Iconasys, a leading developer of still and 360 product photography equipment and software, develops and sells tools that enable users of any skill level to easily and efficiently create high quality product images, 360 product views, interactive 360 product videos and 3D models in house. Our line of Product Photography Software connects a digital camera to a computer and automates the process of capturing and editing images. The Product Photography Software supports a wide range of cameras, including mirrorless cameras from Nikon, Canon and Sony. In this article, we provide a high-level overview of the differences between standard digital single-lens reflex camera (DSLR) cameras and the new mirrorless digital cameras.
First, the most noticeable difference is that the mirrorless camera has no mirror between the sensor and the lens. As a result, the mirrorless camera tends to be shallower, in the direction of the lens, than its DSLR counterpart.
The DSLR camera uses a mirror to redirect the light from the lens to the viewfinder. This provides an optical, or analog, preview of the image in the viewfinder. When the image is captured the mirror swings up and the image is captured by the sensor that sits behind the mirror.
In a mirrorless design the light is processed by the sensor at all times and the viewfinder shows the preview image as a digital image, rather than the analog image seen in a DSLR. A mirrorless camera provides only a digital preview and does not offer an optical, or analog, preview in the viewfinder. The lack of a mirror and analog preview in a mirrorless camera has implications that are discussed next.
Before comparing differences and similarities between mirrorless and DSLR designs, it is important to note that a DSLR camera can act like a mirrorless camera when the DSLR camera is in Live View mode – a feature common in all modern DSLRs. In Live View mode, the DSLR’s mirror is moved up, blocking the viewfinder, and the DSLR camera’s functionality acts like a mirrorless camera. With Live View mode enabled a DSLR camera is a mirrorless camera without a preview in the viewfinder. The rest of the article focuses on the differences between DSLRs and mirrorless designs, assuming the DSLR is not in Live View mode.
Second, in a mirrorless camera the preview is obtained after the sensor digitizes the image and the camera’s central processing unit (CPU) processes it. This slight delay may make the camera’s preview feel a bit less responsive than the DSLR’s preview.
Third, in a mirrorless design the preview image comes after the CPU processes the captured image and therefore the preview shows the actual exposure. The preview in a mirrorless camera tends to be more accurate than in a DSLR design.
Fourth, in a mirrorless camera, the auto focus tends to be more accurate and less prone to loss of calibration over time, than in a DSLR. In a mirrorless camera the focus system works directly with the sensor, while in a DSLR design the focus system is located away from the sensor. In Figure 2 (credit: Digital Photography School) the red line shows the path light takes in a DSLR camera. The light passes through the lens and the DSLR’s mirror system sends the light up to the viewfinder and to the focusing system – the downward pointing red ray. Due to the wear and tear that may happen in the mirror system, a DSLR camera may need to have its auto focus adjusted from time to time.
It is interesting to note that comparing the auto-focus speed of two mid-range full frame DSLR cameras with mirrorless cameras, the DSLRs tend to have faster auto focus speeds, than the mirrorless designs, but technology is fast evolving. There are some high-end mirrorless cameras that can shoot as fast as DSLRs or in some cases much faster, for example the mirrorless Sony A9. (For a good discussion on DSLR and mirrorless focusing technology, we recommend the article 3 Reasons Why Mirrorless Cameras are Better than Digital SLRs for Focusing and encourage readers to read the discussion section, at the end of the article, as well.)
Fifth, mirrorless cameras can shoot more silently, due to the lack of moving mirrors.
Sixth, there’s no real difference between mirrorless and DSLR shutters. Generally speaking, the same shutter technology can be used for either camera design. Mechanical, rolling shutters are used in most cameras, due to their higher speeds. Electronic shutters tend to be used for lower shutter speeds, including videos. Shutter technology in itself, is a fascinating topic and for interested readers we’d recommend these articles: How Do Camera Shutters Work? and Why Leaf Shutter Lenses Matter.
Seventh, the battery life in mirrorless cameras tends to be shorter than in DSLRs. In a mirrorless design the CPU needs to be on for preview processing, whereas in a DSLR the CPU processes the digital image only at capture time.
Eighth, in a mirrorless design, micro-vibrations caused by the moving mirror in a DSLR design, is eliminated. (Reminder here, that when Live View is enabled in a DSLR, the mirror is pushed up for preview purposes. In an earlier article, Product Photography Background Removal Using Shutter Stream and a Background Image, we recommended that for the most accurate images users should turn on digital preview on their DSLRs. This is because with a digital preview the mirror is pushed up and mirror slap is eliminated. This minimizes sensor vibration at shooting time and increases overall image quality – noticed especially when shooting macro photography).
Ninth, in a DSLR design the mirror tends to protect the sensor from dust and scratches during lens changes. In a mirrorless design the sensor is exposed, and extra care should be taken when changing lenses, in order to minimize sensor damage.
| Feature | Mirrorless | DSLR | Notes |
| Size and weight | Smaller | Larger* | *Due to mirror system |
| Analog preview | No* | Yes | *The viewfinder in a mirrorless camera shows a digital preview. |
| Digital preview in viewfinder | Yes | No* | *With Live View enabled, a DSLR has a digital preview on the LCD. |
| Auto focus accuracy | Higher | Less* | *Assuming Live View disabled. |
| Shooting noise | Quieter | Noisier* | *Assuming Live View disabled. |
| Battery life | Less | More* | *Assuming Live View disabled. |
| Sensor damage when changing lenses | Higher | Less* | *Mirror is down, protecting the sensor, when power is off in a DSLR. |
| Prone to wear and tear | Less | More* | *More prone due to the potential in failure of the mirror system. |
Figure 4: Summary of features between mirrorless and DSLR designs.
In conclusion, this article highlighted some of the main differences between the mirrorless and DSLR designs, as shown in Figure 4. The main advantages of mirrorless over DSLRs are: smaller body, more accurate previews, more accurate auto focus, more silent shooting, less prone to mechanical failure due to the failure of the mirror system, less camera vibrations during shooting and the potential for much faster shooting speeds by removing the dependency on mechanical parts. The main advantages of DSLRs over mirrorless are potential for longer battery life, instant preview response in the analog viewfinder and, with Live View enabled, a DSLR acts as a mirrorless design without the digital preview in the viewfinder.
About the author: Robert Solymosi is a member of the Iconasys software development team and an avid photographer. He owns a Nikon Z6 and loves his mirrorless camera.
