Why switching to Mirrorless Cameras from DSLR is unavoidable?

Until quite recently, DSLR cameras were the industry standard and you probably never even considered that they would be replaced by newer technology. Today, however, mirrorless cameras are being widely adopted by photographers. If you’re accustomed to DSLR, should you make the switch? Let’s have a look based on certain parameters.

Mirror

DSLRs and mirrorless cameras both show the scene through the camera lens itself as you compose the picture, but the way they display it is completely different. DSLRs use a mirror to reflect an optical image up into the viewfinder. You are looking at an optical image. When you take a picture, the mirror flips up so that the image can then pass to the back of the camera where the sensor is exposed to the image.

A distinct approach is taken by mirrorless cameras. They produce an electronic image from the "live view" recorded by the camera sensor itself that can be viewed on the back screen or in an electronic viewfinder. There isn't a mechanism for the mirror to flip up and out of the way.

What appears to be a win-win scenario, however, is a little more difficult than that. First off, a lot of individuals choose the optical image provided by a DSLR viewfinder. Second, digital displays use a lot more energy, and mirrorless cameras still don't have the same battery life as DSLRs.

Autofocus 

The main distinction is that DSLRs, confusingly, need the use of two autofocus systems, whereas mirrorless cameras use a single autofocus system for both rear screen and viewfinder photography.

DSLR cameras have special "phase detect" autofocus sensors built into the base of the camera, behind the mirror. The AF sensor is no longer accessible when you take a picture since the mirror folds up and out of the way.

This wasn't an issue back when DSLRs lacked live view. DSLRs were forced to move to autofocus technologies that employed the image created on the sensor directly as demand for live view shooting with the rear screen increased.

DSLRs only have one autofocus system, which is a circumstance that still exists today.

So you have a situation that still exists today: DSLRs have two autofocus systems, one for the viewfinder and the other for shooting in live view.

Mirrorless cameras have largely caught up to DSLRs in terms of autofocus speed, and they outperform them in terms of frame coverage and tracking capabilities.

Fast-moving sports and action photography, which formerly required a DSLR, may now be successfully captured with mirrorless cameras. Even DSLR sceptics would have to admit that the separate phase-detect AF systems in DSLRs are archaic in comparison to the hybrid on-sensor autofocus technology in the most recent Sony A7 IV(opens in new tab).

Viewfinder

Mirrorless cameras must employ electronic viewfinders due to their design. These have significantly improved in a very short period of time.

The newest and greatest electronic viewfinders currently on the market have a resolution so high that you hardly notice the "dots," and their clarity really approaches that of optical viewfinders.

 They may still experience lag, also known as "latency," which is a slight gap between what the camera sees and what the screen displays. Faster refresh rates have made viewfinder lag less of an issue than it once was, and most recently, manufacturers have been concentrating on the blackout effect you would often see when shooting continuous bursts of photographs. On the Sony A9 model (opens in new tab), Sony was able to do so, and Panasonic says the same for the Lumix G9 model (opens in new tab).

Two very underappreciated advantages of electronic viewfinders are their ability to provide a more clearly visible image of a scene in low light and their zoom functions for fine manual focusing. Electronic viewfinders enable you to prepare and take pictures in nearly complete darkness thanks to their auto-gain light amplification effect, and they have made small-aperture telephoto lenses like the Canon RF 600mm f/11 and RF 800mm f/11 extremely useful.

A DSLR viewfinder will be far too dark if you prefer vintage manual lenses that must be used in stopped-down mode, but a mirrorless EVF will work just perfectly. Another significant benefit of optical viewfinders is crucial for sports and action photographers in particular. The mirror flipping up and down between exposures causes an unavoidable screen blackout in the camera's burst shooting mode, but this is rarely a problem. The important thing is that there is no lag, and it is much simpler to follow a fast-moving subject with a high-speed DSLR like the Nikon D500(opens in new tab) than it is with the typical mirrorless camera.

Lenses

Considering that DSLRs have been available and supported for so long, they still have an advantage in terms of lens selection. Today, anyone using a Canon EOS DSLR has access to 30 years' worth of native optics, and many more when compatible third-party options are taken into account. With their DSLR lineups, Nikon and Pentax are in a comparable situation.

 But the production of new DSLR lenses has drastically decreased. Nearly all of the lens development work that Canon and Nikon do now is for mirrorless lenses. In addition, lens designers now have a clean canvas thanks to wider mirrorless lens mounts and shorter back-focus 'flange' distances, and many modern mirrorless lenses perform better than their DSLR equivalents.

Simply because they have been around and maintained for so long, DSLRs still have more lens options. The native optics available for the Canon EOS DSLR currently span 30 years, and there are many more when suitable third-party alternatives are taken into account. With regard to their DSLR product lines, Nikon and Pentax are in a comparable situation. 

The creation of new DSLR lenses has, however, slowed significantly. Nowadays, mirrorless lenses receive practically all of Canon and Nikon lens development efforts. And many modern mirrorless lenses perform better than their older DSLR equivalents because of wider mirrorless lens mounts and shorter back-focus 'flange' distances.