Mirrorless Systems Guide 2024

Micro Four-Thirds is the original mirrorless system. It was launched in 2008 jointly by Olympus and Panasonic. This head start, plus the fact that it is actively developed by two major digital camera manufacturers, make it the most extensive mirrorless system in terms of cameras and even more so when it comes to lenses.

The standard behind Micro Four-Thirds is based on an older system used by now discontinued Olympus DSLRs. Both these platforms were designed for a 2X crop-factor and 4:3 aspect-ratio. The name Four-Thirds refers to this aspect-ratio, while the term Micro was added to describe a shorter flange distanceThe distance between the sensor and lens mount. but the intended sensor-size is identical. Physics puts Micro Four-Thirds at a 2-stop disadvantage in comparison to Full-Frame and just over ½-stop compared to APS-C.

Panasonic & Olympus Mirrorless Cameras

Panasonic and Olympus continuously introduce new Micro Four-Thirds cameras. They each maintain multiple series of Micro Four-Thirds mirrorless digital cameras, from entry-level to high-end professional models. Olympus added last year the OM-D E-M1X reviewed here
Olympus OM-D E-M1X for professional action photographers.

The approach taken by these two companies differs on several key features. Panasonic used Contast-Detect AF on every single one of their mirrorless cameras. They invented the Depth-from-Defocus technology to improve the performance of Contrast-Detection. Olympus added Phase-Detect AF to many of their cameras, although Contrast-Detect remains in use among their entry-level offerings. With state-of-the-art sensors, there is little performance difference left between these two AF systems.

All Olympus mirrorless cameras feature built-in image-stabilization. They have been perfecting their system for years and now offer best-in-class stabilization with up to 7-stops of efficiency using a 5-axis sensor-shift system assisted by GPS. Panasonic initially went with in-lens optical image-stabilization until they added IBIS to the GX8 in 2015. Since then, 2/3 of their new Micro Four-Thirds mirrorless cameras include it.

When Panasonic started with built-in stabilization, they invented Dual IS which combines both in-body and optical stabilization to deliver further improvements. Olympus later implemented an equivalent system. This required collaboration between the camera and lens, so it is not available on all body and lens combinations.

Olympus Mirrorless Series

The Olympus lineup is divided onto the entry-level PEN series and the OM-D class which is split among three levels of advanced cameras. Olympus has the tradition of making feature-rich cameras with advanced functionality across the board. Even their PEN mirrorless series offers extensive bracketing options, advanced metering modes, Bulb exposure and much more. Except for one, Olympus PEN have limited external controls with just a single control-dial, few buttons and no built-in viewfinder. Some models supported an Optional EVF but no current one does.

The Olympus PEN F
Olympus PEN F is alone in the PEN series in that it features a built-in EVF with Eye-Start Sensor plus dual control-dials and numerous external controls. Although launched in 2016, it still packs the highest Micro Four-Thirds resolution sensor and a 5-axis image-stabilization mechanism effective to 5-stops which remains among the top-performing ones.

There are 3 branches of OM-D plus one unique camera. Smaller numbers are more advanced models. The E-M10 series, now at Mark III
Olympus OM-D E-M10 Mark III, are the smallest and the only not weatherproof OM-D. Like all OM-D, these mirrorless still offer dual control-dials and feature built in EVF with Eye-Start sensor. The mid-range E-M5 series looks incredibly similar yet with better components including high-magnification EVF optics, more effective image-stabilization and a weatherproof body. These improvements almost double the price with the E-M10 Mark III currently selling for $650 USD and the Olympus OM-D E-M5 Mark III
Olympus OM-D E-M5 Mark III currently going for $1200 USD.

Near the top, the E-M1 series has seen one revision since its launch. The E-M1 Mark II
Olympus OM-D E-M1 Mark II is a professional-grade mirrorless with a sturdy weatherproof and freezeproof body that features a large 0.74X magnification EVF. It introduced an extremely fast sensor paired with a highly capable processor that lets it capture full-resolution images at 60 FPS and even maintain 18 FPS with Continuous AF. The flagship E-M1X
Olympus OM-D E-M1X is built around the same sensor technology with dual processors in a huge body that features dual-grips, each having dual control-dials, dual joysticks, dual batteries and the best image-stabilization around, effective to 7-stops which requires compensation for the rotation of the Earth is is possible thanks to a built-in GPS and Digital Compass.

Panasonic Micro Four-Thirds Series

Panasonic Micro Four-Thirds mirrorless digital cameras are divided into families. They recently repositioned some models which makes the entire historical lineup confusion. Looking at current models, there are 3 series:

• G: The first mirrorless series is evolving towards the high-end as technological advancements allow more features to be packed into their miniature-DSLR-style body. All G-series cameras offer a built in EVF with Eye-Start Sensor and dual control-dials. Models launched after the G7
  Panasonic Lumix DMC-G7 all include built-in image-stabilization in a weatherproof body. The Panasonic Lumix G9
  Panasonic Lumix G9 is now the flagship Micro Four-Thirds mirrorless, offering triple control-dials and high-speed sensor capable of 60 FPS or 20 FPS with Continuous AF.
• GH: This series prioritizes performance and extensive features for video, some unique among stills cameras. All GH series can record Cinema 4K video with external audio input and output, plus time-code. GH-series cameras are relatively large for mirrorless, while offering rare triple control-dials and a large built in EVF in a weatherproof body. The GH5s
  Panasonic Lumix GH5s is unique in that it uses a larger sensor which gets cropped to the same 2X FLM at different aspect-ratio to maintain a constant diagonal field-of-view, although its larger sensor prevents the camera from offering IBIS.
• GX: Actually a family for 3 series split by the number of digits in the model number. The GX850
  Panasonic Lumix GX850 is the smallest mirrorless. This entry-level unit only has one control-dial and lacks image-stabilization and an EVF, with no provision to add one. The mid-level GX85
  Panasonic Lumix DMC-GX85 remains very compact while adding an EVF, image-stabilization and second control-dial. The upper-class GX9 reviewed here
  Panasonic Lumix DC-GX9 improves further with a Tiling EVF and more advanced sensor and superior processing power. Note that the GX9 is not weatherproof like the GX8
  Panasonic Lumix DMC-GX8 it replaces yet manages to be considerably smaller and lighter.

Micro Four-Thirds Lenses

There is a huge number of Micro Four-Thirds lenses available. Together Panasonic and Olympus make almost ¾ of these. Rectilinear lenses cover a focal-range from 7 to 400mm. Plus, there are a few fisheye lenses, including a 4mm Circular
Venus Optics Laowa 4mm F/2.8 Circular Fisheye that renders a 210° field-of-view. The majority of these lenses are small and light, making Micro Four-Thirds the most compact mirrorless system that is still in production.

The lineup includes nearly every type of lens: constant aperture zooms, light zooms, high zooms, bright primes, small primes and macro lenses. Panasonic and Olympus lenses may be used interchangeably on cameras of either brand. Panasonic makes the only 3D lens, making Micro Four-Thirds the only 3D-capable mirrorless system. This lens projects two views of the scene which must be merged into a 3D image in software.

Micro Four-Thirds and Sony E have the most support from third-party lens manufacturers. Irix, Panasonic, Samyang, Sigma, Tamron, Tokina, Venus Optics, Zuiko, ZY Optics all make native Micro Four-Thirds lenses. Some of these third party only produce manual lenses, as they do for other mounts too. Micro Four-Thirds cameras are compatible with Four-Thirds lenses, including weather-sealed ones using a weather-sealed mount-adapter. All Four-Thirds lenses are fully functional when used on a Micro Four-Thirds camera with the right adapter.