What's the crop factor of Micro Four Thirds compared to full-frame?

2× — a 25 mm MFT lens has the same horizontal field-of-view as a 50 mm full-frame lens. The sensor is 17.3 × 13 mm with a 4:3 aspect ratio (hence "Four Thirds"). All focal-length and depth-of-field comparisons against full-frame must factor in this 2× multiplier; an MFT 25 mm f/1.4 gives roughly the same DOF as a full-frame 50 mm f/2.8.

Which bodies use the Micro Four Thirds mount?

All OM System / Olympus bodies (OM-1 Mark II, OM-5, E-M10 Mark IV, Pen E-P7) and all Panasonic Lumix G bodies (G9 II, GH7, GH6, GH5 II, G100D, GX9). Both manufacturers ship native lenses, plus a deep third-party lineup (Sigma, Tamron, Voigtländer, Laowa, Leica via Panasonic licensing). Blackmagic Pocket Cinema Camera 4K and DJI Air drone gimbals also use MFT.

Are there AF-preserving Canon EF-to-MFT adapters?

Limited — the Viltrox EF-M2 II Speed Booster brings EF lenses to MFT with 0.71× focal reduction and AF on a narrow whitelist (mostly Canon-brand and a few Sigma EF primes). Most EF-to-MFT adapters are dumb mechanical rings without AF. The MFT-native fast-prime lineup (Olympus M.Zuiko 25 mm f/1.2 Pro, Panasonic Leica DG Summilux 25 mm f/1.4 II) is strong enough that EF adaptation is rarely the path most MFT users take.

Olympus / OM System / Panasonic · Mirrorless mount

Micro Four Thirds — flange distance, protocol, and adapter compatibility

Open standard mirrorless mount co-developed by Olympus (now OM System) and Panasonic. 2× crop factor sensor with a 19.25 mm flange is well-suited to legacy-lens adaptation; the small image circle requirement means almost any full-frame lens covers it. Native AF-preserving EF adapter coverage is limited compared to E-mount.

Mount specifications

Flange focal distance: 19.25 mm
Throat diameter: 38 mm
Electronic protocol: Micro Four Thirds
Supported formats: MFT
Manufacturer: Olympus / OM System / Panasonic
Introduced: 2008
Status: Active production

Micro Four Thirds on the flange-distance axis

Micro Four Thirds sits at 19.25 mm — highlighted in orange below. The flange-distance gap between the mirrorless and SLR clusters is the room a mechanical adapter occupies; that gap is why almost every SLR lens adapts onto every mirrorless body, and why the reverse is mechanically impossible.

Flange focal distance (mm)SLR / DSLRMirrorlessRangefinderMedium-format mirrorlessCinemaLegacy SLR

Adapting Micro Four Thirds lenses onto other bodies

You own Micro Four Thirds glass and want to mount it on a body with a different lens mount. Rows are sorted by feasibility.

Body mount	Result	Adapter examples	Caveats
Body mount Nikon Z flange 16 mm	Mechanical MFIS lens-onlyAp. wheelvignettes	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Micro Four Thirds lens and Nikon Z body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Body mount Canon RF flange 20 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only -0.8 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Micro Four Thirds lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Canon RF (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Canon EF-M flange 18 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only 1.3 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Micro Four Thirds lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Canon EF-M (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Sony E (incl. FE) flange 18 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only 1.3 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Micro Four Thirds lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Sony E (incl. FE) (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Fujifilm X flange 17.7 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only 1.6 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Micro Four Thirds lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Fujifilm X (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Fujifilm GFX (G-mount) flange 26.7 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only -7.4 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Micro Four Thirds lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Fujifilm GFX (G-mount) (medium-format), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 28.0 mm 35.5 mm × 0.79× (medium-format sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount L-Mount flange 20 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only -0.8 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Micro Four Thirds lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a L-Mount (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Leica M flange 27.8 mm	Speed booster MFIS lens-onlyAp. wheelvignettes	Speed Booster / focal-reducer family	Flange clearance is only -8.6 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Micro Four Thirds lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Leica M (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.

Adapting other lenses onto a Micro Four Thirds body

You own a Micro Four Thirds body and want to mount glass from other systems. Mirrorless-lens-onto-DSLR-body combinations are omitted (rear element collides with the mirror box).

Lens mount	Result	Adapter examples	Caveats
Lens mount Canon EF flange 44 mm	Mechanical AF partialIS fullAp. electronic2× crop	Viltrox EF-M2 II (0.71× focal reducer, electronic) Metabones EF-MFT Speed Booster / Smart Adapter	Smart EF-MFT adapters pass electronic aperture and in-lens IS, and drive autofocus — but Micro Four Thirds bodies focus adapted EF glass by contrast-detect only, so AF is usable yet slower than native (hence partial). 2× crop applies on a straight adapter; a 0.71× focal-reducer variant (Viltrox EF-M2, Metabones Speed Booster) pulls the field of view back toward the EF lens's native angle and adds roughly one stop of light.
Lens mount Canon EF-S flange 44 mm	Mechanical AF partialIS fullAp. electronic1.33× crop	Viltrox EF-M2 II (0.71× focal reducer, electronic) Metabones EF-MFT Speed Booster / Smart Adapter	EF-S is electronically EF, so the same smart EF-MFT adapters pass aperture / IS and drive contrast-detect AF on EF-S glass (partial — usable but slower than native). The Micro Four Thirds sensor is smaller than EF-S's APS-C image circle, so coverage is never an issue; a focal-reducer variant restores reach and a stop of light.
Lens mount Canon FD flange 42 mm	Mechanical MFno ISAp. ring2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon FD lens and Micro Four Thirds body.
Lens mount Nikon F flange 46.5 mm	Mechanical MFIS lens-onlyAp. wheel2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Nikon F lens and Micro Four Thirds body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Lens mount Sony A / Minolta A flange 44.5 mm	Mechanical MFIS lens-onlyAp. wheel2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Sony A / Minolta A lens and Micro Four Thirds body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Lens mount Fujifilm GFX (G-mount) flange 26.7 mm	Mechanical MFIS lens-onlyAp. wheel2.53× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Fujifilm GFX (G-mount) lens and Micro Four Thirds body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Lens mount M42 (Pentax / Praktica screw mount) flange 45.46 mm	Mechanical MFno ISAp. ring2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between M42 (Pentax / Praktica screw mount) lens and Micro Four Thirds body.
Lens mount Leica M flange 27.8 mm	Mechanical MFno ISAp. ring2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Leica M lens and Micro Four Thirds body.
Lens mount Pentax K flange 45.46 mm	Mechanical MFIS lens-onlyAp. wheel2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Pentax K lens and Micro Four Thirds body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Lens mount PL (Positive Lock) flange 52 mm	Mechanical MFno ISAp. ring2× crop	Wooden Camera PL-MFT Metabones PL-MFT	2× crop applies — Super-35 PL primes give a ~4× full-frame equivalent. Useful on BMPCC 4K / 6K (BMPCC 4K is actually MFT mount), GH5, GH6.
Lens mount Canon EF (cine) flange 44 mm	Mechanical MFno ISAp. electronic2× crop	Metabones EF-MFT Speed Booster XL (0.64× focal reducer, electronic) Viltrox EF-M2 II (0.71× focal reducer, electronic)	Smart EF-MFT adapters carry the EF 8-pin protocol and pass a CN-E prime's electronic iris; the Metabones EF-MFT Speed Booster XL and Viltrox EF-M2 II are focal reducers that also widen the field of view back toward Super35 and add roughly a stop. On a straight (non-reducing) adapter the 2× crop turns a CN-E 50 into a ~100 mm-equivalent and a CN-E 85 into ~170 mm — a tele-leaning kit; the focal reducer is what restores wider framing.
Lens mount Exakta flange 44.7 mm	Mechanical MFno ISAp. ring2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Exakta lens and Micro Four Thirds body.
Lens mount T-mount (T2) flange 55 mm	Mechanical MFno ISAp. ring2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between T-mount (T2) lens and Micro Four Thirds body.
Lens mount C-mount flange 17.526 mm	Mechanical MFno ISAp. ringvignettes	Generic C-MFT thin spacer (Fotodiox, Rainbowimaging, Kipon)	C-mount flange is 17.526 mm vs MFT's 19.25 mm — adapter is a thin 1.7 mm spacer. Most C-mount lenses focus past infinity through such an adapter; check per-lens. Image circle is sized for 16 mm cine film (~13 mm diagonal). Only a handful of fast cine primes (Cosmicar / Pentax 25 mm f/1.4, Fujian 35 mm f/1.7) cover the MFT sensor; most others vignette into a tight central circle.
Lens mount Praktica B flange 44.4 mm	Mechanical MFno ISAp. ring2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Praktica B lens and Micro Four Thirds body.
Lens mount Konica AR flange 40.5 mm	Mechanical MFno ISAp. ring2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Konica AR lens and Micro Four Thirds body.
Lens mount Minolta SR / MC / MD flange 43.5 mm	Mechanical MFno ISAp. ring2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Minolta SR / MC / MD lens and Micro Four Thirds body.
Lens mount Olympus OM flange 46 mm	Mechanical MFno ISAp. ring2× crop	Olympus MMF-3 (weather-sealed first-party) Fotodiox Pro OM-MFT K&F Concept OM-M43 Urth OM to Micro Four Thirds Adapter	26.75 mm flange clearance — generous adapter thickness; every Zuiko OM lens hits infinity without optical correction. Every Zuiko OM lens is manual-focus with a mechanical aperture ring. Stop-down metering and focus-confirm work on the body's EVF; autofocus, electronic aperture, and IS pass-through are not available (no electrical contacts).
Lens mount Contax/Yashica (C/Y) flange 45.5 mm	Mechanical MFno ISAp. ring2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Contax/Yashica (C/Y) lens and Micro Four Thirds body.
Lens mount Canon RF flange 20 mm	Speed booster MFIS lens-onlyAp. wheel2× crop	Speed Booster / focal-reducer family	Flange clearance is only 0.8 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Lens mount Canon EF-M flange 18 mm	Speed booster MFIS lens-onlyAp. wheel1.33× crop	Speed Booster / focal-reducer family	Flange clearance is only -1.3 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Lens mount Nikon Z flange 16 mm	Speed booster MFIS lens-onlyAp. wheel2× crop	Speed Booster / focal-reducer family	Flange clearance is only -3.3 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Lens mount Sony E (incl. FE) flange 18 mm	Speed booster MFIS lens-onlyAp. wheel2× crop	Speed Booster / focal-reducer family	Flange clearance is only -1.3 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Lens mount Fujifilm X flange 17.7 mm	Speed booster MFIS lens-onlyAp. wheel1.33× crop	Speed Booster / focal-reducer family	Flange clearance is only -1.6 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Lens mount L-Mount flange 20 mm	Speed booster MFIS lens-onlyAp. wheel2× crop	Speed Booster / focal-reducer family	Flange clearance is only 0.8 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Lens mount Canon RF (cine) flange 20 mm	Speed booster MFIS lens-onlyAp. wheel2× crop	Speed Booster / focal-reducer family	Flange clearance is only 0.8 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.

Adapter SKU teardown

Curated adapter SKUs that involve the Micro Four Thirds mount on either side, with the operational specifics — body-side electronic contact count, firmware-update path, weather sealing, and whether optical glass is in the path.

Kipon Baveyes M42-MFT 0.7x
released 2016
M42 (Pentax / Praktica screw mount) lens → Micro Four Thirds body
- no firmware updates
- not weather sealed
- optical glass in path (focal reducer)
- 0.7× focal reducer (Caldwell-licensed optics) for M42 screw-mount lenses onto Micro Four Thirds bodies (OM-1 II / OM-5 / G9 II / GH7 / Pen E-P7). ~1 stop wider effective aperture and reduced 2× crop factor (effective ~1.4×).
- Purely optical — no electronics, no AF, no firmware. M42 lens aperture handled by the lens's own ring or stop-down lever. Lets vintage M42 wides (Helios 44-2 58 mm f/2, Mir-1 37 mm f/2.8, Carl Zeiss Jena Flektogon 35 mm f/2.4) regain something closer to their original field-of-view on MFT.
Viltrox EF-M2 II
released 2018
Canon EF lens → Micro Four Thirds body
- 11 body-side contacts
- firmware updatable
- not weather sealed
- optical glass in path (focal reducer)
- 0.71× focal-reducer ('speed booster') for Canon EF / EF-S glass on Micro Four Thirds bodies — recovers roughly one stop of light and widens the field of view, pulling the effective crop from the bare 2.0× MFT factor toward ~1.42×.
- Autofocus supported for EF / EF-S lenses (single-shot AF reliable; continuous AF noticeably slower than native MFT glass). Forwards electronic aperture and EXIF; firmware-updatable via micro-USB.
- A Canon EF 50 mm f/1.8 behaves close to a 71 mm f/1.3-equivalent in full-frame field-of-view + depth-of-field terms on the 2× sensor; an EF 24 mm f/2.8 widens to roughly a 34 mm f/2.0-equivalent.
Firmware history
1. v1.002018
  - Initial release of the revised 'II' — improved AF firmware and coatings over the original EF-M2
  - 0.71× focal reduction with single-shot AF, electronic aperture, EXIF and in-lens IS pass-through for Canon EF / EF-S glass on Micro Four Thirds bodies, updatable over micro-USB
2. v2.002020
  - AF-tuning refinements and an expanded EF / EF-S + Sigma / Tamron EF lens-compatibility list
  - More reliable single-shot AF on Panasonic GH5 / G9 and Olympus OM-D E-M1 Mark II bodies
Approximate milestones — verify against the Viltrox firmware page for the authoritative changelog.

References

https://en.wikipedia.org/wiki/Micro_Four_Thirds_system

Common questions

What's the crop factor of Micro Four Thirds compared to full-frame?: 2× — a 25 mm MFT lens has the same horizontal field-of-view as a 50 mm full-frame lens. The sensor is 17.3 × 13 mm with a 4:3 aspect ratio (hence "Four Thirds"). All focal-length and depth-of-field comparisons against full-frame must factor in this 2× multiplier; an MFT 25 mm f/1.4 gives roughly the same DOF as a full-frame 50 mm f/2.8.
Which bodies use the Micro Four Thirds mount?: All OM System / Olympus bodies (OM-1 Mark II, OM-5, E-M10 Mark IV, Pen E-P7) and all Panasonic Lumix G bodies (G9 II, GH7, GH6, GH5 II, G100D, GX9). Both manufacturers ship native lenses, plus a deep third-party lineup (Sigma, Tamron, Voigtländer, Laowa, Leica via Panasonic licensing). Blackmagic Pocket Cinema Camera 4K and DJI Air drone gimbals also use MFT.
Are there AF-preserving Canon EF-to-MFT adapters?: Limited — the Viltrox EF-M2 II Speed Booster brings EF lenses to MFT with 0.71× focal reduction and AF on a narrow whitelist (mostly Canon-brand and a few Sigma EF primes). Most EF-to-MFT adapters are dumb mechanical rings without AF. The MFT-native fast-prime lineup (Olympus M.Zuiko 25 mm f/1.2 Pro, Panasonic Leica DG Summilux 25 mm f/1.4 II) is strong enough that EF adaptation is rarely the path most MFT users take.