Head-to-head · Canon EF → Sony E
Kipon Baveyes EF-FE 0.71× vs Metabones Speed Booster ULTRA EF-E — focal reducers compared
Both are 0.71× focal reducers that adapt Canon EF lenses onto APS-C Sony E bodies, multiplying aperture by ~1 stop and shrinking focal length by 0.71×. Both use Brian Caldwell-licensed optics from the same patent family. The choice comes down to firmware support and per-lens tuning.
Side-by-side specifications
| Spec | Kipon Baveyes EF-FE 0.7x Kipon · 2017 | Metabones Speed Booster ULTRA 0.71× EF-E Metabones · 2014 |
|---|---|---|
| Lens side | Canon EF | Canon EF |
| Body side | Sony E | Sony E |
| Release year | 2017 | 2014 |
| Body-side contacts | 9 pins | 11 pins |
| Firmware-updatable | Yes | Yes |
| Weather-sealed | No | No |
| Has glass (focal reducer) | Yes | Yes |
Differences that matter
Both adapters use the same Caldwell focal-reducer patent family — Metabones licensed the design from Caldwell Photographic; Kipon's Baveyes line licenses from the same source. Optical performance is broadly comparable in the centre; corner performance varies by adapter sample more than by brand.
Firmware updates: Metabones Speed Booster ULTRA updates over the side micro-USB port — shares firmware lineage with the plain EF-E V (v0.51 added PDAF on a6300 / a6500; v0.69 added a6600 tracking with Sigma EF). Kipon Baveyes EF-FE 0.71× is less actively firmware-updated; the cadence is slower and the per-lens chart is shorter.
EF lens chart depth: Metabones' published Speed Booster chart covers Canon L USM, Sigma Global Vision, Tamron G2. Kipon's Baveyes chart is shorter and Tamron coverage is thinner.
Both are APS-C-only on the body side — neither covers a full-frame Sony sensor (a7-series, a1, FX3). The 0.71× ratio concentrates the EF image circle to APS-C size; on a full-frame E body you'd see heavy vignetting or black corners.
Price: Kipon Baveyes is typically 30-40% under Metabones Speed Booster ULTRA at retail. The saving is real; the trade-off is firmware support and chart depth.
Build: both are metal-bodied. Metabones has the more refined feel and the side-USB port for firmware updates. Kipon Baveyes is functional and fits the budget positioning.
When to pick which
Pick the
- You're budget-conscious and the EF lens kit is mainstream (Canon L USM zooms, Sigma EF Art primes already covered by Caldwell's optical design).
- Your shooting is static-subject (portrait, landscape, product) where firmware-driven AF refinements matter less.
- You want a focal reducer to try the concept without committing to the Metabones premium.
Pick the
Metabones Speed Booster ULTRA 0.71× EF-E when
- You want active firmware support and a maintained per-lens compat chart — Metabones publishes both, Kipon is quieter on this front.
- Your EF kit includes Tamron G2 or newer Sigma DG Art / Sports — Metabones' chart covers these more explicitly.
- You shoot on a6300 / a6500 / a6600 with continuous-tracking AF (sports, wildlife on APS-C) where the Metabones firmware track's PDAF refinements matter.
- You already own a Metabones plain EF-E V — adding the Speed Booster from the same vendor keeps firmware behaviour consistent across both adapters.
Common questions
- Will either focal reducer work on a full-frame Sony like the a7 IV?
- No — both are APS-C-only on the body side. The 0.71× ratio concentrates the EF image circle to APS-C size; on a full-frame E body you get heavy vignetting or black corners. For a full-frame Sony body, use the plain Metabones EF-E Mark V or Sigma MC-11 (no focal reduction).
- Do both adapters give the same focal-length and aperture conversion?
- Yes — both are 0.71× ratio reducers, so an EF 50 mm becomes ~35 mm effective on APS-C (close to its native full-frame field of view) and an f/2.8 aperture becomes ~f/2.0 effective. The math is identical; what differs is AF behaviour on specific lens-body combinations.
- Why do both adapters look so similar inside?
- Both license focal-reducer optics from Brian Caldwell's patent family (Caldwell Photographic). Metabones is the licensee Caldwell first partnered with; Kipon's Baveyes line came later but uses the same optical principle. The optical groups are similar in spec; the surrounding electronics and firmware are where the brands diverge.
- Can I update the Kipon Baveyes firmware?
- Less actively than Metabones. Kipon does ship occasional firmware via their service network but the cadence and per-lens compat chart updates are noticeably less frequent than Metabones' once-or-twice-a-year publishing rhythm. For a kit that needs active firmware support as new Sony bodies launch, Metabones is the better pick.
Open the individual adapter pages
- Kipon Baveyes EF-FE 0.7x — full spec, firmware history, per-lens compat notes
- Metabones Speed Booster ULTRA 0.71× EF-E — full spec, firmware history, per-lens compat notes
- Canon EF to Sony E adapter page — every adapter for this mount pair, verdict, format notes
Keep exploring
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