How does the Baveyes EF-FX compare to the Fringer EF-FX Pro II?

Different value propositions. Fringer EF-FX Pro II is the highest-AF-quality EF → Fuji X adapter, no focal reducer — preserves the lens's native focal length and image circle. Kipon Baveyes EF-FX is a 0.7× focal reducer with weaker AF but optical reduction that turns full-frame EF lenses into APS-C-equivalent fields-of-view with ~1 stop more light. Pick Fringer for AF tracking; pick Kipon Baveyes for the reduction.

Does v2.0 firmware really improve subject tracking on the X-H2S?

Yes — v2.0 added phase-detect AF refinements specifically for the stacked-sensor X-H2S, plus broader Canon L II / III USM lens compatibility. Tracking is still slower than a native XF lens or the Fringer EF-FX Pro II's tracking AF, but single-point and Wide-area modes both work reliably on the X-H2S / X-T5 after the update.

Will it work on the GFX 100 II or GFX 50R?

No — the EF-FX is X-mount specific. GFX is medium-format mirrorless with a different bayonet. For EF on GFX use the Fringer EF-GFX Pro (no focal reducer — image circle vignettes on full GFX format; switch to 35 mm capture mode for no-vignetting capture).

Kipon · Canon EF → Fujifilm X adapter

Kipon Baveyes EF-FX 0.7x — Canon EF → Fujifilm X adapter

0.7× focal reducer (Caldwell-licensed optics) for Canon EF onto Fujifilm X APS-C bodies. 1 stop wider effective aperture and ~equivalent full-frame field-of-view on the X-mount sensor.

At a glance

Vendor: Kipon
Release year: 2017
Body-side contacts: 9 pins
Flags: firmware-updatableweather-sealed —requires glass

What this adapter preserves

Compatibility for Canon EF lens on a Fujifilm X body (computed from the lensmount dataset — open the Canon EF to Fujifilm X adapter page for the full verdict, flange clearance, and adapter caveats).

Focus: Full AF
IS: IS / IBIS preserved
Aperture: Electronic aperture
Infinity focus: Reaches infinity

Format note: Lens covers full-frame; body is APS-C — 1.5× crop factor applies relative to the lens's native image circle. No vignetting; the body uses the centre of the lens.

What it does

AF on EF USM / STM lenses on X-T5 / X-H2 / X-H2S after v2.0 firmware; tracking is slower than Fringer EF-FX Pro II but optical reduction is the differentiator. USB-C firmware updates from kipon.com.

Firmware history

v1.02017
- Initial release — Canon EF onto Fujifilm X APS-C with 0.7× reduction and basic AF / electronic aperture
v2.02022
- X-T5 / X-H2 / X-H2S phase-detect refinements
- Canon EF L II / III lens compatibility additions

Approximate milestones — verify against the Kipon firmware page for the authoritative changelog.

Try your lens through this focal reducer

Pick a lens focal length, max aperture, target body sensor format, and reducer family below — the calc returns the effective focal length, effective f-number, and full-frame equivalent angle of view on that body. Both focal length and f-number scale by the reducer ratio (so the lens always gets two stops faster, distributed as −2·log₂(ratio) stops).

Speed Booster equivalence calculator

Plug in any Canon EF lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a APS-C body of your choice, plus the full-frame equivalent angle of view after the body's crop stacks on top.

Lens focal length (mm)Max aperture (f/N)Body sensor formatFocal-reducer family

Effective focal length: 35.5 mm
Effective aperture: f/1.28
Full-frame equiv. angle of view: 53.3 mm

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.

Common questions

How does the Baveyes EF-FX compare to the Fringer EF-FX Pro II?: Different value propositions. Fringer EF-FX Pro II is the highest-AF-quality EF → Fuji X adapter, no focal reducer — preserves the lens's native focal length and image circle. Kipon Baveyes EF-FX is a 0.7× focal reducer with weaker AF but optical reduction that turns full-frame EF lenses into APS-C-equivalent fields-of-view with ~1 stop more light. Pick Fringer for AF tracking; pick Kipon Baveyes for the reduction.
Does v2.0 firmware really improve subject tracking on the X-H2S?: Yes — v2.0 added phase-detect AF refinements specifically for the stacked-sensor X-H2S, plus broader Canon L II / III USM lens compatibility. Tracking is still slower than a native XF lens or the Fringer EF-FX Pro II's tracking AF, but single-point and Wide-area modes both work reliably on the X-H2S / X-T5 after the update.
Will it work on the GFX 100 II or GFX 50R?: No — the EF-FX is X-mount specific. GFX is medium-format mirrorless with a different bayonet. For EF on GFX use the Fringer EF-GFX Pro (no focal reducer — image circle vignettes on full GFX format; switch to 35 mm capture mode for no-vignetting capture).

Mounts on either side

Lens side

Canon EF

Flange 44 mm · Canon

Open mount page →

Body side

Fujifilm X

Flange 17.7 mm · Fujifilm

Open mount page →

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