In the world of photography, mirrorless cameras have emerged as a game-changer. What is a mirrorless camera? It’s a type of digital camera that captures images without using a reflex mirror, unlike traditional SLR cameras.

These innovative cameras often incorporate electronic viewfinders (EVFs) to display images digitally, making them more compact and offering potentially superior image quality compared to SLRs, as the lens sits closer to the sensor without a mirror in between.

What is a Mirrorless Camera?

Defining Mirrorless Cameras

A mirrorless camera, like the Fuji X-H2, also known as a mirrorless interchangeable-lens camera (MILC) or single-lens mirrorless (SLM), is a type of digital camera that captures images without using a mirror mechanism. Unlike traditional SLR cameras, which reflect the image from the lens onto an optical viewfinder using a mirror, mirrorless cameras project the image directly onto the image sensor.

Key Components and Functionality

  1. Sensor: Mirrorless cameras have an image sensor, similar to SLRs, that captures the light coming through the lens.
  2. Electronic Viewfinder (EVF): Instead of an optical viewfinder, mirrorless cameras often feature an electronic viewfinder that displays a digital preview of the image captured by the sensor.
  3. LCD Screen: Mirrorless cameras typically have a large LCD screen on the back, which can be used for composing shots and reviewing images.
  4. Interchangeable Lenses: Like SLRs, mirrorless cameras allow users to swap lenses, providing flexibility and versatility for different shooting scenarios.
  5. Autofocus System: Mirrorless cameras use advanced autofocus systems that rely on the image sensor to detect and track subjects, often offering faster and more accurate focusing capabilities.

Difference from SLR Cameras

FeatureMirrorless CameraSLR Camera
Mirror MechanismNo mirrorUses a mirror to reflect light into the optical viewfinder
Viewfinder TypeElectronic viewfinder (EVF) or LCD screenOptical viewfinder
Size and WeightGenerally smaller and lighterLarger and heavier due to the mirror box
Lens MountShorter flange focal distanceLonger flange focal distance
Video PerformanceDesigned for better video capabilitiesTraditionally focused on still photography
Live ViewAlways in live view modeLive view mode requires mirror lock-up

Mirrorless cameras offer several advantages, such as a more compact and lightweight design, advanced video capabilities, and the ability to provide a live preview of the image on the sensor. However, SLRs still hold advantages in areas like battery life, optical viewfinder performance, and a wider selection of lenses and accessories.

How Mirrorless Cameras Work

Light Path and Image Sensor

In a mirrorless camera, light enters through the lens and falls directly onto the image sensor, without being reflected by a mirror. The image sensor captures the light and converts it into an electronic signal. This signal is then processed by the camera’s internal processor to create a digital image.

Electronic Viewfinder (EVF) Mechanism

Instead of an optical viewfinder, mirrorless cameras employ an electronic viewfinder (EVF). The electronic signal generated by the image sensor is processed and displayed in real-time on a small, high-resolution electronic display located inside the camera. This display acts as the viewfinder, allowing you to see exactly what the image sensor is capturing.

The EVF provides a real-time preview of the image, including exposure settings, depth of field, white balance, and any other effects applied to the image. This feature enables you to adjust settings on the fly and see the final image before you take the shot.

Shutter and Exposure Process

Mirrorless cameras can use either a mechanical or an electronic shutter to control the exposure time. With a mechanical shutter, a physical curtain opens and closes to expose the sensor to light for the desired duration. Some mirrorless cameras also offer an electronic shutter option, which achieves the same effect by rapidly turning the sensor on and off.

The electronic shutter allows for faster continuous shooting rates and silent operation, making it advantageous for certain scenarios like sports photography or situations where discretion is required. However, it can also introduce rolling shutter artefacts when capturing fast-moving subjects.

Regardless of the shutter type, the exposure process in a mirrorless camera is similar to that of a SLR. You can control the exposure by adjusting the shutter speed, aperture, and ISO settings, and the camera will calculate the appropriate exposure based on the available light.

Advantages and Disadvantages

Advantages (Compact Size, Silent Operation, Better Autofocus, etc.)

  1. Compact and Lightweight Design: One of the primary advantages of mirrorless cameras is their compact and lightweight nature. By eliminating the bulky mirror mechanism found in SLRs, mirrorless cameras can be significantly smaller and lighter, making them ideal for travel, street photography, and situations where mobility is crucial.
  2. Silent Operation: Mirrorless cameras offer a significant advantage with their silent shooting modes, allowing photographers to capture images without making any audible shutter noise. This feature is invaluable for street, event, and concert photographers who need to remain unobtrusive and avoid distracting their subjects.
  3. Advanced Autofocus Systems: Mirrorless cameras boost significantly improved autofocus systems compared to traditional SLRs. By utilising on-sensor phase-detection autofocus, these cameras can focus faster and more accurately, even in challenging low-light situations. Many mirrorless cameras also offer advanced features like face and eye-tracking autofocus, ensuring sharp and precise focus on the subject’s face or eyes.
  4. Real-time Preview and Composition: With their electronic viewfinders (EVFs) and live view on the LCD screen, mirrorless cameras provide a real-time preview of the image as it will be captured, including exposure settings, depth of field, and any applied effects. This feature allows for more accurate composition and easier manual focusing.
  5. Video Capabilities: Mirrorless cameras are designed with advanced video capabilities in mind, offering features like continuous autofocus during video recording, high-resolution video modes, and the ability to use the electronic viewfinder while recording, which is not possible with many SLRs.

Disadvantages (Battery Life, Limited Lens Selection, Low-Light Performance, etc.)

  1. Battery Life: One of the main disadvantages of mirrorless cameras is their relatively shorter battery life compared to SLRs. The electronic viewfinder and advanced autofocus systems can drain the battery quickly, requiring photographers to carry extra batteries or invest in high-capacity battery packs.
  2. Limited Lens Selection: While the lens selection for mirrorless cameras has been steadily improving, it is still more limited compared to the vast range of lenses available for SLRs, especially from third-party manufacturers.
  3. Low-Light Performance: Traditionally, mirrorless cameras have been built with smaller sensors, which can result in poorer low-light performance compared to SLRs with larger sensors. However, recent advancements in sensor technology have significantly improved the low-light capabilities of mirrorless cameras, narrowing the gap with SLRs.
  4. Electronic Viewfinder Limitations: While electronic viewfinders (EVFs) offer many advantages, they can sometimes lag or exhibit artefacts in low-light conditions or when shooting fast-moving subjects. Additionally, some photographers may prefer the optical viewfinder experience of SLRs.
  5. Potential Shorter Lifespan: Since mirrorless cameras rely heavily on electronic components, there is a concern that they may have a shorter lifespan compared to SLRs, which have fewer electronic components that could degrade over time.

It’s important to note that the advantages and disadvantages of mirrorless cameras can vary depending on the specific model and manufacturer, and personal preferences and shooting requirements play a significant role in determining the suitability of a mirrorless camera for a particular photographer.


Mirrorless cameras have undoubtedly revolutionised the photography landscape, offering a compelling blend of cutting-edge technology and exceptional image quality in a compact and lightweight form factor. With their advanced autofocus capabilities, silent operation, and real-time preview, these cameras cater to a wide range of photographic disciplines, from street and event photography to high-end videography. While they may have their limitations, such as shorter battery life and a more limited lens selection compared to SLRs, the advantages they bring to the table often outweigh these drawbacks for many photographers.

As technology continues to evolve, the lines between mirrorless and SLR cameras are becoming increasingly blurred, with both systems striving to incorporate the best features and innovations. Ultimately, the choice between a mirrorless or SLR camera will depend on individual preferences, shooting requirements, and personal shooting style. Regardless of the chosen system, the advancements in digital photography have empowered photographers to capture stunning images and push the boundaries of creativity in ways never before possible.