What is the Difference Between a Mirrorless and DSLR Camera?

We explain the differences between these two types of cameras and tell you which is best for your specific needs.

by K. Cardinalis
on June 27, 2018

For a long time, DSLRs were considered the gold standard of digital cameras. While older point-and-shoots had their advantages, those with the budget for a DSLR camera could look forward to higher-quality images, improved light sensitivity, and the ability to compose an image while viewing it directly through the lens.

But nowadays, there is a new class of cameras making a foray into the market. “Mirrorless” cameras are swiftly rising to compete with DSLRs when it comes to quality and convenience.

If you’re trying to figure out which type to buy, it can be easy to get swept up in the complexities of the technical terminology.

In this guide, I will introduce you to the key differences between DSLR and mirrorless cameras. That way you can select the camera which is most suited to your needs. Let’s start out by outlining some basic definitions.

  • DSLR is an abbreviation for “digital single-lens reflex.” DSLR cameras work the same way as traditional film-based single-lens reflex (SLR) cameras. The difference is that the film has been exchanged for a digital imaging sensor. DSLR cameras contain a mirror. When you look through the camera, the mirror is reflecting the light streaming into the lens to the viewfinder. If you decide to snap a photo, the mirror transfers the light to the sensor. The sensor then records the shot.
  • As their name implies, mirrorless cameras do not contain a mirror. That means there is no way to look through a viewfinder at an optical image. Instead, you look at an electronic image displayed on an LCD screen on the back of the camera. Many mirrorless models nowadays are equipped with viewfinders, but these too display an electronically generated image.

That right there—a mirror or the lack of it—is the key distinction on a technical level dividing DSLR cameras from mirrorless ones.

The lack of a lens in mirrorless cameras has a number of implications when it comes to image composition, size and weight, and other attributes, which I will go over in just a moment.

Before I do, I want to briefly address the matter of point-and-shoot cameras. If you think mirrorless cameras sound a lot like point-and-shoot cameras, you’re right—an argument can be made that the two categories overlap.

Indeed, you could say that a mirrorless camera is essentially a next generation point-and-shoot. It works the same way, but it includes some enhanced features. Interchangeable lenses make for the key defining difference, though many mirrorless cameras also include larger sensors and electronic viewfinders than those which are lumped into the “point-and-shoot” category.

Comparing DSLR and Mirrorless Cameras

Now that you understand what DSLR and mirrorless cameras are and how they work, let’s take a look at which cameras are best in a range of categories. This should help you decide on a practical level which type of camera is best suited to your needs.

DSLR Cameras are Best For:
  • Lenses. When it comes to lenses, it is still hard to beat a DSLR. You should be able to find pretty much any type of lens you need for many popular models of DSLR cameras. That said, even though DSLRs are still best when it comes to lens selection, there are fairly extensive lines of lenses available for some mirrorless cameras now.
  • Optical viewfinder. You get a traditional, optical viewfinder with a DSLR camera. Some photographers have a strong preference for this “true” view for image composition. They do not want to see the image “in translation” electronically.
  • Auto-focusing. With their powerful phase detection modules for auto-focusing, DSLR cameras remain the best in this category. Mirrorless cameras are not bad for auto-focusing, but still do not perform at the same caliber as their DSLR counterparts.
  • Megapixels. At present, DSLR cameras are still in the lead when it comes to resolution. The Sony Alpha A7R III mirrorless camera is capable of 42.2MP, but the Canon EOS 5Ds DSLR can capture 50MP. Currently it is unsurpassed.
  • Battery. You can expect to shoot anywhere from 600-1,000 photos before you need to switch out the battery on a DSLR, but you will probably need to change a mirrorless camera battery after only around 300-400 photographs.
Mirrorless Cameras are Best For:
  • Electronic viewfinder. Some people actually prefer electronic image previews over optical viewfinder images. They are information-dense and can display data which would never be available through an optical viewfinder. Note however that if there is no electronic viewfinder (just an LCD screen on the back of the camera), it can be hard to see what you are doing in bright light conditions.
  • High-speed photography. If you want to capture high-speed subjects, you can’t beat the high frames per second possible on a mirrorless camera. You can get as high as 20fps on mirrorless models like the Sony Alpha A9, but DSLRs have yet to surpass 14fps.
  • Video. With an increasing number of models capable of 4K, mirrorless cameras are the superior choice for capturing video.
  • Compact, convenient design. Mirrorless cameras without viewfinders can be compact and lightweight compared to DSLR cameras.
To sum up:
  • Consider a DSLR if you prefer a traditional viewfinder, build, and feel, and if you want the widest possible selection of lenses. DSLRs also have some advantages when it comes to auto-focus, battery and resolution.
  • Think about getting a mirrorless camera if you prefer a compact design and an electronic viewfinder. For high-speed photography and video, mirrorless cameras are clear winners.
  • In terms of features and control over image settings, neither type of camera is necessarily superior. Both mirrorless and DSLR cameras offer comparable features and settings on the whole, though at the entry level, a DSLR will typically give you more for the money (you get a viewfinder, plus better resolution and battery life). At the higher end, the technical specifications for mirrorless cameras tend to leave DSLRs behind.
  • Conclusion

    You now know the key differences between mirrorless and DSLR cameras in terms of build, function and specifications. Neither type of camera is “better” in a broad sense. Ultimately, it comes down to personal preference. So think about what you like to photograph and how you like to shoot, and pick a camera which will fit your needs.