The Speed Booster Ultra 0.71x Adapter for Leica R-Mount Lens to Micro Four Thirds-Mount Camera from Metabones allows a Leica R-mount lens to be mounted onto a Micro Four Thirds-mount camera. While doing so, the adapter's optics help to maximize the connected lens's apparent angle of view while providing a 1-stop increase for the camera over the lens's aperture range.

If a lens intended for 35mm film or similarly-sized full-frame camera sensors is connected to a camera with a Micro Four Thirds-sized sensor, it would project an image larger than the Micro Four Thirds sensor was built to accept. Able to capture only the center portion of the projected image, the effective angle of view of the lens would be narrowed, creating an in-camera "crop factor." The Speed Booster Ultra 0.71x Adapter for Leica R-Mount Lens to Micro Four Thirds-Mount Camera condenses the light from a lens designed for 35mm film or "full frame" camera sensors and projects it onto a Micro Four Thirds sensor. This allows a Micro Four Thirds sensor to utilize more of the light gathered by a connected lens, which effectively reduces the crop factor while making available to the sensor an additional 1 stop of light for each of the lens's f/stop settings.

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. Inside are five lens elements in four groups that are designed to provide optical clarity as well as color fidelity, and a detachable tripod foot is included that features 1/4"-20 threads as well as compatibility with Arca-Swiss tripod heads.

The Speed Booster Ultra 0.71x Adapter for Leica R-Mount Lens to Micro Four Thirds-Mount Camera does not support electronic communication between an attached camera and lens. To help determine the amount of light that enters a Micro Four Thirds-mount camera when using this adapter and a Contax/Yashica-mount lens, users should use the aperture ring found on the lens.

Leica R Lens to Micro 4/3 Body    Full-Frame Lens to Micro 4/3 Camera Body    0.71x Micro 4/3 Crop Factor Compensation    1-Stop Increase in Lens Apertures    5 Optical Elements in 4 Groups    Locking Mechanism to Secure Lens    Push-Button Lens Release    Brass Mounting Rings    Detachable Tripod Foot

• Allows a full-frame Leica R-mount lens to be used with a Micro Four Thirds-mount camera
• Maximizes apparent angle of view of combined camera and lens
• Provides a 1-stop increase for the camera over the lens's aperture range
• Five lens elements in four groups for optical clarity as well as color fidelity
• Detachable, Arca-Swiss compatible tripod foot with 3/8" threads
• Aluminum alloy components for weight reduction
• Brass mounting rings prevent wear-and-tear
• Locking mechanism for secure attachment of lens with push-button release

Related Questions and Answers

Q: 1. Will it accept EF-S lens?

A: The Metabones T Speed Booster Ultra 0.71x Adapter for Canon Full-Frame EF-Mount Lens to Micro Four Thirds-Mount Camera listed above is designed for full-frame Canon EF-mount lenses. According to Metabones' website, EF-S lenses require modification to fit or may remain incompatible even after modification (but third-party DX lenses can be used without modification). Some EF-S and DX lenses may not have enough coverage of the entire image circle for stills after widening by 0.71x (but video will have enough coverage). They also state that the Canon EF-S 18-135mm f/3.5-5.6 IS Nano USM lens will not fit even after modification.

Q: 2. why in the world is this so expensive?

A: Mostly because it can be. But they'd probably tell you it's because it's basically a prime lens with high quality glass and electrical components.

Q: 3. Im trying to use a canon 50mm 1.4 with the speedbooster and I dont get the extra stop of light. I tried with the 24-70 sigma and I got an extra stop.. does anyone knows why it doesnt work with the 50mm?? thanks

A: You are getting the extra stop of light the issue is with the limit within the actual camera readout. I have the 50mm and 80mm and neither 1.4's dead out properly.

Q: 4. Will this perform autofocus + Auto-metering + auto-aperture switching ?Camera = OM-D-EM10Len =Sigma 17-50mm F2.8 EX DC OS HSM for Nikon DX mount.

A: This adapter does not allow for electronic communication between the camera and lens. You would need to focus and adjust aperture manually. You would also likely need to use stop-down metering.

Q: 5. EF-S?

A: Unfortunately speed boosters are not compatible with EF-S lenses.

Q: 6. Can it be applied on Panasonic G9 with autofocus? Thanks.

A: It definitely works on my G7 and numerous other recent models (GH4/GH5) that many of my Panasonic-shooting friends own so the odds are good.

Q: 7. If used with a FF 24-70 lens, would this adapter give the FF equivalent of 38.4-112 (MFT 27.3-79.5)? If so, would the lens still have the same distortion as it's original angles, or would it essentially become a true normal to telephoto lens?

A: Distortion would be a little less..range not quite from normal as wide end is close to a 35mm ff equiv, so more like wide to tele range. FYI, lenses like the 70-200 and 24-105 with IS , can utilize the IS and works nice.

Q: 8. I have a two part question. I recently bought a BMPCC 4K and I’m looking for the perfect combination of Metabones Speedbooster for the Rokinon 35mm Cine Ds lens I’m going to purchase. What would be the best fit for a cinematic feel? Also, I’ve noticed that Rokinon not only has a 35mm lens micro four thirds but a Canon EF option. Which would be the best option of the Rokinon 35mm for me to buy to work with the best Metabones Speedbooster?

A: Since you have not yet purchased the lens we recommend getting MFT mount lenses rather than getting an adapter and EF lenses. You could get the 35mm in MFT, B&H # RO3515MFT, along with getting a wider 16mm T2.2 lens, B&H # RO1622TM43. With the 1.9x Crop Factor the BMPCC4K the lenses will be the equivalent of 30mm and 67mm. 16mm - https://bhpho.to/2j0WaZt 35mm - https://bhpho.to/2mG7DMN

Q: 9. Is this compatible with a JVC GY-LS300?

A: Yes it is compatible with EF (full frame) lenses and your camera (JVC GY-LS300) , they are not compatible with EF-S lenses (APS-C)

Q: 10. I have 3 MFT Veydra lenses and I plan on using them for the BMPCC4k when its out. Is there any kind of metabones speed booster to use on MFT veydra lenses to obtain the advantages of being faster, wider, etc?

A: I'm not 100%, but I don't think you can use a speedbooster in this situation. If you have MFT lenses, you are kind of stuck with the 2.88 crop factor. The BMPCC4K is a MFT lense mount, so if you have MFT, you would be looking for a MFT to MFT speedbooster and I don't think they have that.