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 mirrorless interchangeable lens digital cameras and camcorders design and development.
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 using the proper adapter. For instance, Four Third lenses can be used with auto focus using the adapters designed by Olympus and Panasonic.

Sensor size and aspect ratio
 Drawing showing the relative sizes of sensors used in most current digital cameras, relative to a 35mm film frame.
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.[3] Its area, ca. 220 mm², is approximately 40% 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 used 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 imager 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 35mm 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.

Lens mount
The MFT system design specifies a new bayonet type lens mount with a flange focal distance of slightly under 20 mm – 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 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.
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.[7] 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 DSLR 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.
The Four Thirds system design standard specifes 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 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.
It had been suggested at the announcement of the MFT system design standard that the contrast-detection autofocus used by compact cameras and MFT requires powerful focusing motors and 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 a Micro Four Thirds cameras, end up focusing much more slowly than "native" designed MFT lenses. Although some Four Thirds bodies did not focus as quickly as others, or always as accurately as does contrast focus, which 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 can focuses using the Four Thirds "Live View" focus. Most Four Thirds lenses still work on Mircro 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 immediately available existing family of very high quality, large aperture, automatic exposure, autofocusing, and sometimes even optical image stablilized Four Thirds lenses made by Olympus, Panasonic and Leica.
The latest range of Olympus Pen cameras (the E-P3, the light E-PL3 and the new mini version, 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.


Concept model of MFT camera by Olympus
Advantages, disadvantages and other factors

Compared to existing compact cameras, which are equipped with non-interchangeable lenses and smaller in area image sensors, MFT are intended to offer interchangeable lenses and the much larger in area sensors used by Four Thirds DSLRs. MFT cameras can be much smaller and lighter than DSLRs, but are larger and heavier than contemporary compact cameras. MFT cameras can offer a great variety of lenses some of which can feature wider apertures than those available on many compacts, allowing more control over depth-of-field and yielding greater creative possibilities.
The much shorter flange focal distance enabled by the removal of the mirror allows normal and wideangle lenses to be made significantly smaller and cheaper 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 35mm film camera. This means that the actual focal length of a MFT lens is half that of 35mm film camera lens. Practically speaking, this means that if a 50mm "normal" lens on 35mm film cameras (or full frame DSLRs) were used on a MFT body, that lens would have a field of view equivalent to 100mm. Said another way, normal lenses on MFT cameras would be only 25mm. For this reason, MFT lenses can be smaller and lighter because to achieve the equivalent 35mm 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 (35mm) 1.0, and Four Thirds 2.0.

Advantages of Micro Four Thirds over Four Thirds DSLR cameras

  • Smaller and lighter with easier to use controls
  • Extensive range from low cost upwards
  • The shorter flange focal distance means that practically all 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 lower materials and manufacturing cost, with smaller and lighter lens equivalents.
  • Phase shift's forward or back focus does not occur with contrast focus, and likewise each lens does not have to be individually calibrated to each camera, which can be required for DSLR to have accurate focus.
  • The absence of a mirror eliminates the need for an additional precision assembly, along with its "mirror slap" noise and vibration.
  • The viewfinder can be used in video mode, since there is no difference between stills and videos in terms of operation.
  • 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.

Advantages of Micro Four Thirds over larger DSLR cameras

Other advantages compared with larger format sensor full frame are:
  • The smaller sensor size may allow for lower lens manufacture cost- in particular, smaller and lighter telephoto-lens equivalents.
  • The smaller flange distance allows for easier to manufacture wide lenses (lighter, potentially cheaper and/or better quality)
  • Smaller and lighter cameras and lenses allow discretion and portability with high quality.
  • Simpler design allows for a potentially lower selling price (however this hasn't happened yet)
  • The smaller sensor size gives deeper depth-of-field for the same equivalent field of view and aperture.
  • Combination of near-professional video and still photo in one package
  • A fast developing technology that promises more innovations

Advantages of electronic viewfinder

The electronic viewfinder has the following advantages, though many DSLRs also have "live view" functionality, although these function relatively poorly compared to Micro Four Thirds
  • Real-time preview of exposure, white balance and tone.
  • Brighter viewfinder in low light.
  • The viewfinder can zoom into one's preview, which a mirror cannot do. Hence as an example, manual focus can be much more precise
  • The viewfinder looks at how the sensor will see one's potential picture, rather than an optical view, which may differ
  • Larger view than many optical screens
  • Not reliant on a moving mirror
  • No weight or size penalty for better quality of materials and design as optical viewfinder quality varies greatly across all DSLRs
In addition, all current Micro Four Thirds cameras have sensor dust removal technologies, but this is not related to the format.

Disadvantages of Micro Four Thirds compared to DSLRs

  • The sensor is 40% smaller in area (2.0 crop factor) than APS-C (1.6 crop factor) sized sensors and 75% smaller (ie a quarter of the area) than a Full Frame sensor (1.0 crop factor) (35mm equivalent) which can lead to lower image quality than an APS-C and much more than Full Frame based DSLR cameras with a similar pixel count; typically this is seen as increased levels of ISO noise in darker situations
  • Contrast detect autofocus were slower (albeit more accurate) than the phase detect systems used in advanced DSLRs. This gap was narrowed with the introduction of the Panasonic Lumix DMC-GH2, and G3, and now Olympus's announced (but not yet shipping) cameras claim to have faster focus than any DSLR equipped with bundled lenses. Fast moving objects moving towards or away from the camera (ie for sports photography) with a top lens should see a Sports DSLR is less certain, especially in low light with expensive sports lenses.
  • 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 (available on all but the first Olympus Pen E-P1 model ), a separate optical viewfinder (similar to a rangefinder or TLR), or the universally supplied LCD screen can be used instead;
  • Changing lenses can expose the sensor to more dust (a problem with all 'mirrorless' interchangeable lens digital camera designs), compared to DSLRs which have both a mirror and a closed shutter protecting the sensor. All current Micro Four Thirds cameras add highly efficient dust removal systems.
  • Larger crop factor (2x multiplier versus APS-C's 1.6x) means greater depth-of-field for the same equivalent field of view and f/stop on full frame cameras. This is a slight disadvantage in achieving out-of-focus backgrounds compared to APS-C but significant compared to Full Frame (1.0x multiplier).

Advantages of Micro Four Thirds over compact digital cameras

  • Greatly increased sensor size (5–9 times larger) 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.

Micro Four Thirds system cameras

As of Feb 2010, Olympus, Panasonic, Cosina (Voigtlander), Carl Zeiss AG, Jos. Schneider Optische Werke GmbH, Komamura Corporation and Sigma Corporation 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.

Micro Four Thirds lenses

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. For those support fast AF (Imager AF). As of June 2010, there are twenty-four Micro Four Thirds standard lenses which can be used by MFT camera bodies:

Standard zoom lenses
  • Panasonic Lumix 14–45mm f/3.5–5.6 (35mm EFL = 28-90mm)
  • Olympus M.Zuiko Digital 14–42mm f/3.5–5.6 (35mm EFL = 28-84mm)
  • Olympus M.Zuiko Digital II 14–42mm f/3.5–5.6 MSC (35mm EFL = 28-84mm)
  • Panasonic Lumix 14–42mm f/3.5–5.6 (35mm EFL = 28-84mm)
Superzoom lenses
  • Panasonic Lumix 14–140mm HD f/4–5.8 (35mm EFL = 28-280mm)
  • Olympus M.Zuiko Digital ED 14-150mm f/4.0-5.6 MSC (35mm EFL = 28-300mm)
Telephoto zoom lenses
  • Olympus M.Zuiko Digital ED 40-150mm f/4-5.6 MSC (announced September 2010) (35mm EFL = 80-300mm)
  • Panasonic Lumix 45–200mm f/4–5.6 (35mm EFL = 90-400mm)
  • Panasonic Lumix G Vario 100-300mm f/4–5.6, Mega O.I.S. (35mm EFL = 200-600mm)
  • Olympus M.Zuiko Digital ED 75-300mm f/4.8-6.7 MSC (35mm EFL = 150-600mm)
Wide-angle zoom lenses
  • Panasonic Lumix 7–14mm f/4 (35mm EFL = 14-28mm)
  • Olympus M.Zuiko Digital ED 9-18mm f/4.0-5.6 MSC (35mm EFL = 18-36mm)
Prime lenses
  • Panasonic Lumix G 14mm lens f/2.5 ASPH (35mm EFL = 28mm)
  • Olympus M.Zuiko Digital 17mm f/2.8 (35mm EFL = 34mm)
  • Panasonic Lumix 20mm f/1.7 (35mm EFL = 40mm)
  • Panasonic Leica DG Summilux 25mm f/1.4 lens f/1.4 (announced 13 June 2011) (35mm EFL = 50mm)
  • Toy Lens 26mm f/1.4 (announced December 2010)(35mm EFL = 52mm)
  • SLR Magic 35mm f/1.7 (announced August 2009)(35mm EFL = 70mm)
  • Noktor Hyperprime 50mm f/0.95 lens (announced February 2010) (35mm EFL = 100mm) SLR Magic was recently tapped as a new producer of this lens as of May 2011[29]
  • Noktor Hyperprime 12mm f/1.6 lens (35mm EFL = 24mm) (announced June 2011)[30]
  • Olympus M.Zuiko Digital 45mm Olympus 45mm f/1.8 (35mm EFL = 90mm)[31]
  • Olympus M.Zuiko Digital 12mm Olympus 12mm f/2.0 (35mm EFL = 24mm)[32]
  • Voigtländer Nokton 25mm f/0.95 (35mm EFL = 50mm)[33]
Macro lenses
  • Panasonic Leica DG Macro-Elmarit 45mm f/2.8 Asph. (35mm EFL = 90mm)
Fisheyes
  • Panasonic Lumix G Fisheye 8mm f/3.5 (35mm EFL = 16mm fisheye)
  • Samyang 7.5mm 1:3.5 UMC Fish-eye MFT (35mm EFL = 15mm fisheye)
3D lenses
  • Panasonic LUMIX G 12.5mm 3D lens f/12 (35mm EFL = 25mm)
Pinhole
  • Wanderlust Pinwide f/96 - f/128 'lens' cap[34]
Image Stabilization - Different approaches

Of the eleven Panasonic lenses, the 8 mm, 7–14 mm, 14mm and the 20 mm are not image stabilized (IS). 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 even vintage manual focus lenses can make use of the 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.

Lens compactness and mount adaptability

A promise of the Micro Four Thirds standard is reduced lens size and of particular interest are the Panasonic 7-14mm ultra-wideangle (equivalent to 14-28mm in the 35mm film format) and the Olympus M.Zuiko Digital ED 9-18mm ultra wide-angle lens (equivalent to an 18-36mm zoom lens in the 35mm film format). The reduced flange focal distance of Micro Four Thirds enables such extreme wideangle 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.
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. A variety of companies manufacture adapters to use lenses from nearly any legacy lens mount (such lenses, of course, support no automatic functions.)
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.

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

See also

Notes

  1. ^ "Olympus and Panasonic announce Micro Four Thirds". Digital Photography Review. 2008-08-05. http://www.dpreview.com/news/0808/08080501microfourthirds.asp. Retrieved 2008-08-05. 
  2. ^ Panasonic introduces AG-AF100
  3. ^ "No more compromises: The Four Thirds Standard". Olympus Europe. http://www.olympus-europa.com/consumer/dslr_7045.htm. Retrieved 2007-11-09. 
  4. ^ Knaur (October 1, 2002). "Interview". A Digital Eye. Archived from the original on December 5, 2002. http://web.archive.org/web/20021205033057/http://www.a-digital-eye.com/Olympus43Q&A.html. 
  5. ^ http://www.dpreview.com/reviews/panasonicdmcgh1/
  6. ^ http://www.dpreview.com/reviews/panasonicdmcgh2/
  7. ^ a b Novoflex – Adapters for MicroFourThirds Cameras
  8. ^ Etchells, Dave (August 5, 2008). "Micro Four Thirds system". The Imaging Resource. http://www.imaging-resource.com/NEWS/1217960634.html. 
  9. ^ "Panasonic Lumix G1 reviewed". Digital Photography Review. http://www.dpreview.com/reviews/panasonicdmcg1/. 
  10. ^ "Panasonic premieres DMC-GH1 with HD video recording". Digital Photography Review. 2009-03-03. http://www.dpreview.com/news/0903/09030315panasoniclumixdmcgh1.asp. Retrieved 2009-03-11. 
  11. ^ http://www2.panasonic.com/webapp/wcs/stores/servlet/prModelDetail?storeId=11301&catalogId=13251&itemId=292233
  12. ^ http://panasonic.net/avc/lumix/popup/pressrelease/gh1.html#1
  13. ^ http://www.dpreview.com/news/0906/09061601olympusep1.asp
  14. ^ http://panasonic.net/avc/lumix/popup/pressrelease/dmc_gf1.html#1
  15. ^ http://www.dpreview.com/news/0911/09110501olympusep2.asp
  16. ^ "Olympus unveils the affordable Pen". Digital Photography Review. 2010-02-03. http://www.dpreview.com/news/1002/10020305olypenepl1.asp. Retrieved 2010-02-03. 
  17. ^ http://panasonic.net/avc/lumix/popup/pressrelease/g2g10.html#2
  18. ^ http://panasonic.net/avc/lumix/popup/pressrelease/g2g10.html#1
  19. ^ http://panasonic.net/avc/lumix/popup/pressrelease/gh2.html
  20. ^ http://panasonic.net/avc/lumix/popup/pressrelease/gf2.html
  21. ^ http://olympus-imaging.jp/product/dslr/epl1s/index.html
  22. ^ http://www.dpreview.com/news/1101/11010622olympusepl2.asp
  23. ^ http://panasonic.net/avc/lumix/popup/pressrelease/g3.html
  24. ^ http://panasonic.net/avc/lumix/popup/pressrelease/gf3.html
  25. ^ http://www.olympusamerica.com/cpg_section/product.asp?product=1573
  26. ^ http://www.olympusamerica.com/cpg_section/product.asp?product=1572
  27. ^ http://www.olympusamerica.com/cpg_section/product.asp?product=1571
  28. ^ . BCN. http://bcnranking.jp/news/0912/091228_16149.html. Retrieved 2010-03-21. 
  29. ^ http://www.43rumors.com/slrmagic-will-resume-the-noktor-lens-production-and-nokton-next-production-run-in-june/
  30. ^ http://www.43rumors.com/exclusive-on-43rumors-new-noktor-12mm-f1-6-lens/
  31. ^ [1]
  32. ^ [2]
  33. ^ [3]
  34. ^ http://wanderlustcameras.com/products/pinwide.html/
  35. ^ Panasonic announces development of world's first interchangeable 3D lens for Lumix G Micro system, Panasonic

References

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