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1 October 2020

How we test DSLR and mirrorless cameras

Find out how we test DSLR and mirrorless cameras to separate those that put you in a position to take fantastic photos, from the duds that let you down.
Ryan Shaw

What makes a Best Buy DSLR or mirrorless camera?

A mirrorless or DSLR camera is a big investment – you’re not just buying a camera, but investing in a system of lenses and accessories that you may be using for many years to come. That’s why we recommend the cameras you can trust to help you take great pictures and support you in your photography. 

We look for sensors that make the most of the light in every scene, and the features and controls that enable you to get a brilliant photo in an instant, but also give you the creative power when you want it. While we want faster shutter speeds, higher ISO settings and a fast, precise auto-focus, we don’t forget about the basics. What is the kit lens like? Is it easy to grip? How hard is it to replace the batteries? The video above shows how choosing a Best Buy DSLR or mirrorless camera can make a massive difference to your photos.

We conduct around 450 tests per camera and ensure that every DSLR and mirrorless camera goes through the exact same tests, combining assessments from image-quality experts with rigorous technical lab tests. We ensure that every camera review answers all the key questions you might have, including:

  • Does this DSLR or mirrorless camera take great photos?
  • How easy is this DSLR or mirrorless camera to use?
  • Can I see what I need to in the monitor and/or viewfinder?
  • Does this DSLR or mirrorless camera shoot great video, and does the audio match up?
  • How effective is the built-in flash?
  • Will its features help me take better photos?
  • Should I buy it?

Don't settle for anything less when it comes to image quality - find a superb DSLR or mirrorless camera that takes first-class stills and videos from our Best Buys.

Does this DSLR or mirrorless camera take great photos?

With DSLR and mirrorless cameras, photo quality is paramount – we expect the best of the best. We take photos in a range of conditions, including in bright outdoor natural light, indoors and in low light. And we try the camera with different settings, using the bundled kit lens at both its wide-angle and telephoto settings, and using the camera in both automatic and manual modes. 

We also measure image resolution and look for potential problems, such as distortions, with the camera at different settings eg, wide angle or telephoto. All of these tests help us differentiate the cameras you can rely on to take sharp, well-balanced photos in any situation from those that will let you down as soon as the light levels drop. Our Best Buy DSLRs and mirrorless cameras produce great photos whether you’re shooting inside or outside, in sunlight, twilight or under artificial light.

How easy is this DSLR or mirrorless camera to use?

We don’t expect every DSLR or mirrorless camera to be a novice photographer’s dream, but we do expect them to have quick and intuitive controls, well-placed buttons and dials, a comfortable grip for steady shooting, logical menus and a good range of features. If those features make it easier for less experienced photographers to take good photos, all the better. 

We also look at how easy it is to insert a memory card or change the batteries, and we measure how fast the camera is to start up and how quickly the shutter reacts when you press the shutter release button. Is it quick enough to make sure that you get the shot you want, and is there enough feedback to know when you have your subject in focus and ready to shoot? We also time how quickly it can rattle off a burst of shots, so that you don’t miss the perfect fast action or wildlife photo.

Can I see what I need to in the monitor or viewfinder?

Most DSLRs come with a viewfinder but still rely on a monitor for reviewing photos and changing settings, as well as having the option to use the monitor to frame and capture images instead. Mirrorless cameras often have electronic viewfinders and some only rely on monitors. We check both carefully to see whether they provide the clarity, field of view and detail you need to help you compose your photos and make creative decisions. We also assess them both in low light and bright sunlight, to ensure that our Best Buys can be used in any situation.

Does this DSLR or mirrorless camera shoot great video, and does the audio match up?

Even professional video makers are now using DSLR and mirrorless cameras, attracted by their great image quality and high-quality lenses. We set each DSLR and mirrorless camera to shoot video of two different scenes at a range of different quality settings, looking for whether it can capture fine detail and colour in clothing or objects, while checking how well it handles fast movement. We pan the camera around to see whether the picture holds up, or whether it becomes jerky. 

We also assess and rate the audio captured by the built-in microphone, listening carefully to see whether any noise is picked up from the auto-focus or the buttons, and whether the sound is clear and rich or dull and muted.

How effective is the built-in flash?

Where a DSLR or mirrorless camera has a built-in flash we put it through its paces to see how well it adjusts its brightness for different conditions, so that you don’t end up with shiny-looking skin in portraits or underexposed photos when you shoot indoors. We also take a photograph at different distances, from close up to over 10m away, to see how the flash behaves at different ranges. Does it go too bright close up, or does it lose its power when at a distance? Do any unwanted reflections from it creep into the shot?

Will its features help me take better photos?

Manufacturers claim that their DSLR or mirrorless camera's features will help you take better photos. We put those claims to the test. We test face-detection features to see whether they help you take well-exposed, sharp portraits, or whether they hinder you. We also test image-stabilisation features by putting the camera on a vibrating platform and run it 900 times, identifying how well it handles the ultimate pair of shaky hands.

Should I buy it?

All the tests above contribute towards a total test score, which enables us to pull the best and worst cameras from the pack. We focus on image quality, ease of use, video and audio, viewfinder and monitor quality and flash. We don’t figure price into the equation. The total score breaks down as follows:

  • 45% image quality
  • 30% ease of use
  • 10% viewfinder & monitor
  • 10% video/audio quality
  • 5% flash 

A DSLR or mirrorless camera must score 76% or higher to earn our Best Buy recommendation. DSLR or mirrorless cameras that score 45% or lower are a Don’t Buy, because we think they’re best avoided.

View all DSLR and mirrorless cameras