At some point in the last 10 years, there has been a seismic shift in the mirrorless vs DSLR debate. The tide has turned, and now the mirrorless camera is rising in popularity and demand.
When I was making the shift to professional photography, I asked my friend and lifelong pro Stuart Boreham what he thought of mirrorless cameras. “I don’t,” was his succinct reply.
Well, things have changed. But you might still be wondering what is the best way forward for your gear. Should it be mirrorless or DSLR? To take the stress out of it for you, we’ve put together this guide to the differences. We’ve looked at the history of the two formats, and we’ve examined the pros and cons of each.
We think the future is mirrorless, but for some people the answer might still be DSLR. After this article, you’ll know which is right for you.
Mirrorless vs DSLR: What Is a DSLR?
The Twin Lens Reflex Camera
A Digital Single Lens Reflex (DSLR) camera is the direct, digital descendant of the Single Lens Reflex camera (SLR). And those are called “Single” lens reflex because they followed the Twin Lens Reflex camera, most famously made by Rollei.
When you use a TLR, you look down into the viewfinder. The top lens projects an image via a mirror (hence “reflex”) onto a ground glass screen. The bottom lens captures the image onto the film.
The advantage of the TLR is that you get to look at the viewfinder rather than through it. It helps composition. The film also gives a 2 1/4″ (6 cm) square image.
The disadvantages are many. The image in the viewfinder is reversed, so you have to learn to pan left when you want to move right. They aren’t great in bright sunlight. And to focus accurately, you might need to flip out the magnifier to check that everything is correct. Plus, as you get closer to your subject, parallax error creeps in.
The Single Lens Reflex Camera
These problems were eliminated over time by the development of the SLR. It’s a combination of some pretty amazing engineering and technology. But if you want to use one lens for viewing and shooting, you need some clever solutions.
Two things are essential for an SLR to work. A moveable mirror that swings up out of the way when the shutter fires and a pentaprism.
The mirror, angled at 45 degrees, sends the image to a ground glass focusing screen and then to the viewfinder. When the shutter is pressed, it rapidly swings up out of the way, allowing light to reach the film. Then it returns to the starting position.
The pentaprism bounces the image from the focusing screen off two surfaces and directs it to the viewfinder. That process sends the light in the same direction as it was originally traveling. In the process, it corrects the image reversal so the viewfinder sees the scene as it actually is.
It’s a slick operation. Take the flagship Canon EOS 1-V, their last great SLR. It could shoot at 10 frames per second (fps). That’s the same speed as your blink reflex.
In that incredibly short time, it flips up the mirror, opens and closes two shutter curtains, and closes the iris to the required aperture. Then, it returns the mirror to the starting place, opens the aperture, and winds the film onto the next frame. Incredible.
The current Canon DSLR flagship, the EOS 1D Mark III, shoots at 16 fps. That’s partly because it doesn’t have to wind the film. For a DSLR, it’s pretty much the limit of what is possible physically and mechanically. You can lock up the mirror and shoot at 20 fps in Live View mode. But that’s your limit.
But then innovations came along. Through-the-Lens (TTL) metering meant you could set the exposure while looking through the viewfinder. At first, you had to stop the lens down to do this, making the image dark in certain circumstances.
Eventually, it became possible to overcome that. Autofocus came along, and fancy innovations like semi-silvered mirrors allowed metering and focus. My last Canon SLR even had eye-controlled focus.
The Arrival of the DSLR
Then it became possible to make camera sensors of high enough quality to be put in an expensive camera. And that meant the Digital SLR arrived, and the age of the DSLR was born!
It’s worth noting that the first Canon pro-level DSLR, the EOS 1D, had a 4.15 MP sensor. That’s laughable in today’s terms. But, the revolution had happened. The DSLR gradually replaced the SLR in every area of use.
There were many advantages to digital. Obviously, you could take many more photos than the 36 allowed by 135 film. (There was a curious bulk film back available for some pro SLRs that gave up to 750 shots on a 100m roll of bulk film, but that was clearly an exception.)
With digital, you can see the result immediately and adjust accordingly. Eventually, DSLRs outgunned SLRs in every aspect. But it was a while before they made an impact on the professional market.
Sony blazed the trail with their Alpha 7R in 2013. But it was five more years until the heavyweights of pro photography, Canon and Nikon, followed suit. The following five years established the mirrorless camera as not just a viable competitor but increasingly a superior beast.
Mirrorless vs DSLR—What Is a Mirrorless Camera?
Apart from (D)SLRs, pretty much every camera is “mirrorless.” So it seems a little odd to describe one particular style of camera as mirrorless. But it’s shorthand for an interchangeable-lens camera that relies on electronics to show the user what is being framed in the shot.
Types of Viewfinders
There are two main approaches to letting the user see the image being framed. Pretty much every mirrorless camera has a screen for viewing the images. And some have an electronic viewfinder (EVF) as well.
An EVF is basically a small screen that you look at through an SLR-style viewfinder. There are advantages over what you get with a DSLR. For one thing, you can see the real-time effects whenever you adjust your exposure.
There are other advantages. Modern camera sensors are amazingly sensitive in low light. This means you can see things through an EVF that are near-invisible through a DSLR viewfinder.
There are some shortcomings, though. Because it is a screen, there is some lag in the image. As technology improves, this becomes less of an issue. And it’s most noticeable when the camera, subject, or both are moving quickly.
The best mirrorless cameras reduce these issues to a negligible minimum. But it’s something to consider when comparing the two types of cameras. One reason for using the EVF actually has little to do with how we see things.
There’s no doubt that the traditional photographer’s stance is second only to a tripod for stability. Elbows in, one hand under the camera, and face pressed to the camera as you look through the viewfinder is impossible to achieve with a viewfinder-less camera.
On the other hand, the EVF adds bulk. One advantage of the mirrorless camera is that it can be more compact than its DSLR cousin. As with all things concerning camera gear, it’s a tradeoff of features. We all have to choose what is the balance for our needs, wants, and budget.
Mirrorless Camera Shutters
There are some areas where mirrorless cameras have left the DSLR way behind. One is in drive speed, which is also called “burst rate” and is measured in frames per second (fps). This “frames per second” measures how many shots a camera can take per second in burst mode.
As we saw earlier, the shutter in a DSLR does a lot of very fast, precise mechanical actions. And there are limits. You can make a mirror mechanism faster by making it lighter. But at some point, you reach the physical limits.
A mirrorless camera only has to focus on the shutter itself. Most high-end mirrorless cameras offer both a mechanical shutter and an electronic one. The former is likely to be a focal-plane shutter. Two “curtains” move across the aperture at the back of the camera in front of the sensor. The gap left between these two curtains determines the shutter speed. It’s a feature left over from SLRs.
The focal plane shutter is fast and reliable. It has the disadvantage of limiting flash sync speed. And in most cases, the fastest shutter speed you’ll get is 1/8000th of a second. But it’s fair to say that’s pretty fast.
DSLRs that offer a Live View mode also use an electronic shutter. The mirror is locked up, and the image falls constantly on the sensor. The mechanical shutter usually plays a role in the final exposure.
Mirrorless cameras can also offer an electronic shutter. Now, this isn’t a shutter as such. It describes the process of turning on the individual pixels for the exposure required. This has the advantage of allowing faster shutter speeds and faster drive speeds.
At the turn of 2023/2024, Sony caused a bit of a stir by announcing that their Alpha 9 Mark III would feature a “global” shutter—a first for a full-frame camera. Simply put, a global shutter exposes every pixel at the same time.
Conventional electronic shutters expose a band of pixels at a time. This is because the data needs to be processed. Of course, the more data there is, the more processing power you need. Sony has produced a processor that can handle this high demand. And the result is an astonishing 120 fps drive speed.
Another advantage of a global shutter is that it all but eliminates the rolling shutter effect. And it offers absurdly fast flash sync speeds as well. And in the Sony, you get a maximum shutter speed of 1/80,000 s. For comparison, that’s about twice as fast as a lightning flash!
This is probably at the heart of why the DSLR is no longer the gold standard in photography. A DSLR simply cannot compete with a camera that can shoot 120 fps with focus tracking turned on.
Mirrorless vs DSLR—Autofocus
One of the main advantages that mirrorless cameras have over DSLRs is the autofocus. Autofocus systems have come a long way over the years. Modern systems can now detect eyes, distinguish between humans and animals, and track them as they move.
Mirrorless cameras have a distinct advantage in this. A DSLR AF system typically uses a semi-silvered mirror. This allows some light to pass to the focus screen and some to pass through to the AF sensor. This is a decent solution, but it limits the coverage of the AF to a degree.
A mirrorless camera has no need for a mirror. This means the AF functions happen on the sensor itself. The AF coverage can, therefore, be across the whole sensor. And it has access to all the light passing through the lens.
It also means that you’re more likely to find phase detection or hybrid AF systems on a mirrorless camera. This increases the speed and accuracy of the process.
Mirrorless vs DSLR—Sensors
Once a clear dividing line between the two types of cameras, mirrorless cameras now have sensors at least as good as their DSLR counterparts. For example, the top-of-the-range Canons (the EOS-1D X Mark III and the EOS R3) share the same DIGIC X processor. But the mirrorless R3 has a bigger and better sensor than the DSLR EOS-1D X.
The R3 is backlit with Dual Pixel AF capability. It outguns the DSLR in AF zones, speed, and control. Eye-control focus means that the camera focuses where you look.
Mirrorless vs DSLR—Build Quality
Again, it used to be the case that if you wanted pro-level build quality and weather sealing, you had to get a DSLR. But now, you will find that mirrorless cameras match DSLR specs at every level.
And if you find a DSLR too big and bulky, a mirrorless can win you over. Using the Canon examples above, the R3 body comes in nearly a full pound (450 g) lighter than the DSLR. And if you want to choose a mirrorless camera without EVF, then the difference will be even greater.
Mirrorless vs DSLR—What Is the Future of Photography?
The smart money is on mirrorless. And by smart money, we mean manufacturers’ R&D investments. At best, DSLR production is stagnant. But more often it’s a tale of discontinued models. All the innovations come in the mirrorless world, and it’s easy to see how the format will continue to outstrip what we thought was possible before.
Expect to see the major manufacturers consolidating their mirrorless ranges. And pushing their capabilities with ever-more eye-watering functionality. Eye-control focus, global shutters, pre-release image capture, and 6K video are all likely to become more commonplace.
Mirrorless vs DSLR Cameras—Conclusion
I just found out that my friend Stuart (the one mentioned at the beginning of the article who scoffed at mirrorless cameras) just bought a professional Canon mirrorless camera. This shows just which way the future of photography is heading when it comes to DSLR vs mirrorless.
The arguments really do stack up more and more on the mirrorless side. If you’re looking for a cheap first “serious” camera, then there’s a lot to be said for finding a good used DSLR. Especially if it comes with lenses to play with.
If you’re building a system from scratch, then the clear winner now is the mirrorless. Whether you’re a casual user, serious enthusiast, or pro, the future is mirrorless.