Mirrorless vs DSLR cameras: what's the difference?

When you think of professional photography, often a DSLR comes to mind. However, mirrorless cameras are becoming increasingly popular. 

The difference in image quality between the two is narrowing and technological advancements are pushing many in favour of mirrorless cameras rather than the traditional DSLRs. We've compared them to help you understand the differences and make a choice between the two.

What are the main differences between the two cameras?

Digital single-lens reflex (DSLR) and mirrorless (often referred to as compact system) cameras are both interchangeable lens cameras, with features for more advanced photography. There are a range of models available for each, from those aimed at entry-level photography enthusiasts to professionals.

Both cameras typically have big sensors, allowing them to let in more light and essentially capture more detail than a standard digital camera.

The main difference between the two is that DSLR cameras have a reflex mirror inside them, which bounces light up into the optical viewfinder. With a mirrorless camera, light goes directly into the image sensor and they will have an electronic viewfinder or LCD monitor to display a preview of the image.

What are the pros and cons of DSLRs and mirrorless cameras?

Despite mirrorless cameras becoming more widely available and closer to DSLR cameras in quality, there are pros and cons to both. 

With an ‘old-school’ DSLR, there tend to be perks, which is most noticeably the superior speed when autofocusing or tracking subjects – although this is changing. 

Traditionally DSLR cameras use ‘phase detection’ autofocus modules in the body of the camera, which make autofocusing and tracking subjects fast. 

Mirrorless cameras rely on sensor-based autofocus, which analyses the maximum contrast between pixels on the camera’s sensor. When the contrast is highest, the subject is in focus. This method is traditionally slower and also tends to struggle with moving subjects, as it doesn’t involve measuring distance, just the level of contrast. 

However, advancements in high-end cameras will see ‘hybrid’ autofocus systems featuring in the best mirrorless cameras, narrowing the gap between the autofocusing speeds of DSLR and mirrorless cameras.

That said – there is a reason why DSLR cameras continue to be manufactured and stay the favourite of both amateurs and professionals; we’ve summarised this in our pros and cons below.

Pros of DSLR cameras

• DSLRs have optical viewfinders, which don’t have the risk of delay
• Traditionally they have faster autofocus and tracking subjects (although the gap between the two is closing)
• There’s a larger library of lenses and accessories available for DSLRs

Cons of DSLR cameras

• They tend to be bulky and heavy
• High-end DSLR models can be very expensive
• DSLRs often have slower continuous shooting speeds

If you prefer shooting via a traditional viewfinder and like to see a wide selection of accessories and lenses available, a DSLR is the way to go. If shooing via viewfinder, you can also be confident that autofocus is going to be at its very best. 

We've rounded up the DSLR cameras which have performed the best in our testing, below. 

Pros of mirrorless cameras

• Many mirrorless cameras have an electronic viewfinder that shows an accurate preview of the final image
• Mirrorless cameras are often smaller and lighter than DSLRs
• Generally they’re less expensive than DSLRs
• Mirrorless cameras often have fast continuous shooting
• You’ll get better video quality thanks to better live view autofocus and entry-level mirrorless models more often support 4K
• They tend to have more scene modes and automatic settings

Cons of mirrorless cameras

• Some mirrorless models don't have a viewfinder
• Electronic viewfinders can experience delay
• Mirrorless cameras often have fewer quick-access dials/buttons
• There’s a smaller collection of lenses and accessories for mirrorless cameras available
• Mirrorless cameras have a shorter battery life

If you need interchangeable lenses but want something lighter and more compact, mirrorless is your best option. The gap between DSLR and mirrorless cameras is constantly closing, so you won't be compromising on picture quality. 

Just bear in mind you might not always find a viewfinder and, if you do, you might experience some lag. 

To help you choose the best mirrorless model, read on to see our top three.