You might think that the DSLR vs mirrorless debate, and that mirrorless cameras are clearly the future. It's true that the whole market is moving towards mirrorless, but that does not mean the DSLR is officially dead. Are mirrorless cameras inherently better in every way? No!
The fact is, DSLRs and mirrorless cameras both have advantages. Both take brilliant pictures (often with the same sensors) and offer similar levels of flexibility. There will be people for whom mirrorless is the only sensible choice, and others for whom the DSLR design still feels the best. This will often come down to personal preference, not just technical differences.
Mirrorless vs DSLR: the arguments for and against
Mirrorless cameras have some well-publicised advantages. The bodies are slimmer and lighter than those of DSLRs. There's no noisy mirror mechanism when taking pictures and many mirrorless cameras have completely silent modes. Without the mirror, they are mechanically simpler.
However, DSLR-aficionados may argue that the bigger body is the key point, as a DSLR may be more practical and comfortable to grip for long periods, especially with heavy lenses attached.
And the removal of the mirror mechanism in a mirrorless camera means that they have to use power-hungry electronic viewfinders – and only the best electronic viewfinders can approach the real-time immediacy of an optical viewfinder. The amazing 9.44-million-dot EVF in the Sony A1 shows that soon you might not be able to see the difference, but that quality comes at a cost – both purchase cost and the effect on battery life.
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It's tempting to imagine that DSLRs have become locked in the technological dark ages by virtue of their design, but that's not true. Many modern DSLRs use the same on-sensor phase detection autofocus technology as the latest mirrorless cameras, so that they are just as effective when composing images on the rear screen. The Canon EOS-1D X Mark III or the Nikon D780, are two DSLR cameras that make use of mirrorless tech to deliver live view autofocus as good as any mirrorless camera's, but still with the handling and optical viewfinder of a DSLR. Meanwhile, the enthusiast-orientated Canon EOS 90D uses Canon's Dual Pixel CMOS AF and a vari-angle screen to blur the boundaries between mirrorless and DSLR camera features.
Nevertheless, the DSLR market is undeniably in decline. It's clear that Nikon's DX format DSLR range is in the doldrums, as there hasn't been a new model since the 2017 Nikon D7500, and while Pentax continues to champion the DSLR camera design, its new Pentax K-3 Mark III DSLR is an obstinately old-school DSLR which might appeal to DSLR diehards but shows just how far mirrorless cameras have come in the meantime.
• Read more: Canon EOS 90D vs EOS 80D vs EOS 7D Mark II
The fact is, camera makers are now putting all their research and development effort into mirrorless cameras. The Canon EOS R5 set new standards for focusing and 8K video capture. At the other end of the scale, Nikon and Panasonic have done a good job of producing more affordable full-frame mirrorless options, with the Nikon Z5 and the Panasonic Lumix S5. Sony, meanwhile, continues to be a formidable contender in both stills and video, with the long-awaited Sony A7S III proving to be yet another low-light monster and the remarkable Sony A1 trumping just about every other full frame camera for tech – though at a price!
So let's go through the key differences between mirrorless vs DSLR cameras in detail...
1. The mirror
DSLRs and mirrorless cameras both show the scene through the camera lens itself as you compose the picture, but the way they display it is completely different.
The SLR design was invented long before digital sensors, when the only way to show the view through the camera lens was to use a mirror in the body to reflect an image of the scene up into an optical viewfinder. When you take a picture, the mirror flips up so that the image can then pass to the back of the camera where the film (or sensor, today) is exposed to the image.
Mirrorless cameras take a different approach. They use the ‘live view’ captured by the camera sensor itself to create an electronic image that can be displayed either on the rear screen or in an electronic viewfinder. There is no mirror mechanism to flip up and out of the way.
But what sounds like a win-win situation is a little more complicated than that. First, many people prefer the optical viewfinder of a DSLR. Second, mirrorless camera makers have had to develop new on-sensor phase-detection autofocus technologies to compete with DSLRs. Third, mirrorless cameras still can’t compete with DSLRs for battery life and even – in the opinion of many users – simple handling and ergonomics.
When mirrorless cameras first became available, the way in which they autofocused was essentially in the same way as a compact camera, a system known as contrast-detect AF. This shifts the lens focus to and fro until the image seen by the sensor looks sharpest.
This is precise but also quite inefficient and slow. Compact cameras have much smaller lenses with lighter internal elements, and these can move efficiently when focusing. Mirrorless cameras have larger sensors and hence larger and heavier lens elements, so this trial-and-error focusing method is a poor alternative.
DSLRs focus using a different method called phase-detection AF. This is typically much faster than contrast-detect AF because it compares two versions of your subject from two different angles and can quickly determine which way to refocus the lens and by how much. For a long time, this gave DSLRs a serious focusing speed advantage over mirrorless cameras.
Mirrorless cameras can’t use a separate phase-detection sensor because it would obstruct the light reaching the sensor. Soon, though, mirrorless camera makers found the answer – they managed to integrate phase-detection autofocus into the camera sensor itself. The latest hybrid mirrorless autofocus systems use phase-detection AF points for speed and contrast AF for precision, and challenge DSLRs for speed. What's more, where DSLR AF sensors can only cover the central half (roughly) of the image frame, mirrorless AF systems can go right to the edges.
An early advantage for DSLRs is gone, and mirrorless autofocus system are just as fast, but extend over a much wider area of the scene.
DSLRs haven't just lost their autofocus advantage, they're stuck with an additional complication. They need one autofocus system for the optical viewfinder and another for LCD live view display. When you swap from the viewfinder to live view, you also have to swap your thinking about the autofocus modes.
Mirrorless cameras have the big advantage that the view, and the autofocus system, is exactly the same in the viewfinder and on the rear screen.
Older DSLRs like the Nikon D850 use phase-detection autofocus for viewfinder shooting but slower contrast AF for live view mode, but even though the newer Nikon D780 DSLR uses 'mirrorless' autofocus technology for more efficient live view shooting, it still has two different systems. It's the same for Canon DSLRs, like the EOS 5D Mark IV, which use the company's Dual Pixel CMOS AF system on the main sensor – you're still stuck with one autofocus system for viewfinder shooting and another for live view.
Focusing is only one aspect of the DSLR vs mirrorless design, and what makes a camera suitable for a particular type of photography. Many sports photographers continue to use DSLRs rather than mirrorless cameras, partly because of AF performance but also because of their battery life, size and 'grippability' with bigger lenses.
Even so, mirrorless cameras can now be successfully used for this kind of photography where they would have previously been completely unsuitable. In fact, if you look at the capabilities of the hybrid on-sensor autofocus system in the latest Sony A7 IV, even DSLR diehards would have to concede that the separate phase-detect AF systems in DSLRs are dinosaurs by comparison.
The design of mirrorless cameras means they need to use electronic viewfinders. These have improved hugely in a very short space of time, but they can still polarise opinion. In the early days their resolution was too low to display a scene with anything like the clarity and detail of an optical viewfinder, and they had so much ‘lag’ when you moved the camera quickly that it was difficult to follow moving subjects.
Early EVFs might have been pretty poor, but the latest and best electronic viewfinders available today have such high resolution that you can hardly see the ‘dots’ and they have a clarity that genuinely approaches optical viewfinders. Panasonic's Lumix S cameras brought the highest EVF resolution to date at over 5 million dots, and that's only just been beaten by the 9.44 million dots of the Sony A1.
Viewfinder lag is less of an issue than it used to be thanks to faster refresh rates, and the most recent area of focus for manufacturers has been in the blackout effect you would typically see when shooting continuous bursts of images. Sony managed to eliminate this on its A9 model, and Panasonic claims the same for its Lumix G9 .
On top of all this, electronic viewfinders let you view the image with any changes to exposure, white balance, colour settings and so on applied instantly, something optical viewfinder cannot do.
Electronic viewfinders can show a more clearly visible view of a scene in low light, and have zoom functions for precise manual focusing – two highly underrated benefits of electronic viewfinders. Because of their auto-gain light amplification effect, electronic viewfinders let you compose and shoot images in near darkness, and have made small-aperture telephotos like the Canon RF 600mm f/11 and RF 800mm f/11 perfectly practical to use.
It's also worth pointing out that if you are a fan of vintage manual lenses which need to be used in stopped-down mode, a DSLR viewfinder will be way too dark but a mirrorless EVF will be fine.
But before we assume an EVF is best at everything, there are a couple more things to consider
What's good about optical viewfinders
Many photographers prefer the ‘naked eye’ view of an optical viewfinder over a digital rendition. It’s a mistake to assume electronic viewfinders are inherently more ‘accurate’ because the display depends not only on the camera settings (which you may change later if you shoot RAW images) but on the quality, contrast ratio and calibration of the viewfinder panel itself. These often display more contrast than the captured image, for example, and can mislead you into correcting exposure settings that don’t need correcting.
Optical viewfinders have another key advantage that’s particularly relevant for sports and action photographers. There is unavoidable screen blackout in the camera’s burst shooting mode as the mirror flips up and down between exposures, but this is rarely an issue – the key point is that there is no lag, and it’s much easier to follow a fast-moving subject with a high-speed DSLR like the Nikon D500, for example, than it is with the average mirrorless camera.
The gap is closing, however, as EVF resolution, data readout and processing speed improvements bring electronic viewfinders every closer to the performance of the optical kind.
4. Battery life
Even very basic DSLRs will happily offer 600 shots per charge of the battery, but many stretch into four figures. The entry-level Nikon D3500 DSLR, for example, can capture up to 1,550 images on a single charge. The very best pro DSLRs can rattle off almost 4000 frames per charge, although this is admittedly with considerably larger batteries. With the new Nikon D6 pro DSLR, Nikon claims a stunning battery life of 3,580 shots – and twice that if the camera is used for high-speed continuous shooting.
Mirrorless cameras, however, fare far less impressively here, with around 350-400 frames per charge being the norm while some are a whole lot less. The Sony A7R III ushered in an extended 650-shot battery life almost double that of its predecessors, and the Sony A7R IV even improves on that slightly, so that’s a significant step forwards, but the Canon EOS RP can only manage 250 shots. Battery life is an issue for mirrorless cameras, but why is this?
Mirrorless cameras are inherently more dependent on battery power than DSLRs. Either the LCD display or the electronic viewfinder is on all the time. Furthermore, the fact that most manufacturers try to make mirrorless models as small as possible means that their batteries are also small, which also presents a limit on their capacity.
Many mirrorless cameras also have image stabilisation built into their bodies, such as the Fujifilm X-T4, which further reduces battery life (although you’ll also notice battery life to be less impressive when using lens-based image stabilisation on either DSLR or mirrorless cameras).
Of course, you can buy spare batteries for cameras in both camps, so whether this is as great an issue or not is debatable. One advantage of mirrorless cameras, however, is that many now offer charging through their USB ports, like the Sony A6400, which is very convenient when travelling, though this is starting to appear on DSLRs like the Nikon D780 too.
The most often claimed advantage of mirrorless systems is that they are much smaller than DSLRs. This is the main sell of mirrorless systems: the same size of sensor and image quality as offered by a DSLR without the bulk.
But there are often trade-offs in making a mirrorless camera body so compact, such as battery life, the way a camera handles with larger lenses, and how much space there is for external dials and buttons.
Some mirrorless cameras fashioned like smaller versions of a DSLR while others have a smaller rectangular ‘rangefinder’ shape. These are often designed for novice camera users or smartphone upgraders more used to touch control than physical knobs and dials, so a simplified exterior won’t bother them. The Olympus PEN E-PL9 is typical of small mirrorless cameras designed for this new type of user.
Small bodies also means small controls, and users with larger hands may not find smaller mirrorless bodies easy to use. This extends to touchscreens too, with virtual buttons and controls often too small for then to be keyed comfortably, so although the Nikon D850 DSLR seems huge in comparison to today's full frame mirrorless camera, many of its pro users will prefer its size because it makes it much easier to see and change camera settings – and because it balances better with big lenses, which is what we cover in the next section.
DSLRs still have an advantage for lens choice, simply because they've been around and supported for decades. Anyone that opts for a Canon EOS DSLR today has 30 years’ worth of native optics to choose from, and many more when you factor in compatible third-party options. Nikon and Pentax are in a similar position with their DSLR ranges.
However, there are signs that DSLR makers are scaling back their DSLR lens production, and the development of new DSLR lenses has certainly slowed. Canon and Nikon now put almost all of their lens development effort into mirrorless lenses.
It hasn’t taken Sony long to assemble an impressive range of lenses for its full-frame FE mount mirrorless cameras (see our list of the best Sony lenses), and Panasonic has been smart enough enter into an L-Mount Alliance with Sigma and Leica to ensure that it's already supported with a large and growing lens range. See our guide to the best L-mount lenses for more.
Nikon and Canon have been especially clever with their new full frame mirrorless cameras. The Nikon mirrorless Z 6 and Z 7 have a steadily increasing number of native lenses, but you can also get an FTZ mount adaptor for using any of Nikon’s current DSLR lenses without restriction. Canon has also launched lens adapters for its EOS R full-frame mirrorless cameras, opening up its entire range of EF DSLR lenses to these cameras.
Fujifilm and Olympus have also had time to develop their own native lens systems, to the degree that none of the mirrorless camera brands is now at any real disadvantage regarding lens choice (see our list of the best Fujifilm lenses, for example).
But are mirrorless lenses really smaller?
This is where the mirrorless bubble is in most danger of bursting. Mirrorless camera makers can indeed demonstrate that their camera bodies are a lot smaller than their DSLR counterparts, but the same can’t be said for their lenses.
It’s an inescapable fact that it’s the sensor size that largely determines the size of the lenses that go with it. Some mirrorless makers have produced small or retracting lenses that do offer a size saving, but these come with other compromises, and when lens makers produce mirrorless lenses to match the specifications and performance of DSLR lenses, they end up pretty much the same size.
In fact, because mirrorless camera makers are keen to exploit the potential of new, larger mirrorless lens mounts, they are coming up with lenses that are actually bigger and heavier than their old DSLR counterparts.
This not only undermines the ‘mirrorless is smaller’ argument, it produces handling issues with certain camera-lens combinations. Sony’s A7-series camera bodies are remarkably small, but many of its lenses – especially its top-quality G Master lenses – are unexpectedly big. You might find yourself buying a battery grip for your mirrorless camera just to make it handle better with your favourite lenses.
This is where mirrorless cameras have a considerable advantage, and for two main reasons. First, their design makes them much better suited to the constant ‘live view’ required for video capture. Second, this is where camera makers are concentrating their video capture technologies and where you’re going to get the best video features and performance.
DSLRs can shoot video too
Actually, DSLRs are where mainstream video with regular interchangeable lens cameras began. The Nikon D90 brought HD video to the consumer market, and the Canon EOS 5D II brought DSLRs into the professional videography and film-making arena.
For today’s DSLRs, video capture is a standard feature, and the Nikon D5, D850 and Canon EOS 5D IV offer 4K video capture easily good enough for all but the most demanding professional use, while the Nikon D780 is as effective for video as any mirrorless camera.
Even so, when it comes to 6K and 8K capture, raw or 10-bit video, high frame rates and more, all the effort and development work is going into mirrorless cameras.
DSLRs can still shoot video that’s fine for commercial photographers working for clients who’ve started asking for this alongside still images. But the best mirrorless cameras have stretched out a big gap in features and performance to the extent where they're competing with full-on cinema cameras and broadcast-quality camcorders.
Sony has led the way with high-quality ‘oversampled’ 4K video in its full-frame mirrorless A7-series cameras like the A7 III, and Fujifilm and Panasonic now have cameras capable of capturing 4K video at 60/50fps for smooth 2x slow motion effects in the Fujifilm X-T4 and Panasonic Lumix GH5 Mark II and GH5S. The Panasonic Lumix S1H has already received accreditation from Netflix for original content creation.
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The Canon EOS R5 also got much attention for its 8K 30p video capabilities, though this has proven to be something of a paper tiger upon the revelation that it causes the camera to overheat if it runs for longer than about 20 minutes. This looks like a glitch not an obstacle, as Sony has joined in with the 8K Sony A1, which can run for a lot longer.
If you only need video occasionally a DSLR will be fine, but if you need to shoot it as an important (or the most important) part of your work, then mirrorless is the way to go. It’s not just the cameras – mirrorless lenses increasingly feature high-tech focus actuators and silent stepping motor autofocus technology for smooth and silent focus transitions when filming; the majority of DSLR lenses were designed at a time when this wasn’t even imagined.
DSLR vs mirrorless: the final word
Despite the rush towards mirrorless camera technology, the DSLR vs mirrorless debate is not completely one-sided. Here's a summary of the pros and cons of each camera type.
When to choose a DSLR
DSLRs have disadvantages, but they have advantages too. They’re bigger, fatter, chunkier and more ‘grippable’. They handle better with bigger lenses (and lenses are getting bigger, year by year) and they have more space for external controls, so you spend less time navigating digital interfaces, tapping at touchscreens (try that when they’re damp with mist or rain or you’re wearing gloves) and their batteries last all day instead of just the morning.
They also have optical viewfinders. Mirrorless users might not care, but DSLR fans would never swap the ‘naked eye’ viewfinder image of a DSLR for a digital simulation, no matter how good.
There’s another thing. If you’re on a tight budget you’ll have to work hard to find a mirrorless camera with a viewfinder for the same price as a DSLR – and all DSLRs have viewfinders. Actually, we’ll go further. You will struggle to get a mirrorless APS-C camera with a viewfinder for the same prices as a Nikon D3500 or a Canon EOS 2000D. Except for the Sony A6000, but that’s a five-year-old camera. DSLRs are amongst the best cameras for beginners.
DSLRs are still a great choice if you like your cameras big, chunky and physical, which is why they are still among the best cameras for professionals. They can do video too, but if that’s your main interest then probably you should be looking at a mirrorless camera instead.
When to choose mirrorless
Mirrorless camera bodies are smaller and, if you choose carefully, you can get smaller lenses to go with them – though this only really holds true with the Micro Four Thirds format, as APS-C and full frame mirrorless cameras come with lenses as large as their DSLR counterparts.
If you’re an Instagramer, influencer, blogger or blogger, a mirrorless camera like the Olympus PEN-EPL9 or Canon EOS M50 is perfect. They’re small, light and adaptable and have tilting/vari-angle screens that let you shoot from all sorts of angles. They’re great for both video and stills and can easily fit in an everyday bag.
If you’re a pro or semi-pro videographer, mirrorless is the way to go here, too. This is where all the video development in cameras, lenses, hardware and accessories is happening with cameras like the Nikon Z6 II and Sony A7 III. The Panasonic Lumix S1H is a video-centric mirrorless model that's making inroads into the pro cinema market, and the Fujifilm X-T4 is a mirrorless camera with video specs that are currently out on their own in this price range.
But if you’re a regular stills photographer who occasionally dabbles in video, the choice is tougher and you have to decide for yourself which you prefer. The market is heading towards mirrorless, but DSLRs are still popular, and there are plenty of people out there who would like this resilient and adaptable old camera design to keep on going for ever.
DSLRs aren’t done. Mirrorless cameras might be the future, but the future isn’t here yet, and for now the DSLR design still does a few things brilliantly where mirrorless cameras are still playing catch-up.
There is one final paradox. You might say that the DSLR design is retro, but in fact if you want a camera that looks and feels the way cameras used to, then mirrorless is the way to go! See our guide to the best retro cameras to see why.