What's the Deal with Global Shutters?

If you read that headline in a Seinfeld voice, we should be friends. But seriously what's the deal with Global Shutter? If you've been following photo gear news you may have seen a whole bunch about the new Sony A9III and its brand-new global shutter.

Chances are you had one of two reactions. Either "Huh, what's so cool about that?" or, "HOLY CRAP HOLY CRAP HOLY CRAP! IT'S HAPPENING!" So if you are in the first camp, well I'm here to help. If you are in the second camp, well later in the blog I might dash your hope just a little bit.

Rolling Shutter vs. Global Shutter 

So first, let's talk about the kind of shutters (and by shutters we really mean sensors) we have in nearly every camera on the market. Nearly every photo, video, and cell phone, camera of the last decade has used a rolling shutter. What that means is the image is captured, line by line, from top to bottom. That means that the top of the image is just slightly older than the bottom.

This causes all kinds of problems you've likely faced, banding, vertical lines being crooked, and slow flash synch speeds. Now to be clear, this isn't just a digital photo problem. These problems have been an issue for any camera with a physical shutter, yes including film cameras. 

Now global shutters, sensors that capture all pixels at the exact moment, have existed for decades. If you ever had a CCD camera you had a global shutter. However, the quality and processing power made them pretty impractical, especially as digital photography and filmmaking took off. Rolling CMOS sensors were easier to produce, required less processing power and allowed image quality to be much better.

It was particularly great for the new DSLRs because the rolling sensor worked so similarly to the focal plane shutters in use at the time, that any drawback of the sensor was the same drawback with the shutters as well. So photographers had no meaningful drawbacks, and had increased quality, along with a reduced cost. It was a win-win.

Global Shutter Sensors Today 

Now global sensors haven't gone away, many companies tried to innovate. But the limitations were still there. It just hasn't been practical to keep up with the increased image quality standards. And as global sensors got better, rolling sensors got EVEN BETTER, and as readout speeds increased those rolling shutter issues became fewer and far between. And to this day (I will talk about Sony in just a sec) global sensors tend to offer less dynamic range, low light sensitivity, and overall image quality, than similar rolling sensors, in addition to requiring MUCH more processing power.

Enter Sony...

So how have they overcome these limitations? The obvious answer, and maybe the most correct answer is money. The Sony A9 III's jump in price isn't just inflation, this is significantly more money than the previous generation. The more complicated answer though is, have they? Truthfully, we don't know. No one has been able to open the raw files. No one has been able to do any real tests of the image quality from the camera. It's sharp, sure, and it makes good-looking JPEGs, but in all likelihood, there could be some compromises. We already know the lowest ISO the camera has is 250, while not necessarily a problem, it is interesting.

example image sony a9 iii

Image taken with Sony A9 III | Provided by Sony 

They could be following in the footsteps of Red and the Komodo. The Komodo has a global shutter, but has a noticeably lower dynamic range compared to the other Red cameras, clocking it at just a hair over 12 stops. But has that stopped it from being a massive hit with Hollywood and consumers alike? Heck no. And seriously, it's a solid camera.

And by all accounts, the A9 III looks like it can do some amazing things. As a filmmaker, being able to move the camera intensely, do whip pans, and shoot fast action is a big deal. And for photographers, getting that super crisp slice of time at incredible speeds is nothing short of astounding. That's where I think the A9III is going to soar, those photographers who need that speed and precision. For those shooting portraits in a field, shooting your family on vacation, or even studio product stuff, the A9III doesn't really offer anything you need.

Do I Need A Global Shutter?  

Now technology does tend to trickle down, so it's likely that we will see this tech spread, but in truth, it doesn't need to. Rolling sensors work great for a lot of things. Unlike switching to mirrorless, I don't think we are going to see a complete switch in the next decade to global sensors because there simply is no need. Certain professionals will switch, and filmmakers will definitely switch once the quality is good enough, but for most people and many professionals rolling sensors will have no drawbacks but offer the same or better quality.

So don't worry, your camera has not become trash overnight. Working professionals from every level of the industry will still be using rolling sensors, the industry isn't changing, there are just more options. And while I have NO INSIDER INFORMATION, I assume Canon has a global sensor coming, or in the works, and Nikon will get one just as soon as Sony's done with it ;)

What are your thoughts? 

Thanks for reading, and don't forget to take your camera out today!

Global shutter

1 comment



I would disagreed that there is not a need for a global shutter with a low iso capability. I Photograph architecture and use strobes. The problem I have is that on a bright sunny day I am limited by the rolling shutter to 1/200th of a second. This means I have to use significantly more power to reduce the heavy shadow effect than what is available today on the market. And I am referring specifically to battery operated strobes not 110 V units. The only way to achieve 1000 watts, which we sometimes require, is to double up strobes, and this means increasing the number of lights we must carry. High speed sink is not an option so a global shutter with an iso of 100-200 would be great.

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