Firmware update for EF to X Smart Adapter and Speed Booster ULTRA (Windows)

Firmware upgrade for Canon EF to Fuji X mount  T Smart AdapterTM and EF-E Speed Booster® ULTRA 0.71x

 

RELEVANT PRODUCTS

This information is for the following models:

  • Canon EF to Fuji X T Speed Booster® ULTRA 0.71x (MB_SPEF-X-BT1)/ Mark II+ (MB_SPEF-X-BT4)

  • Canon EF to Fuji X T CINE Speed Booster® ULTRA 0.71x (MB_SPEF-X-BT2)/ Mark II (MB_SPEF-X-BT3)/ Mark II+ (MB_SPEF-X-BT5)

  • Canon EF to Fuji X T Smart AdapterTM (MB_EF-X-BT1)/ Mark II+ (MB_EF-X-BT4)

  • Canon EF to Fuji X T CINE Smart AdapterTM (MB_EF-X-BT2)/ Mark II (MB_EF-X-BT3)/ Mark II+ (MB_EF-X-BT5)

Disclaimer: these release notes only highlights significant changes to the firmware. There may have been other changes that are not documented.

 

ABOUT THIS DOWNLOAD

  • Name: Firmware update V1.70 (#2533) for EF-X T Speed Booster® ULTRA 0.71x/ Smart AdapterTM
  • Release date: 18 August 2026
  • Benefits and improvements: 
    • Fixed issue where the camera may sometimes not recognize that a Fujifilm teleconverter has been added or removed but displayed the previous maximum aperture.
    • Corrected SP designation of some Tamron lenses in EXIF, such as Tamron SP 70-300mm f/4-5.6 VC USD A005.
    • PDAF performance improvement, especially for video AF and AF-C. Note that Metabones learns about your lens and your usage pattern as you use your lens normally and improves performance over time. Turn off the camera to let Metabones save what it has learned in its memory.
    • Mark II only: additional PDAF improvement with selected lenses, by additional lens profile data that is specifically tailored for each lens (TruePDAF Technology™). Visit our web site for a list of supported lenses. The LED turns pinkish white to indicate that your lens is supported. A white LED indicates that no matching lens profile is found but it will still operate at a slightly lower level of performance.
    • Fixed issue with occasionally inaccurate focal length in EXIF when certain zoom lenses are used.

 

 

FIRMWARE HISTORY: 

  • More firmware history can be viewed in the archive: here

 

 

SYSTEM REQUIREMENTS:

Operating Systems

The latest version of the firmware update is compatible with most commonly-used versions of Microsoft Windows:

  • Windows® 10 1809 or newer (64-bit)
  • Windows® 11
  • Windows® 11 on Arm

A micro-USB cable is required to connect the Smart AdapterTM or Speed Booster® to the computer.

While performing the firmware update, don't disconnect the USB cable, otherwise, the adapter may become inoperable due to sudden disconnection. In most cases, an adapter made inoperable by an interrupted firmware update can be fixed by performing the firmware update again.

Don't connect the adapter to any camara or lens while performing the firmware update.