Sony Made a Global Shutter Camera: What is That and What Does it Mean For the Future of Photography?

In early 2024, Sony is releasing the new A9iii which features a full-frame global shutter. Many people are talking about and getting excited for this. As a photographer, I wanted to know more about the real benefits and drawbacks of a global shutter to understand what it actually offers for photographers. Here, I’ll go over what a global shutter is, how it behaves differently to rolling shutters, and will discuss if having this is worth the extra asking price or if its just hype.

Rolling Shutters and Their Issues

A camera sensor is essentially a grid of pixels that get exposed to light. The data collected from this is processed and turned into an image. In most cameras, they use something called a rolling shutter. A rolling shutter reads pixels out similarly to the way you would read a paper: sequentially top to bottom. This is even true with contemporary mirrorless cameras that have electronic shutter functions. While, the read out is very fast, especially when using a stacked sensor, it is not instant, and can create some unique issues with fast camera movements and subjects.

If you’ve ever seen a video of a propeller or fan and the blades look like they are being warped, breaking the laws of physics, or straight lines turned diagonal when the camera is moved quickly, that is a result of a rolling shutter. The object is moving faster than the pixels can be read. You are essentially seeing a delay between the top and the bottom of the image. This effect can create some truly strange results and gets expressed virtually any time you are taking video of a fast moving object. Here is a video that really allows you to visualize the rolling shutter effect and see why it creates these strange-looking results: LINK

This is not to be confused with aliasing, which is another concept that causes the videos you may have seen where fast moving objects appear to be completely stationary or even moving the wrong direction like spinning car wheels or helicopter blades. That has more to do with the frequency of the camera syncing up with the speed of the object. Here is a video that explains the difference between the 2: LINK

What is a Global Shutter?

The Sony A9iii works a bit different. As opposed to a rolling shutter, a global shutter exposes every pixel on the sensor at the same time. This will obviously eliminate any warping on fast-moving objects in videos, but you may be wondering, why is this a big deal, is it worth putting global shutters in new cameras, why isn’t this in every camera already, and does this really matter for photography? The answer is not as straight forward as a simple yes or no.

A global shutter is not a new concept. They have existed on high-end cinema cameras for a while to address the warping mentioned above. The new Sony camera shows that this technology can be put in the hands of smaller creators, but there is a reason this hasn’t happened until now. It is expensive and hard to do. It is a lot of data to capture, process, encode, and output all at once. Many modern cameras also are intended to take both high-quality photos and videos, meaning higher and higher megapixel sensors for photos and even more data that needs to be dealt with very quickly.

Until the processing speed of cameras and cards catch up, global shutter sensors typically have less megapixels to compensate. I am a firm believer that more megapixels does not equal better photos however. I shoot on the Canon R6, which has only 20 megapixels and I believe that lower amount actually provides some great benefits while the tradeoffs would only really be a problem if I intended to print up something like a billboard. So assuming 25 megapixels is enough for you, here’s why you might want a global shutter over a rolling shutter camera.

Why You Might Want a Global Shutter Camera

If you are mostly doing video work, but don’t want a cinema camera so you still have the option for photos, a global shutter will make your horizontal pans not distort, and keep fast moving objects from warping in weird ways. Great! But as a photographer, why would you want or need a global shutter? In most cases, you don’t. If you are photographing fast paced action like sports, or are constantly running into banding issues around cheap led lights, this might be worth considering. Led lights are not constantly on, they flicker on an off quickly. This flickering shows itself on a rolling shutter as dark horizontal stripes across your photo, indicating the times when the light flicked off and back on again as the sensor was being exposed top to bottom. A global shutter will not run into this issue and certain things like a swinging golf club will still look straight rather than bent like crazy.

There is another aspect where having a global shutter could be very useful for a photographer and that is when doing flash photography. Those of you who have used a flash before will know this, but there is a limit to how fast your shutter speed can be when using a flash before not all of your frame will be lit up by the flash. This is caused by your shutter speed being so fast, that by the time your flash has fired, the shutter curtain has already have covered part of your image (pixels have already been read on an electronic shutter). You have to switch your flash over to high speed sync mode to use faster shutter speeds on a rolling shutter. This causes the flash to behave differently (it fires multiple times at a lower intensity) and effectively reduces the amount of light it can output. To learn more about this concept click HERE. With a global shutter, there is no shutter speed limit and no need for high speed sync. You can freely play with shutter speeds to get the exposure you want and the flash will still reach all parts of your image.

You can decrease your shutter speed until you start getting faster than the actual flash duration (the amount of time the flash is on for when it fires) at which point if you continue to decrease it, the effective power of the flash will be reduced, but there won’t be any crazy banding or shutter curtains present in your photo. If you want to learn more about flash duration and how it affects your images, click HERE.

To Summarize

In conclusion most photographers will not need what is offered from a global shutter. If you do a lot of natural light shooting not including high speed sports, or your flash photography is typically confined to a studio setting, I do not think a global shutter will offer you enough benefits to justify the cost. That being said, it is a cool addition for a camera like this and I believe that this may be the beginning of global shutters being implemented into new future cameras from every camera brand. As the readout and processing speed of cameras is improved, these will likely become cheaper to make and more readily available. Not to mention, offering a global shutter mirrorless camera was a huge marketing win for Sony, I’m sure other brands will be scrambling to capitalize on this as well. As a video content creator, it may be worth it for you to get a global shutter camera. For photographers, unless you’re in a niche that will get a lot of value out of the benefits, it’s probably not worth upgrading to this until there are other reasons to get the camera over the global shutter alone.

Thanks for reading, I hope this was helpful.