensor at the same time.

Each pixel has a special part that stores its initial state before the exposure begins.

When light enters the camera, it changes the electrical charge in each pixel.

After the exposure, the camera reads the charge in each pixel and turns it into a digital value representing the brightness of that pixel.

camera sensor
camera sensor

Now that we know how a global shutter works, let’s take a look at a global shutter’s counterpart — a rolling shutter.

The Counterpart of Global Shutters

When discussing global shutters, it’s necessary to look at their counterpart, the rolling shutter.

A camera with a rolling shutter mechanism has a sensor that scans the scene from top to bottom or left to right.

cmos sensor rolling shutter
CMOS sensor scanning up and down

While this is an effective method, it can introduce a distortion in your image called a “rolling shutter effect.”

It’s also important to note that global shutter sensors are often associated with CCD sensors while rolling shutter sensors are often associated with CMOS sensors.

Going back to the analogy of a theater I gave earlier, think of the rolling shutter as a narrow strip of light that slowly moves across the stage, revealing different parts of the performance one section at a time.

As the strip of light progresses, you catch glimpses of the actors, their movements, and the overall scene.

However, if there’s fast-paced action happening on stage, you might notice distortions and inconsistencies as each section is revealed at a slightly different moment in time.

There are many advantages and disadvantages to using a rolling shutter vs a global shutter, so I recommend you check out the guide I wrote covering this topic.

What Cameras Have a Global Shutter?

If you read my guide on rolling shutters and how they differ from global shutters, you may have remembered that rolling shutters are the more common camera sensor these days and are used in most digital cameras, action cameras, and smartphones.

With that being said, what cameras use a global shutter?

1. Industrial and Scientific Cameras

One category of cameras that often incorporates global shutters is industrial and scientific cameras.

These cameras are utilized in fields such as machine vision, scientific research, and industrial inspection, where the ability to freeze motion and capture accurate representations of fast-moving objects is paramount.

Manufacturers like Basler, Teledyne DALSA, and FLIR Systems produce industrial cameras with global shutters to cater to these specific applications.

2. Professional Video Production

Where else may they use cameras with global shutters? Hollywood!

All kidding aside, another domain where global shutter cameras find their footing is within cinematography and professional video production.

The demand for capturing high-quality footage with minimal distortion during fast-paced scenes has led camera manufacturers to integrate global shutters into their cinema camera offerings.

Industry-leading brands such as ARRI, RED, and Sony have introduced cinema cameras with global shutter capabilities, providing filmmakers with the means to capture smooth and accurate motion without rolling shutter artifacts.

red komodo global shutter
RED – KOMODO 6K has global shutter

It’s important to note that global shutter technology is still evolving and expanding its presence across different camera types and price ranges.

While not all cameras currently on the market feature a global shutter, advancements in sensor technology and camera manufacturing techniques continue to pave the way for wider adoption in the future.

Speaking of price ranges, if you take a look at some of these cameras you may have noticed their hefty price tags — why is that?

Why is Global Shutter So Expensive?

One common observation is that cameras with global shutters often come with a higher price tag compared to their rolling shutter counterparts.

Several factors contribute to the higher cost associated with global shutter cameras.

Let’s take a look at those factors:

1. Sensor Complexity

The first factor that causes global shutters to be more expensive is due to their sensor complexity.

Implementing a global shutter requires a more complex sensor design compared to a rolling shutter.

Global shutters require additional circuitry and memory cells within each pixel to store and read the light exposure accurately.

This increased complexity adds to the manufacturing costs of the sensor, resulting in a higher overall price for the camera.

2. Manufacturing Challenges

The second factor that causes global shutters to be more expensive is due to their manufacturing challenges.

The process of manufacturing sensors with global shutter capabilities is more intricate and demanding.

The production of sensors with precise memory cells and readout mechanisms can be more time-consuming and resource-intensive, leading to increased manufacturing costs.

These additional challenges and requirements in the manufacturing process contribute to the higher price of global shutter cameras.

3. Lower Demand and Limited Availability

The third factor that causes global shutters to be more expensive is due to their lower demand and limited availability.

Global shutter technology is still relatively niche compared to rolling shutter technology.

The demand for global shutter cameras is not as widespread, which affects economies of scale in production.

Manufacturers, therefore, produce a limited number of global shutter cameras, resulting in higher per-unit costs.

Limited availability and lower demand can drive up the price of these specialized cameras.

4. Market Positioning

The fourth factor that causes global shutters to be more expensive is due to their market positioning.

Camera manufacturers often position global shutter cameras as high-end or professional-grade equipment, targeting specific markets such as industrial imaging, scientific research, and professional cinematography (as mentioned earlier).

By positioning global shutter cameras as premium products, manufacturers can command higher prices based on their advanced features, capabilities, and target audience.

5. Research and Development Costs

The fifth factor that causes global shutters to be more expensive is due to their research and development costs.

The development of global shutter technology involves substantial research, engineering, and innovation.

Companies invest significant resources in developing and refining the technology, which is then reflected in the price of the final product.

The costs associated with research and development are passed on to consumers, contributing to the higher price point of global shutter cameras.

Final Thoughts

In conclusion, the global shutter stands as a remarkable innovation in the realm of image capture, revolutionizing the way we photographers and videographers freeze moments in time.

As the field of photography continues to evolve, I hope global shutter technology holds the promise of becoming more accessible and widespread, offering new possibilities for creative expression and visual storytelling.

Frequently Asked Questions

How do global shutters work?

Global shutters work by simultaneously exposing and capturing an entire image in a single instant, ensuring that every pixel on the camera sensor receives light at the same time, resulting in accurate and distortion-free representations of the scene.

Do any cameras have a global shutter?

Yes, certain cameras, such as industrial and scientific cameras, some cinema cameras, and select medium format digital cameras, are equipped with global shutters to provide precise motion capture and eliminate rolling shutter artifacts.

Does GoPro have global shutter?

No, GoPro cameras do not have global shutters as they typically utilize rolling shutter technology for image capture.