(Pocket-lint) - DSLR cameras - which stands for digital single lens reflex, not to be confused with mirrorless cameras (covered in this separate feature) - have removable lenses so that different optics can be attached in order to give a different view onto the world. This potential variety allows you to start small and build-up to the more varied, sharper and desirable featured lenses as you go along.
So whether you're new to DSLRs, looking to upgrade, know plenty about cameras already, or are considering a more pro option, we've broken down our list of great DSLR cameras into sub-headed categories to make things easier to digest. This is where we round-up the best DSLR cameras available to buy today.
A quick lesson in lenses
First thing's first: cameras don't work in a one-size-fits-all way. Brands like to keep their own heritage and, as such, each manufacturer has its own lens mount.
For Canon it's EF-mount (including EF-S), for Nikon it's F-mount, for Pentax it's K-mount, and Sony has A-mount (although it has recently ceased to sell A-mount camera bodies). There are some additions and exceptions, but those are the current main four. Don't fall into the trap by buying the wrong lenses just because the brand names match up.
Second to the equation is sensor size. Entry and mid-level cameras typically have what's called an APS-C size sensor. Some pro-spec cameras have full-frame sensors that, because they're physically larger, need specific (typically pricier and more advanced) lenses that are capable of covering these larger dimensions.
There are plenty of things to consider with lenses and this all depends on the type of photography you are planning on doing. If it's all about portraits you'll want something around the 50mm or 75mm mark. If you are trying to snap that lion on the Savannah and don't want to get eaten then you'll want something with a long zoom, like a 300mm or greater.
Best entry-level DSLR
Canon EOS 2000D / Rebel T7
The replacement for the EOS 1300D is a safe bet and typically a few quid cheaper than its Nikon D3500 competitor. Between the two there's not a huge difference in performance, price, or resulting image quality, though, so your choice may be based on price or brand perception alone.
If you want to use the Canon's rear LCD screen to compose pictures then you might as well forget about it here, as this is a to-the-eye and through-the-viewfinder optimised camera - if screen-based shooting is your absolute must then look to a mirrorless camera instead.
Read our preview: Canon 2000D review
Best small-scale DSLR
Canon EOS 200D / SL2
The Canon EOS 200D (or SL2 in the USA) sits in a world of its own, as the update to the small-scale 100D (SL1). It's as small as DSLR cameras come - and that in itself is the single biggest reason for buying it.
This is the DSLR to take up less bag space while delivering quality akin to the EOS 80D model (listed below) thanks to the 24-megapixel sensor on board.
Read our preview: Canon EOS 200D
Best mid-level DSLR
Canon EOS 90D
If you're looking for an all-rounder when it comes to both still images and movie capture then the 90D is one of the best pure DSLRs to cater for such a varied and successful feature set.
Where the 90D really excels is with its autofocus system. The Dual Pixel AF system - which uses on-sensor phase-detection via live view and a different phase-detection system through the viewfinder - comprises 45 autofocus points and is super-fast whether you're looking through the viewfinder or using the rear screen to compose your shots.
Elsewhere the 80D ups the viewfinder ante with a what-you-see-is-what-you-get 100 per cent field-of-view - something cheaper DSLR cameras often lack (like the 2000D and SL2 listed above) - while its vari-angle touchscreen remains one of its strong points, especially in a competitive world against compact system cameras.
Read our full review: Canon EOS 90D review
With a new tilt-angle screen for this level in the company's series, its touch-sensitive controls make it versatile - whether using viewfinder or screen for composition. However, the live view screen-based focus just isn't quite as snappy as the Canon 90D equivalent (above).
Nikon's autofocus system really sells the D7500 though. The second-generation Multi-CAM 3500 delivers 51 AF points that are super quick to acquire subject focus - even in the dark thanks to operability down to -3EV - but that is the same system as found in the earlier D7200 model, which might make that older, more affordable model all the more tempting.
Read our full review: Nikon D7500 review
Best mid-level full-frame DSLR
Sensors the same size as traditional 35mm film negatives are called "full-frame". This large sensor size produces a pronounced depth of field (i.e. more blurred background potential - depending on the lens), while the sensor's "pixels" are typically larger for a cleaner signal and, therefore, usually superior image quality compared to APS-C sensors (this can be resolution dependent though).
Canon EOS 6D Mark II
Perhaps the most versatile full-frame camera you can buy. It's got a great sensor. It's got a vari-angle touchscreen with excellent live-view autofocus for on-screen composition. It's got an autofocus system way better than its 6D predecessor. And it's far cheaper than the 5D MkIV (below).
The Canon's not quite perfect, though. The live view, while fast, isn't as pinpoint perfect when it comes to focus as an equivalent mirrorless camera. Then there's the viewfinder's 98 per cent field-of-view (the outermost two per cent isn't visible in the finder, but is captured), which for a camera of this price is a drawback.
Nonetheless, if you've been thinking about buying a full-frame DSLR but have been waiting for some of the more modern technologies – touchscreen control, a vari-angle screen, Wi-Fi sharing and so on – then the 6D Mark II does a grand job.
Read our full review: Canon EOS 6D Mark II review
Best pro-spec all-rounder (APS-C sensor)
When full-frame 35mm film was settled upon back in the day, it later spawned a smaller format that came to be known as APS-C. By having this half-frame sensor the image produced gives the impression of a greater zoom lens. That's why you'll see some lens' focal lengths described as "35mm equivalent". APS-C is now the most common sensor size, and arguably the most versatile.
The is-it-isn't-it? replacement for the Nikon D300S, the Nikon D500 was one of the most interesting and important DSLR cameras that we've handled. It embodies much of the top-spec ultra-pro Nikon D5 in a smaller format. It's the "D5 mini" if you will. (There is now a Nikon D6, whether that spells a likelihood for a D600, however, is another matter).
Which translates into a whole heap of good things. The 21-megapixel sensor is backed up with the speedy Expeed 5 processing engine and can capture shots up to an extended sensitivity of ISO 1,640,000. Yup, that's six figures.
It's so good we think it steps above the even older Canon EOS 7D Mark II, while the range of Nikon DX optics will see it as the more practical solution compared to the Pentax K-1 for many - even if the Pentax has some standout features like its variable LCD screen.
Read our full review: Nikon D500 review
Best high-resolution DSLR
Nikon did what we thought was utter madness when it announced the 36-megapixel D800 in 2012. But after using it extensively we found its super-high resolution full-frame sensor was an utter marvel. Two years after that came the D810, at the same resolution. The D850, however, pushes things yet further with its 45-megapixel sensor.
In the right hands and with good quality glass, this camera is capable of producing crisp and highly detailed images. The dynamic range is almost unreal, too.
Little changes to the D850's body compared to its predecessor's also transform the user experience. Illuminated buttons, silent shutter mode, deeper grip and class-leading battery life all add up to something quite special.
Its only shortcoming is the live view autofocus speed isn't as capable as Canon's equivalent. And the Canon 5DS (below) crams in yet more resolution, if that's what you're really seeking.
Read our full review: Nikon D850 review
Canon EOS 5DS
If it's resolution you want, not much else in the DSLR world crams more pixels onto a sensor than Canon (there's a 61MP Sony, but it's not technically a DSLR). The 5DS has 50 million of them, making this a DSLR that can rival the medium format market.
And it's really rather brilliant. Shoot with this camera and you'll need to be extra tight with shutter speed control to avoid blur, which is why some of the 5DS's high-flying features - such as the 61-point autofocus system - almost seem mis-matched if you're the kind of user who expects to pick this camera up and snap away as if it's the same as the 5D Mark IV.
Even so, when paired with the right lenses and selecting sufficient shutter speeds the Canon holds up well against the Nikon D850. Plus it has better on-screen live view autofocus, should you be shooting in that format.
Read our full review: Canon EOS 5DS review
Best enthusiast full-frame DSLR
Canon EOS 5D Mark IV
You already know your stuff. You want to take the full-frame sensor plunge or perhaps upgrade from an earlier model but don't have the cash for a crazy-fast pro-spec camera. Yet you still want just enough power in a feature set that's rounded enough to cover sports, portraits, landscapes - the works. Say hello to the 5D Mark IV.
The 5D IV is a deft balance between resolution, image quality, autofocus ability and control, seeing it stand head and shoulders above its predecessor and, right now, much of the competition too. With Nikon's current absence in this market, perhaps only the Sony A99 II or pricier A9 will be an alternative option - but probably not if you're already invested in Canon optics. And there's not a mirrorless model to compete at this level just yet, even if Panasonic is knocking on the door with its G9.
Now the latest 5D is not cheap by any means - an end-of-line Mark III might do you justice instead - but it's got every base covered and that 30-megapixel sensor is not only awesome in good light, it aces low-light conditions too.
Read our full review: Canon EOS 5D Mk IV review
Best professional DSLR (full-frame sensor)
The choices at this level are more or less two-fold if you're considering full-frame: Canon 1D X Mark II or Nikon D5 (further below).
Canon EOS 1D X Mark II
Although a generation old now - there's a new Mark III model - Canon's 1D X II succeeds in the speed stakes, delivering 14fps burst shooting. Its battery life seems to last forever and, importantly, its 20.2-megapixel full-frame sensor is just about perfect for all manner of jobs - rather than being overly resolute. An updated autofocus system - and there's not enough space here to explain its full complexities (take a look at our full review) - hits home with 61 ultra-sensitive AF points and works a treat too.
Some other full-frame models outperform in the resolution stakes, it's questionable as to whether Canon has lost its "movie king" hat, and the Nikon D6 shouts a lot with its nifty autofocus system and low-light capabilities too. With all that said, when it comes to creative professional tools the 1D X series knows its market.
Read our full review: Canon EOS 1D X II review