Mirrorless camera
A mirrorless camera, sometimes referred to as a mirrorless interchangeable-lens camera, is a digital system camera which does not use a reflex mirror to present an image through a viewfinder. They have come to replace DSLRs, which have historically dominated interchangeable lens cameras. Other terms include electronic viewfinder interchangeable lens, compact system camera, and digital single-lens mirrorless.
When compared to similar DSLRs, these cameras can be smaller, lighter, and quieter.
In cameras with mirrors, light from the lens is directed to either the image sensor or the viewfinder. This is done using a mechanical movable mirror which sits behind the lens. By contrast, in a mirrorless camera, the lens always shines light onto the image sensor, and what the camera sees is displayed on a screen for the photographer. Most mirrorless cameras also simulate a traditional viewfinder using a small screen, known as an electronic viewfinder.
DSLRs can act like mirrorless cameras if they have a "live view" mode, in which the mirror moves out of the way so the lens can always shine onto the image sensor.
Many mirrorless cameras retain a mechanical shutter. Like a DSLR, a mirrorless camera accepts interchangeable lenses. Mirrorless cameras necessarily have shorter battery life because they need to power the screen and sensor at all times.
Design
Mirrorless cameras are mechanically simpler than DSLR cameras, and are smaller, lighter, and quieter due to the elimination of the moving mirror. While nearly all mirrorless cameras have a mechanical shutter, many also have an electronic shutter, allowing completely silent operation.As the image from the lens is always projected onto the image sensor, features can be available which are only possible in DSLRs when the mirror is locked up into "live view" mode. This includes the ability to show a focus-peaking display, zebra patterning, and face or eye tracking. The electronic viewfinder can provide live previews of depth of field, exposure, white balance and picture style settings, as well as offer a real time view of camera settings even in extremely low or bright light levels, making it easier to view the results.
With the latest AI autofocus available on newer mirrorless cameras, the autofocus speed and accuracy of newer models has been shown to be better than DSLRs. But mirrorless cameras have shorter battery life than DSLRs due to prolonged use of LCD and/or OLED viewfinder displays. On-sensor autofocus is free of the adjustment requirements of the indirect focusing system of the DSLR, and as of 2025 mirrorless cameras could shoot with AI autofocus at up to 40 frames per second using up to 759 focus points —a number far exceeding what was possible on any DSLR. However, some older mirrorless cameras with on-sensor phase detection autofocus repurposes pixel sites for autofocus acquisition, so that image data is partially or entirely missing for the autofocus "pixels", which can cause banding artifacts in the final image.
History
Early 2000s: Digital rangefinder origins
The first digital rangefinder camera commercially marketed was the Epson R-D1, followed by the Leica M8 in 2006. They were some of the first digital lens-interchangeable cameras without a reflex mirror, but they are not considered mirrorless cameras because they did not use an electronic viewfinder for live preview, but, rather, an optical viewfinder. Compact cameras with large sensors, technically akin to the current mirrorless cameras, were also marketed in this period. Cameras like Sony Cyber-shot DSC-R1 and Sigma DP1 proved that live preview operation is possible, and useful with APS-C sized sensors.file:Lumix G1-IMG 2436.jpg|thumb|Panasonic Lumix DMC-G1Late 2000s: Micro Four Thirds system
The first mirrorless camera commercially marketed was the Panasonic Lumix DMC-G1, released in Japan in October 2008. It was also the first camera of Micro Four Thirds system, developed exclusively for the mirrorless ILC system. The term mirrorless came into use in order to describe Micro Four Thirds cameras when they were announced in 2008, especially as the first Micro Four Thirds camera, the Lumix G1, was designed to be as similar to a DSLR as possible. There are other terms that were created, too, but mirrorless became the most popular.The Ricoh GXR had a radically different design. The mirrorless camera featured interchangeable lens units – a sealed unit of a lens and sensor, instead of the lens only being interchangeable. This design was different from other mirrorless cameras, and received mixed reviews, primarily due to its higher cost.
2010s: Pocket mirrorless cameras
Following the introduction of the Micro Four Thirds system, several other cameras were released by Panasonic and Olympus, with the Olympus PEN E-P1 being the first mirrorless camera in a compact size. The Samsung NX10 was the first camera in this class not using the Micro Four Thirds system, instead utilizing a new, proprietary lens mount. The Sony Alpha NEX-3 and NEX-5 saw Sony enter the market with a new, proprietary lens mount, though the camera included LA-EA1 and LA-EA2 adapters for the legacy Minolta A-mount.file:Pentax Q 02n3000.jpg|thumb|Pentax QIn June 2011, Pentax announced the 'Q' mirrorless interchangeable lens camera and the 'Q-mount' lens system. The original Q series featured a smaller 1/2.3 inch 12.4 megapixel CMOS sensor. The Q7, introduced in 2013, has a slightly larger 1/1.7 inch CMOS sensor with the same megapixel count.In September 2011, Nikon announced their Nikon 1 system which consists of the Nikon 1 J1 and Nikon 1 V1 cameras and lenses. The V1 features an electronic viewfinder. The series includes high-speed mirrorless cameras which, according to Nikon, had the fastest autofocus and the fastest continuous shooting speed of any camera with interchangeable lenses, including DSLRs.
The Fujifilm X-Pro1, announced in January 2012, was the first non-rangefinder mirrorless with a built-in optical viewfinder. Its hybrid viewfinder overlaid electronic information, including shifting frame-lines, to compensate for the parallax effect. Its 2016 successor, the X-Pro2, had an updated version of this viewfinder.file:Samsung NX10.jpg|thumb|Samsung NX10Beyond just consumer interest, mirrorless lens systems created significant interest from camera manufacturers as a possible alternative to high-end camera manufacturing. Mirrorless cameras have fewer moving parts than DSLRs, and are more electronic, which is an advantage to electronic manufacturers, while reducing the advantage that dedicated camera manufacturers have in precision mechanical engineering. Sony's entry level full frame mirrorless α7 II camera has a 24-megapixel 5-axis stabilised sensor, but is more compact and less expensive than any full-frame sensor DSLR.
Canon was the last of the major manufacturer of DSLRs to announce their own mirrorless camera, announcing the Canon EOS M in 2012 with an APS-C sensor and 18 mm registration distance similar to the one used by NEX.
In the longer term Olympus decided that mirrorless may replace DSLRs entirely in some categories; Olympus America's DSLR product manager speculated that by 2012, Olympus DSLRs might become mirrorless, though still using the Four Thirds System.
Panasonic UK's Lumix G product manager John Mitchell, speaking to the Press at the 2011 "Focus on Imaging" show in Birmingham, reported that Panasonic "G" camera market share was almost doubling each year, and that the UK Panasonic "G" captured over 11% of all interchangeable camera sales in the UK in 2010, and that the UK "CSC" sales made up 23% of the interchangeable lens market in the UK, and 40% in Japan.
Sony announced their 2011 sales statistics in September 2012, which showed that mirrorless lenses had 50% of the interchangeable lens market in Japan, 18% in Europe, and 23% worldwide. Since then, Nikon and others entered the mirrorless market.
Due to the downward trend of the world camera market, mirrorless camera sales suffered, but not as drastically and was compensated with increase by about 12 percent in the Japanese mirrorless camera market. However, mirrorless cameras took longer to catch on in Europe and North America. According to Japanese photo industry sources, mirrorless made up only 11.2% of interchangeable-lens cameras shipped to Europe in the first nine months of 2013, and 10.5% of those shipped to the U.S. in the same period. An industry researcher found that mirrorless camera sales in the U.S. fell by about 20% in the three weeks leading up to December 14, 2013—which included the key Black Friday shopping week; in the same period, DSLR sales went up 1%. Looking ahead, the APS-C sensor segment is projected to retain a substantial 47.2% share of .
In 2013, mirrorless system cameras constituted about five percent of total camera shipments. In 2015, they accounted for 26 percent of system camera sales outside of the Americas, and 16 percent within the United States. As of 2023, mirrorless cameras have come to overtake DSLRs as the dominant kind of interchangeable lens camera, with them gaining market share over DSLRs, and nearly all camera manufactures have switched entirely and exclusively to making mirrorless cameras and lenses.
Until the mid 2010s, mirrorless cameras were dismissed by many photographers, because of their laggy and low resolution screens, when compared with the clarity and responsiveness of the optical viewfinders used on DSLRs, especially under strong sunlight or when photographing the sky at night. In addition, mirrorless cameras were known for having worse autofocus performance compared to DSLRs, and much worse battery life. This negative perception of mirrorless cameras began to change around 2013, when the Sony α7 was released. It was the first professional, full-frame mirrorless camera, and, although not the first with depth aware autofocus, included small additional sensors on the main sensor to detect depth in the scene, for fast autofocus.
2015 sales statistics showed that overall camera sales have fallen to one third of those of 2010, due to compact cameras being substituted by camera-capable mobile phones. Within camera sales, mirrorless ILCs have seen their market share increasing, with ILCs being 30% of overall camera sales, of which DSLRs were 77% and mirrorless cameras were 23%. In the Americas in 2015, DSLR annual sales fell by 16% per annum, while mirrorless sales over the same 12-month period have increased by 17%. In Japan, mirrorless cameras outsold DSLRs during some parts of the year. In 2015, mirrorless-cameras accounted for 26 percent of interchangeable-lens camera sales outside the Americas, although a lesser share of 26 percent was in the U.S.
In late 2016, Olympus announced their OM-D E-M1 Mark II camera, a successor to the earlier and successful Mark I. The Mark II model retains a Micro Four Thirds image sensor of 17.3x13 mm and features a 20.4 megapixel resolution sensor, representing a new generation of mirrorless cameras competitive with and in many respects superior to DSLR cameras.