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Metabones T Speed Booster Ultra 0.71x Adapter for Canon Full-Frame EF-Mount Lens to Canon RF-Mount Camera

BH #MEBSEFEFRBT1 • MFR #MBSPEF-EFR-BT1
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Metabones T Speed Booster Ultra 0.71x Adapter for Canon Full-Frame EF-Mount Lens to Canon RF-Mount Camera
Key Features
  • Canon EF Lens to Canon RF Body
  • Full-Frame Lens to RF Camera Body
  • For UHD 4K Video Capture
  • 0.71x UHD 4K Crop Factor Compensation
This T Speed Booster Ultra 0.71x Adapter from Metabones allows a full-frame Canon EF-mount lens to be used on a Canon RF-mount camera. While providing a one-stop increase for the camera over the lens's aperture range, up to a maximum output aperture of f/0.9, the adapter's optics help to maximize the connected lens's apparent angle of view during UHD 4K video capture.
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Metabones MBSPEF-EFR-BT1 Overview

This T Speed Booster Ultra 0.71x Adapter from Metabones allows a full-frame Canon EF-mount lens to be used on a Canon RF-mount camera. While providing a one-stop increase for the camera over the lens's aperture range, up to a maximum output aperture of f/0.9, the adapter's optics help to maximize the connected lens's apparent angle of view during UHD 4K video capture.

When recording UHD 4K video, a Canon RF-mount camera is only able to capture the center portion of the image projected on its sensor, creating an in-camera "crop factor." A Canon EOS R Mirrorless Digital Camera Body and a Canon EOS RP Mirrorless Digital Camera Body feature a UHD 4K crop factor of 1.75x. Inside this adapter, five optical elements in four groups condenses the light from the full-frame lens and effectively reduces the crop factor to 1.24x. This also makes available to the sensor an additional one stop of light throughout the lens's aperture range.

This adapter is constructed from aluminum alloy for durability while minimizing weight and its mounting rings are made with brass to further prevent wear-and-tear. An internal, matte black coating prevents the appearance of reflections within the adapter barrel, and to help reduce stress on the camera mount when placed on a tripod, the adapter includes a detachable Arca-type compatible tripod foot with 1/4"-20 threads.

This T Speed Booster Ultra 0.71x Adapter supports electronic communication between an attached camera and lens. If the lens includes autofocus, image stabilization, as well as camera-controlled aperture functions, this adapter is intended to allow use of those features. Also, if an attached lens is capable of generating EXIF metadata when used with a directly compatible camera, this adapter is designed to transfer that information, so it can be saved along with image files generated the combined Canon EF-mount lens and Canon EF-M mount camera.

  • Allows a full-frame Canon EF-mount lens to be used on a Canon RF-mount camera
  • Supports electronic communication between camera and lens to enable autofocus, image stabilization, on-camera aperture control, and EXIF metadata generation when possible
  • 0.71x magnification maximizes angle of view of combined camera and lens for UHD 4K video capture
  • Provides a 1-stop increase for the camera over the lens's aperture range, up to a maximum output aperture of f/0.9
  • Reduces Canon EOS R Mirrorless Digital Camera Body UHD 4K video capture crop factor from 1.75x to 1.24x
  • Allows still image capture with a compatible camera set to APS-C mode
  • Integrated jog dial with press-to-click action can be assigned custom functions when used with a compatible camera
  • Five lens elements in four groups for optical clarity as well as color fidelity
  • Internal, black matte coating minimizes the appearance of reflections within the adapter barrel
  • Aluminum alloy components for weight reduction
  • Brass mounting rings prevent wear-and-tear
  • Detachable Arca-type tripod foot with 1/4"-20 threads can be used to reduces stress on a connected camera's mount
  • Locking mechanism for secure attachment of lens with push-button release

Metabones MBSPEF-EFR-BT1 Specs

Item Type
1x Reducing Lens Mount Adapter
Camera Compatibility
Canon RF Mount
Lens Compatibility
Canon EF Mount
Magnification
0.71x
Electronic Communication
Yes
Exposure Change
1-Stop Light Gain
Optical Design
5 Elements in 4 Groups
Included Shims
Mounting
Tripod Mount: 1/4"-20 Female Thread
Materials
Aluminum
Dimensions
Diameter: 2.8" / 71.12 mm
Depth: 0.8" / 20.32 mm
Weight
7.87 oz / 223 g
Packaging Info
Package Weight
0.77 lb
Box Dimensions (LxWxH)
4.3 x 4.1 x 2.4"

Metabones MBSPEF-EFR-BT1 Reviews

Great Speedbooster!

By Ronald
Rated 5 out of 5
Date: 2024-08-11

This speedbooster works well with the lenses I want to use it with. Canon R7 with a few Sigma lenses. It yields great image quality with my 150-600 contemporary lens and gives me F3.5-F4.5. With the 1.6x crop thats still well over 600mm at F4.5. And over 1200mm shooting 4k crop mode on the R7. Its faster than the lens by itself at this focal length and image quality is still fantastic. Highly recommended for the R7 if you need more speed or even wider angle with your EF lenses on the R7.

Great Product

By Charles
Rated 5 out of 5
Date: 2024-03-12

I purchased the Speedbooster to permit me to use my full frame lenses in Canon EF mount on my new Canon R10 without the heavy crop I get with my Canon EF to RF adapter. It works flawlessly with my full frame Canon, Tamron & Tokina DSLR lenses, as well as my partial frame Tamron, Tokina, Tokina & Sigma DSLR lenses that have EF mounts. My Tamron 18-250mm F3.5-4.5 won't fill the frame, but my Sigma 30mm F1.4, Tamron 60mm F2.0 Macro & Tokina 10-17mm F 3.5-4.5 fisheye all fill a full frame sensor even though sold for partial frame DSLRs, so work perfectly. The Speedbooster is optically excellent. I have made stunning pictures with it & my R10. It gives me alternate, very desirable focal lengths with my lenses. Example: My 30mm F1.4 Sigma is a normal lens on the R10 with the Canon EF to RF adapter (48mm equivalent) and a high speed 30mm F1.0 wide angle with the Speedbooster (30mm equivalent). Unfortunately the R10 won't permit setting aperatures over F1.4. I asked Canon to provide a firmware update to permit setting aperatures up to .9, which the Metabones Speedbooster can provide. My slower lenses permit the 1 stop increase in max aperture. Although the Speedbooster does not fully correct the field coverage to what I would get if I used my full frame lens on a full frame mirrorless body, I consider that a plus because I bought my full frame lenses for my 35mm film camera. Film gets cropped when printed, scanned or mounted as slides. 35mm camera viewfinders show the cropped view you would get when printed, scanned or as slides. Digital bodies create no crop at all. Therefore they change the effective focal length of all lenses compared to 35mm coverage. The Speedbooster gives me virtually the same coverage as I get when I use my lenses on my 35mm film camera. If I use my 28-80mm lens on a full frame mirrorless digital it effectively becomes a 26-73mm lens. Great on the wide end, but terrible on the tele end. With the Speedbooster it effectively becomes 29-83mm, much closer to what I expected the lens to do when Ipurchased it. I couldn't stand my old film 28-70mm 35mm lens because the tele end was useless, but 83mm is almost perfect. Portrait focal length range on a 35mm camera is 85-105mm. In addition, if I use my partial frame lenses on a full frame 24MP R6 Mk II I get less than 10MP. With the Speedbooster on my R10 I get 24MP & a 1 stop faster lens, a win-win. My 18-55mm partial frame kit lens on my R10 with the Canon adapter vignettes the pop-up flash, but my 28-80mm kit lens on the Speedbooster does not, because the Speedbooster is shorter than the Canon adapter and the lens is shorter at it's wide angle setting than it's partial frame equivalent. I can't say enough good things about this Speedbooster. Autofocus is as fast as on my DSLR or with the Canon adapter. The little jog wheel let's me do what the Canon control ring adapter does, only better because it works even if I have the camera set to use a control ring as a focusing ring. I can easily change exposure compensation. This thing is great. Sorry I couldn't upload photos. The system wouldn't let me on my tablet, but trust me, the pictures out of this thing are phenomenal.

See any errors on this page?

If I put this on an EOS R with the EF 8-15mm ...

If I put this on an EOS R with the EF 8-15mm fisheye lens, will it get rid of the top and bottom crop seen in all video modes at the 8mm full-circle fisheye view, also using current firmware on camera and speedbooster if it has it?
Asked by: Steven
I just tested this for you. So with the original Canon adapter, because of the crop you don't get the full 8mm circle [ in 4K. 1080P you do get the full circle no crop ]. Now with this speed booster, even in 4K you get the full circle at 8mm. So you will get the black edges and the spherical look in the middle.
Answered by: Stephen M
Date published: 2020-07-06

Has anybody tried this with a Canon C70? I have ...

Has anybody tried this with a Canon C70? I have and it seems to be unreliable, almost like it has a bad connection. I don't have another RF camera to test it on other than the C70.
Asked by: Keith
With the firmware V1.40 updated. The Speed Booster is compatible with the Canon C70, EOS R5/R6(in crop mode), and the user can assign the control ring functions to the wheel dial of adapter to adjust the aperture/ISO/WB, etc.
Answered by: Support
Date published: 2021-09-11

For use with an R5, any advantage of this vs. ...

For use with an R5, any advantage of this vs. Canon's $100 Mount Adapter EF-EOS R?
Asked by: Chris
You must read the overview. the Metabones adapter is an optical system that modifies your lens. The Speed Booster Ultra 0.71x Adapter from Metabones allows a full-frame Canon EF-mount lens to be used on a Canon RF-mount camera. While providing a one-stop increase over the lens's aperture range, up to a maximum output aperture of f/0.9, the adapter's optics help to maximize the connected lens's apparent angle of view during UHD 4K video capture. It will also change your lenses angle of view. You are comparing totaly different product designed for totaly diferent outcomes.
Answered by: Gary
Date published: 2020-07-20

So if I put this on the Sigma 24mm f1.4 Prime ...

So if I put this on the Sigma 24mm f1.4 Prime Lens, what would it make the aperture on it? Also does it work with that lens?
Asked by: Tee
This is compatible with the Sigma 24mm f/1.4 DG HSM Art Lens for Canon, and it'll be roughly equivalent to a f/0.9.
Answered by: Kevin
Date published: 2020-07-02

will the assignable wheel be recognized by ...

will the assignable wheel be recognized by komodo? Can you assign it to adjust iris?
Asked by: darin
According to the manufacturer, the RED Komodo camera (firmware V1.5.3) is not compatible with the Control Wheel function of the Metabones T Speed Booster Ultra 0.71x Adapter for Canon Full-Frame EF-Mount Lens to Canon RF-Mount Camera.
Answered by: Manzell L
Date published: 2022-02-14

Will this adapter work for conversion to a super ...

Will this adapter work for conversion to a super 35mm sensor? Particularly to pair with a RED Komodo 6K.
Asked by: Geoff
I have both and it does work on the Komodo, but does not communicate autofocus information.
Answered by: Gery
Date published: 2026-01-07

Would it vignette on the Canon EOS R5/6?

Would it vignette on the Canon EOS R5/6?
Asked by: Andres
won't support Canon R5/R6 with current firmware, so there is no vignette, it's all black screen
Answered by: Nick
Date published: 2022-12-08

Will this also increase the aperture for stills ...

Will this also increase the aperture for stills on any particular lens used?
Asked by: Jorge
Its been a while since I returned mine. I was pumped on it at first. But it came with so many limitations. I remember it not being even useful for photos. Do plenty of research before buying.
Answered by: Chris
Date published: 2020-07-18
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