Micro Four Thirds system

The Micro Four Thirds system (MFT) is a standard created by Olympus and Panasonic, and announced on August 5, 2008, for the design and development of mirrorless interchangeable lens digital cameras and camcorders. In 2014, JK Imaging Ltd., which currently holds the Kodak brand, released its first Micro Four Thirds camera, the Kodak Pixpro S-1.

MFT shares the original image sensor size and specification with the Four Thirds system, designed for DSLRs. Unlike Four Thirds, the MFT system design specification does not provide space for a mirror box and a pentaprism, allowing smaller bodies to be designed, and a shorter flange focal distance and hence smaller lenses to be designed. Virtually any lens can be used on MFT camera bodies, as long as an adapter exists. For instance, Four Third lenses can be used with auto focus using the adapters designed by Olympus and Panasonic.

Sensor size and aspect ratioh2>

The image sensor of Four Thirds and MFT is commonly referred to as a 4/3" type or 4/3 type sensor (inch-based sizing system is derived from now obsolete video camera tubes). The sensor measures 18 mm × 13.5 mm (22.5 mm diagonal), with an imaging area of 17.3 mm × 13.0 mm (21.6 mm diagonal), comparable to the frame size of 110 film. Its area, ca. 220 mm², is approximately 30% less than the APS-C sensors used in other manufacturers' DSLRs, yet is around 9 times larger than the 1/2.5" sensors typically used in compact digital cameras.

The Four Thirds system uses a 4:3 image aspect ratio, in common with other compact digital cameras but unlike APS-C or full-frame DSLRs which usually adhere to the 3:2 aspect ratio of the traditional 35 mm format. Thus the "Four Thirds" refers to both the size of the image and the aspect ratio of the sensor. Note that actual size of the chip is considerably less than 4/3 of an inch, the length of the diagonal being only 22.5 mm. The 4/3 inch designation for this size of sensor dates back to the 1950s and vidicon tubes, when the external diameter of the camera tube was measured, not the active area.

The MFT design standard also calls for being able to record multiple formats, 4:3, 3:2 (traditional DSLR formats which have origins with 35 mm film still cameras), 16:9 (the native HD video format specification), and 1:1 (a square format). With the exception of two MFT cameras, all MFT cameras record in a native 4:3 format image aspect ratio, and through cropping of the 4:3 image, can record in 16:9, 3:2 and 1:1 formats. This multiple recording format flexibility is a MFT system design standard, which also incorporates seamless integration of HD video recording in the same camera body.

The 2009 introduction of the Panasonic Lumix DMC-GH1 camera extends the 4:3 format image aspect ratio recording capabilities to native 16:9 and 3:2 image aspect ratio formats, rather than crops of a native 4:3 image. The GH1 uses a bigger sensor matrix that uses the full diagonal of the image circle in all three formats. This is called multi-aspect capability. To date, the multi-aspect sensor is common only to the Panasonic GH1 and its successor the Panasonic Lumix DMC-GH2.

In addition, all current Micro Four Thirds cameras have sensor dust removal technologies, but this is not exclusive to the format.

Lens mount

The MFT system design specifies a new bayonet type lens mount with a flange focal distance of slightly under 20 mm â€" half as deep as the Four Thirds system design. By avoiding internal mirrors the MFT standard allows a much thinner camera body. Viewing is achieved on all models by live view electronic displays with LCD screens. In addition some models feature a built-in electronic viewfinder (EVF) while others may offer optional detachable electronic viewfinders, or even as an option an independent optical viewfinder typically matched to a particular non-zoom prime lens. The flange diameter is about 38 mm, 6 mm less than that of the Four Thirds system. Electrically, MFT uses an 11-contact connector between lens and camera, adding to the nine contacts in the Four Thirds system design specification. Olympus claims full backward compatibility for many of its existing Four Thirds lenses on MFT bodies, using a purpose built adapter with both mechanical and electrical interfaces (though when using FT lenses, the speed of the autofocus may be slower in certain conditions than when using dedicated Four Thirds body, because of differences in type of the AF system).

The shallow but wide MFT lens mount also allows the use of existing lenses including Leica M, Leica R, and Olympus OM system lenses, via Panasonic and Olympus adapters. Aftermarket adapters include Leica Screw Mount, Contax G, Canon, Nikon, and Pentax, among others. In fact, almost any still camera, movie or video camera interchangeable lens that has a flange focal distance greater than or marginally less than 20 mm can often be used on MFT bodies via an adapter. While these so-called "legacy" lenses can only be used in a manual focus, manual aperture control mode on MFT cameras, hundreds of lenses are available for use, even those that survive for cameras no longer in production.

Autofocus design

The MFT system design specifies the use of contrast-detection autofocus (CDAF) which is a common autofocus system for compact or "point-and-shoot". By comparison, virtually all DSLRs use a different autofocus system known as phase-detection autofocus (PDAF). The use of separate PDAF sensors has long been favored in DSLR systems because of mirror box and pentaprism design, along with better performance for fast-moving subjects.

The (non-Micro) Four Thirds system design standard specifies a 40 mm flange focal length distance, which allowed for using a single lens reflex design, with mirror box and pentaprism. Four Thirds DSLR cameras designed by Olympus and Panasonic initially used exclusively PDAF focusing systems. Olympus then introduced the first live view DSLR camera, which incorporated both traditional DSLR phase focus and also optional contrast detection focus. As a result, newer Four Thirds system lenses were designed both for PDAF and contrast focus. Several of the latter Four Thirds lenses focus on Micro Four Thirds proficiently when an electrically compatible adapter is used on the Olympus and the later Panasonic Micro Four Thirds cameras, and they focus on Micro Four Thirds cameras much quicker than earlier generation Four Thirds lenses can.

At the announcement of the MFT system design standard it was suggested that the powerful focusing motors required for contrast-detection autofocus by compact cameras and MFT may not operate properly on at least some of the existing Four Thirds lenses designed for phase-detection autofocus.

Many PDAF Four Thirds system lenses, when using adapters with proper electrical connections on Micro Four Thirds cameras, do focus much more slowly than "native" designed MFT lenses. Some Four Thirds bodies do not focus as quickly as others, or as accurately as does contrast focus. This is a downside of phase focus, which can shift focus to the front or behind the calculated focus position for each lens. Micro Four Thirds will also focus Four Thirds lenses faster than a Four Thirds camera focuses using the Four Thirds "Live View" focus. Most Four Thirds lenses still work on Micro Four Thirds, and the relative speed will depend on the camera model and the lenses used. Overall, native Micro Four Thirds lenses focus much faster than the majority of Four Thirds lenses.

An advantage to the newly introduced MFT system designed cameras is the already-existing family of very high quality, large aperture, automatic exposure, autofocusing, and sometimes even optical image stabilized Four Thirds lenses made by Olympus, Panasonic and Leica.

The current range of Olympus Pen cameras (the E-P5, the smaller E-PL5 and its less expensive "mini" version E-PM2) are claimed to be the fastest focusing removable lens cameras, including those which use phase technology (DSLR cameras). Comparative tests and the basis for all the speed improvements and whether the technology can track like a phase focus designed for sport applications are not yet known.

Comparison with other systems

For comparison of the original Four Thirds with competing DSLR system see Four Thirds system#Advantages, disadvantages and other considerations

In comparison with most digital compact cameras and many Bridge cameras, Micro Four Thirds cameras possess larger sensors which may offer better image quality, and interchangeable lenses. Some lenses feature wider apertures than those available on many compacts, allowing more control over depth-of-field and yielding greater creative possibilities. However, Micro Four Thirds cameras also tend to be larger, heavier and more expensive than compact cameras.

In comparison with most digital SLRs, Micro Four Thirds cameras are smaller and lighter. However, they also have smaller sensors (and therefore may have inferior image quality, especially in low light conditions), and often lack features such as viewfinders and built-in flash units. Micro Four Thirds cameras sometimes afford greater depth-of-field than SLRs depending on the lens used. They are not necessarily less expensive than SLRs.

The much shorter flange focal distance enabled by the removal of the mirror allows normal and wideangle lenses to be made significantly smaller because they do not have to use strongly retrofocal designs.

The Four Thirds sensor format used in MFT cameras is equivalent to a 2.0 crop factor when compared to a 35 mm film camera. This means that the field of view of a MFT lens is the same as a Full Frame lens with twice the focal length. Practically speaking, this means that a 50 mm lens on a MFT body would have a field of view equivalent to a 100 mm lens on a full frame camera. Said another way, normal lenses on MFT cameras would be only 25 mm. For this reason, MFT lenses can be smaller and lighter because to achieve the equivalent 35 mm film camera field of view, the MFT focal length is much shorter. See the table of lenses below to understand the differences better. Typical DSLR sensors such as Canon's APS-C sensors, have a crop factor of 1.6, compared to full frame's (35 mm) 1.0, and Four Thirds 2.0.

Advantages of Micro Four Thirds over DSLR cameras

Micro Four Thirds has several advantages over larger format cameras and lenses:

• Smaller and lighter
• The shorter flange focal distance means that most manual lenses can be adapted for use, though C-mount lenses have a slightly shorter flange focal distance and are trickier to adapt.
• The shorter flange focal distance may also allow for smaller, lighter and lower cost lenses. This is especially true for wide angle lenses: Compare the Olympus 4/3 7â€"14mm f/4 zoom (approximately $1800), with the lumix micro 4/3 7â€"14mm F/4 lens (approximately $800).
• Forward or back focus does not occur with contrast focus like it can when using DSLR phase focus, and likewise each lens does not have to be individually calibrated to each camera, which can be required for DSLRs to have accurate focus.
• The absence of a mirror eliminates the need for an additional precision assembly, along with its "mirror slap" noise and resultant camera vibration/movement.
• Viewfinders can be used when filming videos.
• In continuous mode (video takes or sequential shots) the smaller sensor can be cooled better to avoid the increase of image noise.
• The autofocus performance is the same for stills and videos, so the speed is much faster than conventional DSLRs in video mode.
• Because of the reduced sensor-flange distance, the sensor is easier to clean than with a DSLR, which also have delicate mirror mechanisms attached.
• The smaller sensor size may allow for smaller and lighter telephoto-lens equivalents.
• The smaller flange distance, which is 20 mm, allows for easier manufacturing of wide, fast, and telephoto lenses, as well as the option to adapt nearly any photographic and cine lens ever made.
• Smaller and lighter cameras and lenses allow discretion and portability.
• The smaller sensor size gives deeper depth-of-field for the same equivalent field of view and aperture. This can be desirable in some situations, such as landscape and macro shooting.

Advantages of the electronic viewfinder

Though many DSLRs also have "live view" functionality, these function relatively poorly compared to a Micro Four Thirds electronic viewfinder (EVF), which has the following advantages:

• Real-time preview of exposure, white balance, and tone.
• Can show a low-light scene brighter than it is.
• The viewfinder can zoom into one's preview, which a mirror-based viewfinder cannot do. This is why using manual focus through a zoomed EVF will get much a more precise result than using manual focus through a mirror.
• The viewfinder displays how the sensor will see one's potential picture, rather than an optical view, which may differ.
• The view can appear larger than some optical viewfinders, which often have a tunnel-like view.
• Not reliant on a moving mirror and shutter, which otherwise adds noise, weight, design complexity, and cost.
• No weight or size penalty for better quality of materials and design. Optical viewfinder quality varies greatly across all DSLRs.

Olympus and Panasonic approached the implementation of electronic viewfinders in two ways: the built-in EVF, and the optional hotshoe add-on EVF.

Until the introduction of the OM-D E-M5 in February, 2012, none of the Olympus designs included a built-in EVF. Olympus has four available add-on hotshoe viewfinders. The Olympus VF-1 is an optical viewfinder with an angle of view of 65 degrees, equivalent to the 17mm pancake lens field of view, and was designed primarily for the EP-1. Olympus has since introduced the high resolution VF-2 EVF, and a newer, less expensive, slightly lower resolution VF-3 for use in all its MFT cameras after the Olympus EP-1. These EVF's not only slip into the accessory hotshoe, but also plug into a dedicated proprietary port for power and communication with Olympus cameras only. Both the VF-2 and VF-3 may also be used on high-end Olympus compact point and shoot cameras such as the Olympus XZ-1. Olympus announced the VF-4 in May, 2013, along with the fourth generation PEN flagship, the E-P5.

As of mid-2011, Panasonic G and GH series cameras have built in EVF's, while two of the three GF models are able to use the add-on LVF1 hotshoe EVF. The LVF1 must also plug into a proprietary port built into the camera for power and communication. This proprietary port and the accessory is omitted in the Panasonic Lumix DMC-GF3 design. Similar to Olympus, the LVF1 is usable on high-end Panasonic compact point and shoot cameras, such as the Panasonic Lumix DMC-LX5.

Disadvantages of Micro Four Thirds compared to DSLRs

• The sensor is 40% smaller in area (2.0x crop factor) than APS-C (1.5x crop factor, or 1.6x for Canon-APS-C) sized sensors and 75% smaller (i.e. a quarter of the area) than a full frame sensor (1.0x crop factor) (35 mm equivalent), which can mean lower image quality when all other variables are the same. This might include poorer color transitions and more noise at equivalent ISO settings, especially in low light, when compared with the larger sensors.
• Contrast detect autofocus systems such as those used in Micro Four Thirds cameras were initially slower than the phase detect systems used in advanced DSLRs. This gap was eliminated with the Olympus OM-D E-M5 when shooting static subjects. The tracking of subjects moving towards or away from the camera is also difficult with contrast detection, however, this issue was eliminated in 2013 with the introduction of the Olympus OM-D E-M1's hybrid phase detection auto-focus system.
• Due to the absence of a mirror and prism mechanism, there is no ability to use a through-the-lens optical viewfinder. A through-the-lens electronic viewfinder, an attachable not-through-the-lens optical viewfinder (similar to a rangefinder or TLR), or the universally supplied LCD screen must be used instead.
• Theoretically, changing lenses can expose the sensor to more dust in a "mirrorless" camera design, compared to DSLRs that have both a mirror and a closed shutter protecting the sensor. Mirrorless cameras have dust-removal systems which attempt to minimize the impact of this problem and in practice they experience fewer dust problems than a DSLR. Many micro-four third users report never having found dust on the sensor at all.
• A larger crop factor (2x multiplier versus APS-C's 1.5x) means greater depth-of-field for the same equivalent field of view and f/stop when compared with APS-C and especially full frame cameras. This can be a disadvantage when a photographer wants to blur a background, such as when shooting portraits. This problem is somewhat mitigated by the availability of relatively inexpensive, fast, high quality prime lenses, preferred also for their compact size and light weight.
• Some Micro Four Thirds cameras are smaller than DSLRs or larger body cameras, and this can result in relatively poor ergonomics. This applies especially to handling, the depth of the right-hand grip, and the size and placement of buttons and dials.
• Micro Four Thirds lenses cannot be used on 35mm equivalent and APS-C cameras due to lens vignetting.

Advantages of Micro Four Thirds over compact digital cameras

• Greatly increased sensor size (5â€"9 times larger area) gives much better image quality, e.g. low light performance and greater dynamic range, with reduced noise.
• Interchangeable lenses allow more optical choices including niche, legacy, and future lenses.
• Shallower depth of field possible (e.g. for portraits).

Disadvantages of Micro Four Thirds compared to compact digital cameras

• Increased physical size (camera and lenses are both larger due to increased sensor size);
• Extreme zoom lenses available on compacts (such as 10×-30× models) are more expensive or simply not available on large sensor cameras due to physical size, cost, and practicality considerations;
• Similarly, larger sensors and shallow depth-of-field make bundled macro capability and close focusing more difficult, often requiring separate, specialized lenses.
• Higher cost.

Popularity with Adapted/Legacy Lenses

• Due to the short native flange distance, of the Micro Four Thirds System, the usage of adapted lenses from practically all formats has become widely popular.
• Because lenses can be used from old and abandoned camera systems, adapted lenses typically represent good value for the money.
• Adapters ranging from low to high quality are readily available for purchase online. Canon FD, Nikon F (G lenses require special adapters), MD/MC, Leica M, M42 Screw Mount, and C-mount Cine lenses to name a few are all easily adaptable to the Micro Four Thirds system with a glassless adapters resulting in no induced loss of light or sharpness.
• Due to the 2x crop factor of the Micro Four Thirds System however, most adapted glass from the 35mm film era and current DSLR lineups provide effective fields of view varying from normal to extreme telephoto. Wide angles are generally not practical for adapted use from both an image quality and value point of view.
• Using older adapted lenses on micro four thirds sometimes leads to a slight losses in image quality. This is the result of placing high resolution demands on the center crop of decade old 35mm lenses. Therefore 100% crops from the lenses do not usually represent the same level of pixel-level sharpness as they would on their native formats.
• Another slight disadvantage of using adapted lenses can be size. By using a 35mm film lens, one would be using a lens that casts an image circle that is far larger than what is required by Micro Four Thirds Sensors.
• The main disadavantage of using adapted lenses however, is that focus is manual even with natively autofocus lenses. Full metering functionality is maintained however, as are some automated shooting modes (aperture priority).
• A further disadvantage shared with all systems that do not conform to the internal dimensions of the Leica mount specification is that some LM and LTM lenses with significant rear protrusions simply will not fit inside the camera body and risk damaging lens or body - an example is the biogon type of lens.
• A possible advantage for wildlife shooters and birders in particular lies with the fact that system's 2x crop factor means that old 35mm telephoto lenses possess the same crop factor as extreme telephotos. This does not, however, mean that the lenses' focal length is doubled or that the magnification power increases: a 200mm zoom lens for 35mm does not become a 400mm zoom lens when used with Micro Four-Thirds; rather, the crop factor for the 200mm lens when used with Micro Four-Thirds is the same as that of a 400mm lens.
• Overall, the ability to use adapted lenses gives Micro Four Thirds a great advantage in overall versatility and the practice has gained a somewhat cult following. Image samples can be found readily online, and in particular on the MU-43 adapted lenses forum.

Micro Four Thirds system cameras

As of Jun 2012, Olympus, Panasonic, Cosina/Voigtländer, Carl Zeiss AG, Jos. Schneider Optische Werke GmbH, Komamura Corporation, Sigma Corporation, Tamron, Astrodesign, Yasuhara, and Blackmagic Design have a commitment to the Micro Four Thirds system.

The first Micro Four Thirds system camera was Panasonic Lumix DMC-G1, which was launched in Japan in October 2008. In April 2009, Panasonic Lumix DMC-GH1 with HD video recording added to it.

The first Olympus model, Olympus PEN E-P1 was shipped in July 2009. In January 2014, JK Imaging Ltd. launched its Kodak-branded model S-1.

In August 2013 SVS Vistek GmbH in Seefeld, Germany introduced the first high-speed industrial MFT lens mount camera using 4/3" sensors from Truesense Imaging, Inc (formally Kodak sensors), now part of ON Semiconductor. Their Evo "Tracer" cameras range from 1 megapixels at 147 frames per second (fps) to 8 megapixels at 22 fps.

Micro Four Thirds lenses

A promise of the Micro Four Thirds standard is reduced lens size and weight. The reduced flange focal distance of Micro Four Thirds enables most lenses to be made significantly smaller and cheaper than for a traditional DSLR, because the retrofocus optical schemes can be avoided or made less extreme. Of particular interest in illustrating this fact are the Panasonic 7-14mm ultra-wideangle (equivalent to 14â€"28 mm in the 35mm film format) and the Olympus M.Zuiko Digital ED 9-18mm ultra wide-angle lens (equivalent to an 18â€"36 mm zoom lens in the 35mm film format). On the telephoto end, the Panasonic 100-300mm and Olympus 75-300mm zooms show how small and light extreme telephotos can be made. The 300 mm focal length in Micro Four Thirds is equivalent to 600 mm focal length in more traditional full frame cameras.

When compared to a full frame camera lens providing a similar angle of view, rather than weighing a few kilograms (several pounds) and generally having an length of over 60 cm (2 ft) end to end, the optically stabilized Panasonic LUMIX G VARIO 100-300mm lens weighs just 520 grams (18.3 oz), is only 126 mm (5.0 in) long, and uses a relatively petite 67 mm filter size. As a point of comparison, the Nikon 600mm f5.6 telephoto weighs 3600 grams (7.9 lb), is 516.5 mm (20.3 in) in length and uses a custom 122 mm filter.

Further, both Panasonic and Olympus manufacture an adapter to enable use of any Four Thirds lenses on Micro Four Thirds cameras. While many Four Thirds lenses accept firmware updates to enable contrast autofocusing, some are slow to autofocus, and some others are manual-focus-only.

Image Stabilization - Different approaches

Olympus and Panasonic approach image stabilization (IS) differently. Olympus uses sensor-shift image stabilization, which it calls IBIS (In-Body Image Stabilization). IBIS stabilizes the image by shifting of the entire sensor. Panasonic uses lens-based stabilization, which it calls MEGA OIS. MEGA OIS stabilizes the image by shifting a small optical block within the lens. In August 2013 Panasonic also introduced a camera (Lumix DMC-GX7) featuring a built-in IBIS.

Panasonic claims that OIS is more accurate because the stabilization system can be designed for the particular optical characteristics of each lens. A disadvantage of this approach is that the OIS motor and shift mechanism must be built into each lens, making each lens physically larger, heavier and more expensive than a comparable non-OIS lens. As of mid-2011, of the available and announced Panasonic lenses, the 8 mm fisheye, 7â€"14 mm wide angle zoom, 14 mm prime, and 20 mm prime are not image stabilized.

Whilst none of the Olympus lenses have built-in IS, all Olympus Micro Four Thirds cameras have in-camera IS, and therefore all Olympus M.Zuiko Digital lenses benefit from the camera's stabilization system. The advantage with Olympus' in-body IS is that Olympus lenses are smaller and lighter than comparable Panasonic lenses, and even vintage manual focus lenses can make use of the in-body stabilization when used with an appropriate mount adapter. This latter fact has added to interest in Micro Four Thirds cameras by many hobbyists, especially amongst users of traditional Leica or Voigtlander rangefinder cameras. Olympus introduced in 2012 a new leap forward IBIS technology: Olympus "5 Axis" IBIS system, initially only available on "OM-D" generation Olympus cameras.

Lens compactness and mount adaptability

Since most Micro-Four-Thirds lenses have neither a mechanical focussing ring nor an aperture ring, adapting these lenses for use with other camera mounts will be impossible or compromised. A variety of companies manufacture adapters to use lenses from nearly any legacy lens mount (such lenses, of course, support no automatic functions.) For the Four Third lenses that can be mounted on MFT bodies, see Four Thirds system lenses. For the Four Third lenses that support AF, see. For those that support fast AF (Imager AF), see.

As of November 2013, the following Micro Four Thirds system lenses, which can be used by all MFT camera bodies, except as noted, have been released or announced with availability within 3 months of announcement:

Zoom lenses

Wide zoom lenses

Standard zoom lenses

Telephoto zoom lenses

Superzoom lenses

Fixed focal length lenses

On Jan 9, 2012 Sigma announced its first two lenses for Micro Four Thirds, the "30mm F2.8 EX DN and the 19mm F2.8 EX DN lenses in Micro Four Thirds mounts". In a press release posted on January 26, 2012, Olympus and Panasonic jointly announced that "ASTRODESIGN, Inc., Kenko Tokina Co., Ltd. and Tamron Co., Ltd. join[ed] the Micro Four Thirds System Standard Group". On January 26, 2012, Tokina and Tamron have indicated they would be designing lenses for the Micro 4/3 system as well.

Prime lenses with Autofocus

Prime Lenses without Autofocus

Macro lenses

Fisheyes

3D lenses

• Panasonic Lumix G 12.5mm 3D lens f/12 (35mm EFL = 65mm) when using 16:9 format on Panasonic Lumix DMC-GH2. This lens is only compatible with newer Panasonic bodies and the Olympus OMD E-M5. Not compatible with Panasonic Lumix DMC G-1, GF-1 and GH-1. Not compatible with any Olympus PEN digital cameras.

Digiscoping lenses

• SLR Magic 12-36x50 ED spotting scope for micro four thirds f/8-25 (announced September 2011)(35mm EFL = 840-2520mm)

Pinhole

• SLR Magic x Toy Lens Pinhole f/128 'lens' cap (announced March 2012)(35mm EFL = 12mm)
• Wanderlust Pinwide f/96 - f/128 'lens' cap

3D

July 27, 2010 Panasonic has announced the development of a 3-dimensional optic solution for the Micro Four Thirds system. A specially designed lens allows it to capture stereo images compatible with VIERA 3D-TV-sets and Blu-ray 3D Disc Players.

See also

• Image sensor format
• Lens mount
• Lenses for SLR and DSLR cameras
• List of lens mounts
• Mirrorless interchangeable-lens camera (also referred to as "compact system camera")

Notes

References

• The Micro Four Thirds Standard official pages.

External links

Media related to Micro Four Thirds system cameras at Wikimedia Commons

• Panasonic Lumix G family of lenses
• Olympus PEN system lenses
• Cosina Voigtländer Nokton MFT mount product Page
• Noktor Hyperprime MFT mount product page
• Samyang Fisheye product page
• Reviews of the Olympus E-M1, both alone and with various mFT lenses, at FurnFeather.net.