Metabones Speed Booster ULTRA II+ and Smart Adapter II+ Announced – with TruePDAF

Lens Accessories

by Alexandra ThompsonAugust 24^th, 2026

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Metabones has refreshed its Canon EF to Fujifilm X adapter lineup with four II+ models, while firmware 1.70 brings its TruePDAF autofocus system to both the new adapters and existing Mark II hardware. Firmware 1.70 improves PDAF by learning from the mounted lens and how it is used, while Mark II and II+ hardware adds TruePDAF using stored profiles for more than 100 supported lenses. Metabones says the gains are especially noticeable in video AF and AF-C. The Speed Booster models retain the long-standing 0.71x reduction, one extra stop of light, and a net crop factor of 1.07x. Prices run from $399 to $699, with availability set for September 2026. Let’s take a closer look.

The four products are the EF-X mount T Speed Booster ULTRA 0.71x II+ (MB_SPEF-X-BT4), the EF-X mount T Smart Adapter II+ (MB_EF-X-BT4) and their CINE counterparts (MB_SPEF-X-BT5 and MB_EF-X-BT5). TruePDAF itself is not new. Metabones introduced it in June 2026 on the EF to Micro Four Thirds Mark II adapters, where the Panasonic GH7 and G9 II served as the reference bodies. What is new is that the system reaches FUJIFILM X mount, and that it arrives as firmware rather than as hardware you have to buy again.

What the II+ badge actually means

This is worth stating plainly, because the naming invites a misreading. Metabones says the II+ hardware shares the same processor as the Mark II adapters released in January 2025, and that II+ refers to additional memory for future expansion which, in the company’s own words, has not been leveraged yet. Anyone who bought a Mark II last year does not need to buy anything: a free upgrade to firmware 1.70 delivers TruePDAF on the hardware already in the bag.

Mark I owners are in a different position. They receive a scaled-down version of 1.70, and Metabones says they can move up to Mark II+ capability through a circuit board replacement arranged with customer service. The announcement does not state what that costs or how long it takes, which will decide whether it is a better deal than simply buying a new unit.

What TruePDAF does

The II+ adapters, and Mark II units running 1.70, store lens profile data for more than 100 Canon, Sigma and Tamron lenses. When the adapter identifies the mounted lens and finds a match, its status LED glows magenta instead of blue, signaling that additional lens metadata is being passed to the camera. Metabones describes this as the same kind of metadata a native lens reports, which is the whole idea: give the FUJIFILM body the information it expects to receive, and its own autofocus algorithms have more to work with. The supported lens lists are published on each product page. Metabones also notes on the product pages that each lens must undergo an initial calibration procedure before the adapter can deliver its intended AF performance.

On its earlier Micro Four Thirds implementation, Metabones said the biggest gains appeared in low light, low contrast, and other difficult focusing conditions. Nothing in the FUJIFILM announcement suggests the mechanism is different here.

The part that learns

The database is only half of it. Metabones states that the adapter “gathers information about the lens as you normally use it and saves what it has learned in its non-volatile memory when you turn off the camera.” The firmware 1.70 release notes are more specific about where that shows up, citing “PDAF performance improvement, especially for video AF and AF-C.”

For a filmmaking audience, that is the more interesting claim by some distance. It is also the more ambitious one, because it means the adapter is not simply translating Canon EF commands into FUJIFILM X commands but attempting to make adapted autofocus behave progressively more like a native system over time. The release notes also flag the tailored per-lens profile portion as Mark II only, so it is worth confirming with Metabones exactly which half of TruePDAF Mark I owners get with the scaled-down build.

Why adapted autofocus is the hard part

Bolting a Canon EF lens onto an X mount body is mechanically trivial, and passing aperture values and EXIF data across is a solved problem. The difficult part is autofocus. The FUJIFILM body needs information about the optical characteristics of a lens it was never designed to communicate with, and the adapter has to translate the relevant data between the Canon EF and FUJIFILM X systems. Missing or approximate information can mean slower or less reliable PDAF, particularly in continuous autofocus.

Metabones is claiming that stored lens-specific data plus behavior learned in use closes some of that gap. That is a reasonable thing to attempt and a difficult thing to verify from a press release. Until these are in hand and pointed at moving subjects, the honest position is that this is a promising approach with unquantified results, and the modes that matter most to our readers, AF-C and video, are precisely the ones that are hardest to judge on paper.

What the 0.71x reduction actually gives you

The optics are unchanged and long established. The Speed Booster ULTRA formula is a five-element, four-group design using ultra-high index tantalum-based optical glass, developed with Caldwell Photographic and first announced back in 2014. Nothing in the II+ release alters it.

The effect is easy to state and easy to garble. A 50mm f/1.4 becomes a 35.5mm f/1.0 on the sensor, since 50 multiplied by 0.71 is 35.5 and the compressed image circle buys a stop. Because that then sits behind FUJIFILM’s 1.5x crop, the framing lands back at roughly what a 50mm gives on full frame, and 1.5 multiplied by 0.71 is where the quoted 1.07x net crop comes from. That is the entire point of a focal reducer: it hands an APS-C camera back the field of view the full-frame lens was designed to produce, and concentrates the light onto the smaller sensor while doing it.

Where the Smart Adapter II+ fits

The Smart Adapter II+ contains no optics. It is for anyone who wants electronic EF to X adaptation without altering the lens’s focal length or aperture, so the sensor still crops as it always did and the lens keeps its marked f-stop. It costs $250 less than the Speed Booster in both tiers, and it gets the same TruePDAF treatment, which for many EF zoom owners will be the deciding factor.

Both families share the supporting feature set: T-stop display with supported cinema lenses, smooth iris for gradual aperture transitions with supported Canon, Sigma and Tamron lenses, optimized support for in-body and optical stabilization, a flocked interior to cut internal reflections, a rubber gasket sealing the X mount connection against dust and moisture, and a removable Arca-Swiss compatible tripod foot. A push button on the adapter switches between IBIS and no stabilization while OIS is off, and calls up the camera’s manual lens selection menu for configuring manual focus glass.

CINE versus standard

The one hardware distinction between the tiers is the mount. The CINE models carry a cine-style positive-locking mechanism that Metabones says eliminates play during focusing or zooming, which stops being an abstract concern the moment you hang a heavy zoom and a follow focus off the front. The CINE bodies are correspondingly larger and heavier, at 225g (7.9 oz) for the CINE Speed Booster ULTRA II+ against 180g (6.34 oz) for the standard version, and 204g (7.19 oz) against 144g (5.07 oz) on the Smart Adapter side. Every other listed feature appears on both tiers.

Which FUJIFILM cameras are supported

The fine print matters here. Metabones states that PDAF support requires the higher-end FUJIFILM bodies: the X-H series, X-T2 and newer, and X-Pro2 and newer. T-stop display and smooth iris are listed for X-H, X-T2 and newer, and the X-S series. Owners of older or entry-level X mount cameras should read the compatibility notes before ordering, because the feature carrying this announcement has the narrowest camera support in the package.

Firmware 1.70 and a new odd and even release policy

Firmware 1.70 is available for Mac, Linux and Windows, and Metabones is changing how updates are distributed across generations. After 1.70, odd-numbered releases will be Performance Releases available only to Mark II and Mark II+ hardware, while even-numbered releases will be Stable Releases that continue to support Mark I owners as well. It is a tidy way to keep older hardware supported without holding back the newer processor, though it does mean Mark I owners will be watching feature announcements they cannot fully act on.

Pricing and availability

The EF-X mount T Speed Booster ULTRA 0.71x II+ is $649, and the EF-X mount T Smart Adapter II+ is $399. The CINE versions are $699 and $449, respectively. All four are scheduled for September 2026 through Metabones’ worldwide reseller network and its own webstore. The CINE Speed Booster ULTRA II+ arrives at the same $699 price as the CINE Mark II launched at in early 2025, while only $50 separates the standard and CINE versions of each adapter. On that spread, the locking mount is an easy call for anyone working with a follow focus.

Full details and the supported lens lists are on the Metabones announcement page and the individual product pages.

If you already own a Mark II adapter, firmware 1.70 makes this a free upgrade. Would TruePDAF make you trust adapted autofocus for AF-C or video? Let us know in the comments below!