Mirrorless vs DSLR: introduction
How do you make the right choice in the great mirrorless vs DSLR camera debate? Things have certainly changed in the decade since mirrorless cameras first arrived on the market, but our in-depth guide is here to give you all the answers.
These days, mirrorless cameras are now the default style for the world's biggest camera brands – even the doyens of DSLRs, like Canon and Nikon. Back in the early days of the format, the decision was pretty simple – if you were a pro, you tended to pick up a DSLR. Hobbyists and amateurs, who were more bothered by weight and portability, would instead lean towards their mirrorless counterparts.
But now the roles are somewhat reversed. The latest and greatest technology is now found in mirrorless cameras. And if you’re an entry-level user, you might be more likely to go for a cheaper DSLR, given they remain the most affordable way to get a camera with a built-in viewfinder.
For those in between beginners and pros, there's now more choice than ever before, which can make choosing the right camera tech for you somewhat tricky. But fear not, that’s where we come in.
Let’s start with the basics and look at the key differences between the two types of cameras. The key is in the names. DSLR stands for Digital Single Lens Reflex, which works by the light hitting a mirror angled at 45 degrees. That light goes straight up into an optical viewfinder which allows you to see precisely what the lens is looking at. This is a true optical path, with no digital processing in the middle.
When you’re ready to take a photograph, that mirror moves out of the way – to reveal the image sensor – and if you’ve used one in the past, you’ll be familiar with the satisfying (but fairly loud) noise it makes as it does so.
By contrast, mirrorless cameras – you’ve guessed it – don’t have a mirror. With these cameras, the light passes through the lens and straight onto the sensor to be processed. It’s then displayed either on the monitor on the back of the camera, or in the electronic viewfinder (EVF), which is in essence a very small monitor. This time, when you take a picture, the camera is simply recording what is on the sensor at that moment in time.
DSLRs use the same technology as their film counterparts, which have been around for decades. They’re very familiar for anybody who has been serious about photography in recent years. Legacy companies such as Canon, Nikon and Pentax have been making them for all those years and so have a lot of experience to draw from.
These days, relatively few new DSLRs are introduced to the market, but there’s still plenty you can buy. They tend to have great handling, offer fantastic image quality and one advantage that doesn’t look set to go away for a while yet – extremely impressive battery life.
By taking away the mirror, mirrorless cameras give you several advantages (and very few disadvantages). The key one is that, since they don’t need that big clunky mirror setup, they can be smaller and lighter than their equivalent DSLR counterparts.
Some of the tasks of the camera, like autofocusing, can take place on the sensor itself, leading to super-quick focusing speeds. Speaking of speed – with no mirror to move out of the way, frame rates aren’t limited so much by physicality. Mirrorless cameras routinely offer at least 10fps, with some high-end models delivering 20fps or 30fps at full resolution, with continuous autofocus between each shot.
In the beginning, mirrorless cameras tended to use smaller sensors than DSLRs. But now, the most popular sensor size in these models is full-frame, with Sony, Nikon, Canon and Panasonic all producing this type of camera. APS-C is also a common sensor size, for both mirrorless and DSLR. All of this means that there’s no generally discernible difference between outright image quality in DSLRs and mirrorless cameras, no matter which you choose to go with.
The electronic viewfinders found on early mirrorless cameras weren’t particularly great, being low in resolution and slow. But over the years the technology has advanced so much that many photographers now prefer the super high-resolution viewfinders on the current crop of high-end mirrorless cameras. They show a truer reflection of what your final image will look like, as well as allowing you to see a preview of your image after you’ve shot it.
All of this makes it sound like mirrorless is the obvious winner – and while the fact that barely any new DSLRs have been announced in the past 12 months might seem to back that up, there are still some advantages of the older technology.
We’ll discuss the main differences in the coming pages to help you come to a firm conclusion.
1. Size and weight
- DSLR: Traditionally, these were the bigger of the two. This isn't necessarily a negative, as it can help when shooting with big telephoto lenses (and big hands). These days though, mirrorless cameras can be just as large as DSLRs.
- Mirrorless: On the whole, mirrorless cameras are generally smaller and lighter than the average DSLR, making them ideal for travelling light and keeping the overall weight down. You'll find some pro mirrorless cameras break this 'rule' though.
When mirrorless cameras first entered the market, one of their big selling points was their small size. The first cameras of this kind to get really popular were Micro Four Thirds models, which traded on the idea that the overall system was much smaller and lighter than their DSLR equivalents.
As larger sensor sizes started to become popular, it no longer became a simple statement of fact that mirrorless meant 'smaller'. When you use an APS-C or a full-frame sensor, you might be able to get a small(ish) body, but the compatible lenses will likely be big and heavy. Some manufacturers have attempted to answer the problem with retractable or 'power-zoom' kit lenses, but as soon as you need to swap to a different type of lens, the problem appears again.
If size and weight is your main concern, the Panasonic G series and Olympus cameras have the advantage. They use the Four Thirds sensor format inside their Micro Four Thirds models, which are smaller than APS-C and full-frame sensors. There's an argument that image quality can't match larger sensors – especially in some shooting scenarios such as low light – but the smaller sensor helps to deliver a much more compact system all round. And it's great for those who need high levels of zoom in a small package.
Some higher-end mirrorless cameras are actually very large, with some manufacturers responding to feedback from pros who say they'd prefer larger grips for better ergonomics. That even includes cameras like the Olympus OM-D E-M1X, which has a small sensor and a large body that incorporates two grips.
Panasonic's introduction of its L Mount full-frame cameras, such as the Panasonic Lumix S1, are also very large, and are even bigger than some existing DSLRs.
Conversely, entry-level DSLRs are shrinking to compete with the smaller footprint of similarly priced mirrorless cameras. Nikon's D3500 and Canon's EOS Rebel T7 / 2000D are charmingly small and light, making them less of a burden to carry around.
- DSLR: There's a huge range of lenses available for DSLRs, as both Canon and Nikon have an optic to suit every job. Pentax also has a lot of bases covered, while options from third-party manufacturers also make for a comprehensive set of compatible options.
- Mirrorless: While there are slightly fewer options for mirrorless cameras, most bases are now covered, particular for older systems such as Sony, Fujifilm and Micro Four Thirds. Newer systems such as Canon's R and M mount, Nikon's Z mount, Fujifilm's GFX series have fewer, but the range is expanding all the time. If you need something niche, you can often use DSLR lenses with a mirrorless camera via an adapter.
Technically speaking, if you want the widest possible choice of lenses, a Canon or Nikon DSLR will be your best bet. Each of these options has a huge range of lenses at a variety of price points, with third-party manufacturers such as Sigma and Tamron also providing options.
DSLRs have the age advantage, with the lens format having been around for decades. But the options available for mirrorless cameras have caught up rapidly, and now there’s a diverse range of lenses to suit almost every need, with more new lenses being added as time goes on. It's really only those with very niche needs who are missing out by choosing mirrorless.
The longest established mirrorless system – although now falling in popularity – is Micro Four Thirds, used by Olympus and (some) Panasonic cameras. As such, this system offers the most all-encompassing range at the moment.
Fujifilm’s X-series is also pretty comprehensive, having been around for a similar length of time. Its medium-format GFX series has fewer options, but is gaining ground as the years go by. Both offer a good set of zoom and prime lenses, and while there are still a few gaps here and there, they tend to be niche optics that the average consumer won’t be too bothered about being without.
Sony’s APS-C and full-frame mirrorless cameras have been around for quite some time now. They share the same mount, so while there are lenses that are specifically designed for either APS-C or Full-Frame, being able to swap between the two is beneficial for those upgrading. There are some high-end optics which are matched perfectly to models such as the Sony Alpha A7 III, including specialist optics like the Sony FE 600mm f/4 GM OSS telephoto prime lens.
Frustratingly, Canon has two lines of mirrorless cameras, APS-C and full-frame, which don’t use the same mount. Both are also different from the mounts used by its DSLRs, too. If you are an existing Canon DSLR owner, the good news is that you can use mount adapters on its mirrorless systems, giving you the option to only replace lenses as and when its necessary, rather than all in one go.
Right now, there’s a healthy range of lenses for EF-M and RF mounts, but there are still some significant gaps to be filled, especially with the RF mount being so new. But with the recent introduction of the Canon EOS R5 and Canon EOS R6, we expect a lot more lenses to be announced in the coming months and years.
Nikon, meanwhile, uses the same mount across both its APS-C and full-frame mirrorless systems. The Z-mount is different from the F-mount used by Nikon DSLRs, but if you already have some lenses, you can use an adapter to bring those across. It’s a pretty seamless transition and helps to fill in any gaps in the line-up while we’re waiting for Nikon to expand its mirrorless lens range. At the time of the system's launch, there were only a handful of Z-mount lenses, but there’s a good degree of choice now.
Another fairly recent introduction is the L-mount alliance, which is a joint venture between Panasonic, Sigma and Leica. These three companies are developing products that can be used in conjunction with each other, giving buyers the advantage of triple the range – and triple the development power. There’s already a good range of lenses available for L Mount, with more appearing regularly.
- DSLR: Some photographers, particularly sports shooters, still prefer an 'optical' view for its clarity, natural look and lag-free viewing. These are standard on DSLRs.
- Mirrorless: Early electronic viewfinders were low in quality, but recently the tech has improved so much that it's actually a preferable way of shooting for many. You'll get a real-time view of the scene you're shooting, along with vital information displayed easily.
All DSLRs, even the cheapest, come with an optical viewfinder, because it's an integral part of the DSLR design. Although it's relatively rare in current line-ups, some entry-level mirrorless cameras, on the other hand, don't have viewfinders at all. This means your only option is to compose photos via the rear LCD, which is a boon for portability, but doesn't always work so well in bright sunlight.
Mirrorless cameras use electronic rather than optical viewfinders. That means they display the image directly from the sensor readout and not via an optical mirror/pentaprism system.
Electronic viewfinders are advancing at a fast pace, and the latest rarely show any graininess that was an issue in earlier generations, while the visible lag that was once common has all but been eradicated.
The advantage of electronic viewfinders is that they can display a lot more information than an optical viewfinder, including live image histograms, for example. They can also simulate the digital image the camera will capture, so you don't get any horrible surprises when you review your image, as it's exactly what you're seeing.
This simulation is not always perfect, however, and many photographers prefer to see the world with their own eyes as they compose the image, then check the digital version on the LCD once it's been captured. Optical viewfinders are also easier to use in low light.
This will come down to personal preference; get one of the latest high-end mirrorless cameras with a large magnification, large resolution electronic viewfinder, and you'll be hard pressed to find fault with it. The Sony A7S III is an example of a simply stunning electronic viewfinder, offering superb clarity. And this is increasingly becoming standard on the latest mirrorless cameras.
- DSLR: Used to have a clear autofocus advantage, but no longer. Some DSLR systems are better for moving subjects, but it's not straightforward.
- Mirrorless: While entry-level models may struggle, many mirrorless cameras now have hybrid contrast- and phase-detect AF systems, which fare much better. Several systems are as reliable as those on DSLRs, if not more so.
Professionals who wanted the very fastest autofocusing used to head straight for DSLRs. But these days, with fantastic advances made in mirrorless technology, it’s very often the newer type of camera that has the advantage – especially if you go for premium mirrorless options.
High-end DSLRs haven’t been updated in some time, but models such as the Nikon D850 and Canon EOS-1D X Mark III still offer sophisticated systems. They use fast and efficient ‘phase-detection’ autofocus modules which are mounted below the mirror in the camera’s bodies.
However, DSLR systems are limited by the fact that their autofocus only works while the mirror is down. This means that fast frame rates are difficult to achieve, since this needs to be moved out of the way each time. You could switch to using Live View, but that means the regular AF module is no longer in the light path and a slower contrast-detect AF system is used.
Some slightly newer DSLR models, such as the Canon EOS Rebel SL3 / EOS 250D and Canon EOS 6D Mark II have included Dual Pixel CMOS A, which uses phase-detection pixels built into the sensor. This gives faster autofocus in Live View, and while it helps to close the gap on mirrorless cameras, we’re now seeing such incredible systems from several manufacturers that mirrorless definitely now has the edge.
Since there’s no mirror, these types of cameras use sensor-based autofocus all the time. Many are contrast-based AF, but they tend to be faster than the equivalent AF modes on DSLRs. More mirrorless models are now using advanced hybrid AF systems, which combine contrast-detect with phase-detect AF from the sensor to deliver exceptional performance.
They impress not only with their speed, but also accuracy when it comes to tracking a moving subject. Both the Canon EOS R5 and the Canon EOS R6 are two recent introductions that offer almost unerring accuracy when tracking a subject, while Sony models such as the Sony A7 III also put in an excellent performance, using “Real-Time AF” tracking to closely follow your subject with just a simple half-press of the shutter button. It’s almost too easy. Super high-end models such as the Sony A9 II and the very recently announced Sony A1 are fantastic options for sports and action photographers who simply can’t afford to miss a shot.
Another advantage that many mirrorless cameras offer is eye- and face- detection which makes photographing people (and animals) even more accurate. All of the major mirrorless brands offer Face/Eye detection, helping you to get sharp shots almost without fail – it’s something you might need to activate from the main menu rather than it being used by default, though.
5. Continuous shooting
- DSLR: The best DSLRs can no longer match the speeds of the best mirrorless cameras
- Mirrorless: The mirrorless design makes it easier to add high-speed shooting and even cheaper models have relatively fast burst speeds
You need a fast continuous shooting mode to capture action shots, and mirrorless cameras are streaking ahead here. This is partly because the mirrorless system has fewer moving parts, but also because many models are now pushing ahead into 4K or even 8K video – this demands serious processing power, which helps with continuous shooting too.
To put this in perspective, Canon's top professional DSLR, the Canon EOS-1D X Mark III, can shoot at 16 frames per second when using the viewfinder, but mirrorless cameras like the Panasonic Lumix G9 and Sony Alpha A9 II can both shoot at a staggering 20fps. The new Sony A1, meanwhile, has raised the bar again with 30fps continuous shooting with autofocus, an impressive achievement.
You have to be a little careful, though, when looking at the specs. Some mirrorless cameras will boast even higher frame rates than this (in some cases, up to 60fps), but will have to use an electronic shutter to achieve this and focus will be fixed from the first shot. This isn't great if you're planning to track a moving subject, or shoot under some types of artificial light, where banding can occur without the use of a mechanical shutter.
You've also got to be realistic about what kind of burst shooting speeds you are going to need; shooting at 60fps means you'll fill up a memory card pretty quickly, and you'll have to spend a lot of time trudging through a multitude of images to find that 'one' shot. That said, with even entry-level mirrorless cameras offering faster burst shooting speeds than most DSLRs, mirrorless cameras certainly have the edge if this is your priority.
- DSLR: Once massively popular with pros, but have long been overtaken by mirrorless rivals.
- Mirrorless: 4K video is now standard on all but the cheapest mirrorless cameras, with some now starting to offer 6K/8K.
DSLRs were well ahead of mirrorless cameras when it came to offering professional HD and Full HD video capture. Their vast range of lenses and other accessories made them a hit with pro video makers – the Canon EOS 5D Mk II, in particular, changed the game by shooting video from a full-sized sensor, for far less money than many pro cameras.
But the shift has certainly been towards mirrorless cameras favor in recent years, offering a wealth of video features that most DSLRs can't match.
4K capture is a more common feature for starters on mirrorless cameras, while DSLRs have been slow to offer this functionality. With relatively few new DSLRs appearing in recent months, there's not too many to choose from if you need this kind of video. For entry-level models that do offer it – such as the Canon EOS Rebel T8i / EOS 850D – a heavy crop is applied, which is pretty limiting in many situations.
There's also the efficient live view autofocus and processing power offered by mirrorless cameras, while the growing range of adapters and accessories out there offer video shooters a more complete system.
The Sony A7S III is currently our pick for the title of best 4K camera. It offers stunning video quality, and though it’s less well-suited for stills than some other models, for those whose main concern is movie capture it’s simply the best you can buy right now.
That said, we're also now starting to see even higher resolution options come to the market. One of the Canon EOS R5's headline features is its ability to record 8K video, albeit with some limitations. We expect this to become the norm over the coming years as the technology develops and becomes more commonplace.
Panasonic has carved out a niche for itself with the Panasonic Lumix GH5 and Panasonic Lumix GH5S, offering a hybrid stills/video camera that's loved by enthusiast photographers and professional cinematographers.
Also from Panasonic is its full-frame Panasonic Lumix S1H camera, one of its full-frame L-Mount Alliance models. We've been told that this has vastly outsold the more stills-oriented S1/S1R models due to its fantastic video credentials, giving you an idea of just how important video is to the company – and mirrorless camera fans.
- DSLR: Even entry-level models have full manual controls, and DSLRs are powerful cameras
- Mirrorless: They match DSLRs feature for feature, often going a step or two further
In the past, it was hard to split DSLRs and mirrorless cameras on their feature sets. But these days, with more money and time being thrown at the development at mirrorless cameras, the latter are now the clear winners.
Both DSLRs and mirrorless cameras offer full manual control over exposure and give you the opportunity to shoot both raw files and JPEGs. Image quality between the two is pretty much identical, aside from the newer sensors found in mirrorless bodies. In any one sector, such as entry-level cameras, enthusiast or pro models, the control layouts and capabilities are pretty similar, too. Entry-level DSLRs tend to hide away the manual controls under a layer of automation, but it's the same for mirrorless cameras.
While the feature set of high-end DSLR cameras is generally pretty impressive, it's fair to say that the average mirrorless camera now beats the average DSLR on specs. Most mirrorless cameras offer advanced IBIS (in-body image stabilization systems), advanced autofocus technologies such as tracking and eye-detection, 4K video as standard and more besides.
Processing power is at its height in mirrorless cameras – again, by virtue of them being newer. These high-end processors facilitate some of the more impressive features, including high ISOs, fast shooting speeds and 4K video at faster frame rates.
The fastest autofocusing, as well as the most comprehensive spread of points across the sensor, is now with mirrorless cameras, while super-fast frame rates of up to 30fps are only really possible thanks to the lack of a mirror.
Most mirrorless cameras offer articulating or tilting touch-sensitive screens, and although there are several DSLRs which offer the same, you'll now see the best screen technology (and menu systems) on mirrorless cameras. Optical viewfinders were often the preference, but with dramatic advances in EVF technology over the past few years, many people have now switched to electronic 'finders.
8. Image quality
- DSLR: DSLRs use APS-C or full-frame sensors.
- Mirrorless: The cameras typically use the same sensors, but there are also smaller formats for even smaller cameras. There are also some medium format mirrorless options, too.
There's nothing to choose here, either. Currently, the highest resolution can be found in a mirrorless camera, the medium format Fujifilm GFX100S, which has a 102MP sensor. Admittedly, that's not a camera many people can afford, although the cheaper Sony A7R IV mirrorless camera manages 61MP – still a good 11MP more than the closest DSLR, the Canon EOS 5DS and 5DS R.
It's not just about megapixels, though, because the main factor in image quality is sensor size. With the exception of medium format sensors, full-frame sensors are the biggest and offer the best quality in low light, while cameras with APS-C sensors are competitive on image quality and much cheaper – you can get either of these sensor sizes in both DSLRs and mirrorless cameras.
But the compact system camera market offers smaller formats too. The Micro Four Thirds format used by Panasonic G series and Olympus is smaller than APS-C, but so are the cameras and lenses, so you need to weigh up what's most important to you – size or ultimate image quality.
Overall, then, there's no intrinsic image quality advantage in a DSLR, given that the same sensor sizes are available in mirrorless cameras, too.
9. Battery life
- DSLR: 600-800 shots is average, better models can shoot over 1,000 shots on a charge. Pro DSLRs may offer 2000+ shots per charge
- Mirrorless: Much weaker, typically around 300-400 shots per charge. Some manage around 600 or 700, although those with a higher battery life will often have either very large batteries or require two
Battery life comparisons might not be exciting, but they are important when the differences are as great as this.
The very affordable Canon EOS Rebel SL3 / EOS 250D DSLR, for example, can take 1,070 shots on a single charge, while the Fujifilm X-T4 mirrorless camera, a much more advanced model, can only shoot 500 photos before the battery expires. This pattern is repeated across the range of DSLRs and mirrorless cameras.
Why's this? DSLR batteries are sometimes larger, though not always, and you might have thought that driving the mirror up and down for each shot would consume more power, and that that LCD display would be used just as much. However, mirrorless cameras also have to power an EVF in most cases as well, and this is why they still have much shorter battery lives.
So, this is one area where DSLRs do often have a substantial practical advantage. If you're somebody that likes to shoot a lot in any given day, then you'll almost certainly need to invest in a second battery, or look for a mirrorless model that offers USB charging, so you can use a power bank while on the go. That isn't too difficult these days, though – most recent mirrorless cameras offer in-camera USB charging.
- DSLR: The cheapest DSLRs may miss out on some feature like touchscreens and 4K video
- Mirrorless: Cheap mirrorless cameras often have these features but don't have viewfinders; those that do cost more than equivalent DSLRs.
You might hope that the simpler design of a compact system camera would make them cheaper to buy, but that's not necessarily the case. If you want a fully-featured, 'proper' camera with a viewfinder for the least money, then a DSLR is still the cheapest option – but it's getting a lot closer between the two.
For example, the 24MP Nikon D3500 DSLR has a great APS-C sensor, an optical viewfinder (of course), decent manual controls and a staggering 1,550-shot battery life.
Its nearest rivals on price include models such as the Sony Alpha A6000, which packs in an almost identical 24MP APS-C sensor and features a built-in electronic viewfinder. That said, it's only that cheap because it's been superseded.
Once you get into enthusiast and pro market, however, the differences largely disappear – for any given amount of money you get broadly the same features, performance and power.
Mirrorless vs DSLR: the verdict
- DSLR: Sturdy, good value cameras that offer impressive handling and top image quality
- Mirrorless: Technically more advanced, often smaller and lighter, and definitely the way forward.
In times gone by it was harder to give a definitive answer in the mirrorless vs DSLR debate. But these days it's getting more difficult to argue the case for the DSLR. With more and more mirrorless models coming onto the market – and fewer and fewer DSLRs – it's become increasingly clear which way the future lies.
Mirrorless cameras give you the advantage in many different scenarios. They are generally lighter and smaller their DSLR equivalents – often with smaller and lighter lenses to match, too. They bring a comprehensive, modern feature set, such as superlative AF tracking performance, 4K video recording and IBIS, where DSLRs are now starting to fall behind.
That said, there's still something to be said for DSLRs – and there's still some life in the old dog yet. On the whole, because they're older and lack EVFs, they tend to be a cheaper proposition than mirrorless cameras, and you can pick up some great bargains.
The trade-off is that you might not get the latest tech, but not every photographer needs it. DSLRs also give you a more comprehensive lens range, too. Battery life for mirrorless cameras is still some way behind DSLRs and, while it is improving, nothing yet quite matches what a DSLR is capable of in that respect.
The ergonomics of both high-end DSLRs and high-end mirrorless cameras are fantastic, but it's arguable that cheaper mirrorless cameras aren't quite as pleasurable to use as cheaper DSLRs. This is, though, often down to personal choice and shooting preferences. There's now less to choose between optical and electronic viewfinders, with the latest iterations now being so good that many often prefer them.
If you're already invested in the DSLR system – or perhaps you really do have a strong craving for their shooting style – there's still a little bit of life left in them. We won't write them off completely just yet, but it seems relatively unlikely we'll be seeing many new releases from here. Nikon has already said as much, and other manufacturers like Canon are likely to follow suit.
All in all, it's safe to say that if you're coming to a 'real' camera for the first time, it makes more sense to choose mirrorless now. It's clear that every manufacturer will be pursuing advances in this area much harder than DSLRs, which will be consigned to the history books over the next decade.
Right now, there's never been more choice – but for most photographers, mirrorless makes the most sense.