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  • Michael Kohnhorst

All About the Micro Four Thirds Format

An illustration of the official Micro Four Thirds logo.
Official Micro Four Thirds Logo

Most of this was written before the June 24, 2020 announcement that the Olympus imaging division would be carved out of Olympus and sold to a Japanese investment fund. Like all camera manufacturers, Olympus has struggled to meet the challenge of the ubiquitous and increasingly capable cell phone camera. While there are assurances from the buyers of an appreciation for the value of “reputable brands such as OM-D and Zuiko,” at this time we can only guess at the fate of these great cameras and lenses.


As digital imaging technology matures, photographers and cinematographers are blessed with a wide array of affordable cameras with impressive stills and video capabilities. Every format has advantages and disadvantages and using a mix of objective and subjective criteria we settle on the gear we feel best suits our individual needs. For me, the Micro Four Thirds format strikes a pleasing balance — easily managed size and weight, stills/video versatility, solid image quality, and a fully developed and growing selection of compatible cameras, lenses, and accessories from numerous manufacturers.

My affinity for Micro Four Thirds — especially for video

I shot commercials and 2nd Units for episodic TV shows in the days of standard definition television as well as 2nd Units for 1.85 films before Super 35 was widely adopted. The Micro Four-Thirds sensor area is essentially the same size as the SDTV Safe Action Area on a 35mm motion picture camera and the 1.78:1 video sensor area is quite close to the 35mm film standard for 1.85:1 projection aperture. Because of these similarities, the Micro Four Thirds format feels very familiar to me, and I find it reassuring that these imaging areas were used to produce high quality professional results for many years. I used David Eubanks’s indispensable pCAM Pro app to illustrate these similarities below.

An illustrations comparing micro four thirds format to 35mm motion picture formats
Format comparisons between micro four thirds and 35mm motion picture formats.

My first Micro Four-Thirds camera was a Panasonic GH1 with a Leica 25mm f/1.4 Summilux and Lumix 14-140mm f/3.5-5.6 that I purchased in 2010. The quality was good enough for my personal work, and I fully expected the format to progress in capability as sensor, electronic viewfinder, image stabilization and other technologies continued to advance. In addition to the GH1, I’ve now owned Panasonic GX7, GX85, GH3 and GH5 and GH5S cameras as well as Micro Four Thirds lenses from five manufacturers. I’ve added a full frame Panasonic Lumix S5 camera for some of my still work, but I’ll continue to shoot some stills and all of my motion work with Micro Four Thirds cameras and lenses.

I’ve made a commitment to Micro Four Thirds where video is concerned because my projects these days tend to be smaller and don't demand the imaging horsepower of a Panasonic VariCam 35 or Arri Alexa. I mostly work with a small crew or by myself, and I like to shoot 2 cameras whenever possible. With fewer people to schlep the gear, a smaller and lighter camera package is a big plus. I’m admittedly old school about this, but for me motion pictures demand manual focus. A small crew likely means working without a dedicated focus puller on at least one of the cameras. Maintaining focus on a moving subject (sometimes with a moving camera) is a challenge in any format. In terms of depth of field, full frame cameras make the task much more difficult. I again use pCAM Pro, this time to illustrate the considerably shallower depth of field of a full frame sensor as compared to a Micro Four Thirds sensor for the same field of view and f/stop.

An illustration comparing depth of field on a Canon 5D and a Panasonic Lumix GH5S.
A Canon 5D has about half as much depth of field for the same field of view and lens aperture as a Lumix GH5S.

An illustration comparing depth of field of a Panasonic Lumix GH5S to a Canon 5D.
A GH5S has almost double the depth of field for the same field of view and lens aperture as a Canon 5D.

So long as the image size and f/stop are the same for both formats, the Micro Four Thirds format will always have approximately double the depth of field as a camera with a full frame sensor. For the image size above, a full frame camera would need to be set at 1/6 stop open from f/5.6 to achieve the same 3.1″ depth of field.

A little history — before Micro Four Thirds there was Four Thirds

Anticipating the disruption that digital technology would bring to its 35mm camera business, Olympus set out in the late 1990s to create a completely new digital format. The concept was to build a system around the smallest sensor size capable of delivering high quality images. The resulting format would allow for the design of smaller and lighter cameras and lenses, while also facilitating the development of a new line of telecentric lenses designed for use with digital sensors. In 1999 Olympus engineer Katsuhiro Takada settled upon the image area of a 4/3″ video vacuum tube as best meeting these requirements. 4/3 designates the diameter of the tube in inches and was never intended to designate aspect ratio. The image circle produced by the 4/3″ vacuum tube is 21.3mm measured diagonally within the 4:3 aspect ratio of standard definition television, yielding a frame that is 13 X 17.3mm.

From the beginning, the Four Thirds format was conceived as a non-proprietary, open standards format that would allow compatibility among equipment from many manufacturers. The early Four Thirds group included Olympus, Panasonic, Sanyo, Leica, Fujifilm and Kodak, with Kodak manufacturing the first sensors. At that time, all digital cameras with professional aspirations used reflex mirror viewing systems. The first Four Thirds Digital Single Lens Reflex camera was the Olympus E-1 which was introduced in 2003. Panasonic introduced their first DSLR, the DMC-L1, in 2006 along with a Leica 14-50mm f/2.8-3.5 zoom. Four Thirds products were well executed, but the format had vocal detractors and struggled to gain traction in the marketplace. Before the manufacture of Four Thirds gear ended in the spring of 2017, Olympus had introduced fifteen Four Thirds camera models, in three market segments, accompanied by nineteen Four Thirds lenses, also divided into three market segments. Panasonic had produced two Four Thirds cameras and, in partnership with Leica, four Four Thirds lenses.

A photograph of the Olympus E-1 and Panasonic LC1, the first Four Thirds cameras.
Olympus E-1 and Panasonic DMC-LC1

Micro Four Thirds

The Micro Four Thirds format is the direct descendant of the Four Thirds format retaining the 13 X 17.3mm sensor size. Micro 4/3 has the distinction of being the first mirrorless interchangeable lens format. Developed by Panasonic and Olympus, the Micro Four Thirds format utilized an electronic viewfinder (evf) to replace the reflex viewing system. This eliminated the prism, mirror box and the related mechanics of a reflex viewing system and allowed the flange depth (aka flange focal distance) to be reduced by roughly 50% from 38.67mm to 19.25mm. The lens mount was smaller than the Four Thirds mount and incorporated a new lens/body communication protocol. The smaller Micro 4/3 lens mount and shallow flange depth allowed the development of cameras and lenses that were smaller and lighter than their Four Thirds predecessors. Active adapters for Four-Thirds lenses and passive adapters for almost any manual SLR or motion picture lens were available almost immediately. The first Micro 4/3 camera, the Panasonic Lumix DMC-G1, was introduced in the fall of 2008. The GH1 followed in the spring of 2009. Olympus’s first Micro 4/3 offering, the Pen E-P1 arrived in July, 2009. Having two established diversified Japanese corporations building compatible cameras and lenses has worked well for users. The competition between Olympus and Panasonic has been a source of continuing innovation and improvement in imaging technology and lens design. Their differing approaches reflect the history of each organization.

A photograph of a Panasonic Lumix DMC-G1 and Olympus Pen E-P1, the first Micro Four Thirds cameras.
Panasonic Lumix DMC-G1 and Olympus Pen E-P1


Olympus has a long heritage of designing and manufacturing cameras and lenses and introduced their first camera in 1935. The 4/3 and Micro 4/3 formats may be thought of as descendants of the Yoshihisa Maitani designed Olympus Pen-F, FT and FV SLR cameras manufactured between 1963 and 1970. This line of diminutive 35mm half frame reflex cameras presented an innovative and attractive contrast to the other SLR cameras of the era. The Pen-F line produced images within a half frame measuring 18 X 24mm rather than the standard 24 X 36mm, allowing 72 exposures per roll instead of 36. A high quality set of primes, a pair of zooms and an extensive line of accessories were made to complement the Pen-F and comprised a true reflex camera system. A digital Pen-F, designed to evoke the analog version from the 1960s, was introduced in early 2016.

A photograph of the film and digital iterations of Olympus Pen-F cameras.
Film and digital versions of the Olympus Pen-F

The superb OM line of 35mm SLR cameras and lenses, manufactured from 1972 until 2002, continued the Olympus credo of “smaller is better.” The camera was originally called the Olympus M to honor designer Maitani. The O was added after complaints of trademark infringement from Leica. The current Olympus flagship, the highly rated OM-D E-M1, was introduced in the fall of 2013. This successful line continues the OM heritage and was updated with a Mark 2 version in 2016 and a Mark 3 version in 2020. Olympus also offers the PEN EP, E-M5 and E-M10 lines.

A photograph of Yoshihisa Maitani and an Olympus OM-1 and an Olympus OM-D EM1 Mark II.
Yoshihisa Maitani, 35mm Olympus OM-1 and digital Olympus OM-D EM1 Mark II

A photograph of thee cameras, Olympus PEN E-PL10, OM-D E-M5 Mark 3, and OM-D E-M10 Mark 3.
Olympus PEN E-PL10, OM-D E-M5 Mark 3, and OM-D E-M10 Mark 3

Olympus has been described as an optical company that makes cameras to mount on their great lenses. For the Micro 4/3 format Olympus began by offering a set of small and relatively fast M. Zuiko primes as a step up from their kit lenses. The M.Zuiko line consists of a 12mm f/2, 17mm f/1.8, 25mm f/1.8, 45mm f/1.8, and 75mm f/1.8. Olympus also has the fully developed PRO lens lineup, which began with the introduction of a trio of f/2.8 zooms; the 7-14mm, 12-40mm, and 40-150mm. These zooms were joined by a trio of f/1.2 primes; 17mm, 25mm, and 45mm in 2017. The PRO line has continued to expand with the addition of an 8mm f/1.8 fisheye, a 300mm f/4 telephoto, the all-in-one 12-100mm f/4 as well as 1.4X and 2X extenders. Many Olympus lenses possess a clever clutch mechanism that allows them to function as either auto-focus or true manual focus lenses making them well suited to motion work as well as stills.

A photograph of a large group of Olympus lenses.
Olympus M.Zuiko and PRO Lenses


The professional quality internal 10 bit, 4:2:2 video imagery and high frame rate capability of Panasonic’s GH5 and GH5S cameras are descended from decades of Panasonic video camera engineering and manufacture. Panasonic made one of the first VHS camcorders in 1985 and was early to HD video with their 2/3” 3-chip VariCam AJ-HDC27 Camcorder in 2001. The original VariCam was valued for its natural, film-like color rendition and high frame rate capability. Released in 2015, the VariCam 35 Super 35 motion picture camera was the first of the product line built to compete with Arriflex, Sony and Red cameras. The line continued Panasonic’s tradition of innovation, offering 4k acquisition, dual native ISOs of 800 and 5000, high frame rates, and available RAW recording via a Codex workflow. In 2017 Panasonic introduced the EVA-1, a Super 35 VariCam spinoff designed to compete with the SONY FS7. The EVA-1 dashed the hopes of those waiting for a professional level M43 motion camera to succeed the inadequate AG-AF100 from late 2010. The fixed lens AG-DVX200, introduced in 2015, is the only camera with a M43 sized sensor in Panasonic’s professional video lineup.

A photograph of two Panasonic cameras, an AJ-HDC27 VariCam and VariCam 35.
AJ-HDC27 VariCam and VariCam 35

Similar to Olympus, Panasonic’s Micro 4/3 cameras have developed within several product lines defined by purpose and price point. The flagship GH hybrid cameras are aimed primarily at cinematography, but are also capable stills cameras. Panasonic recognized the potential of the GH line when their users began hacking the firmware of the 16 megapixel GH2 camera to record video at higher bit rates. The GH3, released in December, 2012, was very well received and capable of a then astonishing bit rate 96mb/sec. It also featured the first built-in intervalometer for time lapse. The GH4, released a year and a half later, introduced 4K acquisition, focus peaking, and more slow motion frame rates. The March, 2017, release of the 20.3 megapixel GH5 set new standards for mirrorless video with the addition of 10 bit 4:2:2 internal recording and a very effective iteration of in-body image stabilization. This was followed by the GH5S in January, 2018. With approximately 1/2 as many pixels, the non-stabilized fixed 10.2 megapixel GH5S sensor has larger light gathering photo sites and features dual ISO (400 & 2500) technology borrowed from the VariCam 35. This greatly facilitates shooting at low light levels while the larger physical size of the sensor allow it to use the full image circle in all aspect ratios yielding a larger 1.78:1 image area. Panasonic’s G and GX lines are aimed primarily at stills shooters, with the GX line emulating a rangefinder style camera.

A photograph of two cameras, a Panasonic Lumix DMC-GH1 and DC-GH5.
Panasonic Lumix DMC-GH1 and DC-GH5

A photograph of two cameras, a Panasonic Lumix DC-G9 and DC-GX9.
Panasonic Lumix DC-G9 and DC-GX9

Through a long standing relationship with Leica, Panasonic has built a formidable group of high quality M43 lenses — 12mm f/1.4 Summilux, 15mm f/1.7 Summilux, 25mm f/1.4 Summilux, 42.5mm f/1.2 Nocticron, 45mm f/2.8 Macro-Elmar, 200mm f/2.8 Elmarit, 8-18mm f/2.8-4 Vario-Elmarit, 12-60mm f/2.8-4 Vario-Elmarit, 100-400 f/4-6.3 Vario Elmar, and the recently introduced 10-25mm f/1.7 Vario-Summilux. There is also the Lumix line of primes and zooms built around the second generation of the highly regarded 12-35mm f/2.8 and the 35-100mm f/2.8 zooms.

A photograph of a large group of Panasonic Leica and Panasonic Lumix lenses.
Panasonic Leica and Lumix Lenses

M43 Optics

In addition to Olympus and Panasonic, lens manufacturers that have developed lenses that conform to the M43 standard include Sigma, Kowa, Tokina, Meike, Laowa, DZO, and Voigtlander. The shallow flange depth allows adapters to mount just about any legacy lens to a Micro 4/3 camera. Matabones and other imaging reduction adapters have optical elements and adapt full frame and Super 35 lenses to M43 cameras projecting a reduced and brighter image onto the sensor.

A photograph of two groups of lenses, the Meike Cine Style Lenses and Voigtlander Noktons.
Meike Cine Style Lenses and Voigtlander Noktons

A photograph of three Sigma lenses.
Sigma 16mm f/1.4, Sigma 30mm f/1.4, and Sigma 56mm f/1.4

A photograph of three Kowa lenses.
Kowa 8.5mm f/2.8, 12mm f/1.8, and 25mm f/1.8 Prominar Lenses

A photograph of two DZO zoom lenses.
DZO Parfocal 10-24mm T/2.9 and 20-70mm T/2.9 Manual Zooms

A photograph showing front and back views of a Metabones optical reduction lens adapter.
Metabones Contax/Yashica to Micro Four-Thirds Reducing Apapter

Anamorphic M43 Optics

A distinct advantage of working in a format with a 4:3 aspect ratio is the ability to use 2X anamorphic lenses. The anamorphic process squeezes the image in the horizontal axis. When it is unsqueezed in post processing the image is roughly twice as wide as it is tall, using optics to essentially double the sensor’s image area while yielding a quintessentially cinematic widescreen aspect ratio. To aid in composition, Panasonic’s GH5 and GH5S have the ability to “unsqueeze” the anamorphic image in the viewfinder. The SLR Magic 2X Anamorphot line deliver a 2.66:1 aspect ratio, and the Vazen 1.8X anamorphic line delivers the more standard 2.40:1 aspect ratio. Previously used almost exclusively for feature length motion picture production, the 2X anamorphic process is now accessible to M43 users at a relatively low price point.

A photograph showing two groups of Micro Four Thirds anamorphic lenses.
SLR Magic 2X Anamorphot and Vazen 1.8X Anamorphic

Strictly Motion

Blackmagic Design

In 2012 Blackmagic Design, an Australian company known for its motion picture post-production software and hardware, entered the production side of things with the Blackmagic Cinema Camera. It was available with a Canon EF mount or a passive M43 mount. The BMCC’s sensor area was smaller than the Micro 4/3 standard, measuring 8.8mm x 15.6mm. The BMCC gained notice for its ability to record in RAW, Apple ProRes, CinemaDNG and Avid DNxHD formats. The camera came bundled with Blackmagic’s industry-standard color correction/editing software, DaVinci Resolve.

A photograph of the BlackMagic Cinema Camera.
BlackMagic Cinema Camera

The diminutive Blackmagic Pocket Cinema Camera, also bundled with DaVinci Resolve, followed in 2013. It had an active Micro 4/3 mount and a 7.02 x 12.48mm Super 16 sensor. Recording RAW files with this tiny package is still a remarkable accomplishment. In 2014 the Blackmagic Micro Cinema Camera was introduced. It has an active Micro 4/3 mount and a 7.02X12.48mm Super 16 size sensor. The tiny BMMCC was aimed squarely at drone and gimbal use.

A photograph of the BlackMagic Pocket Cinema Camera and 2 views of the BlackMagic Micro Cinema Camera.
BlackMagic Pocket Cinema Camera and 2 views of the BlackMagic Micro Cinema Camera

The Micro Studio 4k can be set up for remote operation and the Studio Camera 4k has a 10 inch monitor and connections and comm channels. Both also use the 7.02 x 12.48mm Super 16 sensor.

A photograph with 2 Views of the BlackMagic Micro Studio 4K and one shot of the BlackMagic Studio Camera 2 4K.
2 Views of the BlackMagic Micro Studio 4Kand the BlackMagic Studio Camera 2 4K

In 2018 Blackmagic introduced the Pocket Cinema Camera 4K with a 10 x 18.96mm sensor, redesigned body, 5″ monitor, numerous other improvements and a $1300 price tag.

A photograph of the BlackMagic Pocket Cinema 4K camera.
BlackMagic Pocket Cinema 4K

Z Cam

This Chinese camera maker is intent on shaking things up. Their first camera, the Z Cam E1, was a kickstarter funded M43 video camera that debuted in 2015. It resembled a large GoPro and had limited capability and a small price tag. The Z Cam E2 MFT debuted at NAB 2018. It was a big improvement over the E1 with a larger body, built in 10 bit 4:2:2 ProRes recording, an iOS monitor/camera control app, and additional codecs and frame rates. Z Cam continues to make improvements to the E2 and at NAB 2019 they announced Super 35 and Full Frame cameras boasting 6K and 8K resolution. All of Z Cam’s offerings are aggressively priced with the Micro 4/3 E2 going for $2000, and the more basic E2C (homage to Arri 2C?) priced at an astonishing $800.

A photo of two camera, the Z Cam E2 and Z Cam E2C.
Z Cam E2 and Z Cam E2C

Closing Thoughts

For some odd reason, there are people who relish predicting the demise of the Micro Four Thirds format. With the admittedly unsettling news we heard recently from Olympus, these predictions are again in vogue. What I think these Nostradamus types miss is the value/video image quality proposition Micro 4/3 represents for users and the importance of Micro 4/3 being a non-proprietary, open format. Because of this, Micro Four Thirds provides a way in to a well established format with a substantial user base for camera makers such as BlackMagic and Z Cam and lens makers such as Meike and DZO. Voigtlander recently added their 6th Micro 4/3 Nokton lens and there is also the essentially untapped potential for the 2X anamorphic process that has caused lens makers Vazen and SLR Magic to embrace the M43 format. Adding cameras and lenses from these newer Micro 4/3 manufacturers to the substantial product lines from Panasonic and Olympus presents photographers and cinematographers with the widest array of compatible equipment available for any format.

The quality of a 13 x 17.3mm M43 image will never objectively match the quality from a larger sensor, but a skilled photographer or cinematographer can achieve great results using Micro 4/3 gear — especially when so much of our work will only be viewed online. A test drive of the the Leica 42.5mm f/1.2 Nocticron, Voigtlander 42.5mm f/.95 Nokton or Olympus 45mm f/1.2 PRO will verify that it is possible to throw M43 backgrounds as far out of focus as one might desire.

Here are 2 photos illustrating how M43 has fulfilled the ideal of high quality imaging in a compact package.

This a photograph of a micro four thirds camera package with 2 camera, 6 lenses, batteries, filters, and other accessories in a 20x11x7 case.

A photograph of 2 cameras , 2 lenses in a small shoulder bag.

Unless otherwise noted all photo copyright held by respective manufacturer.


David Eubank’s indispensable cinematography and photography tool: pCAM Pro

Micro Four-Thirds February, 2020, lens catalog:

Official 4/3 & Micro 4/3 site:

Olympus Cameras and Lenses:

Vazen Anamorphic Lenses:



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