• Advanced 5-element/4-group optical design incorporating ultra-high index tantalum-based optical glass by Caldwell Photographic in the USA (patent pending).
• If both your lens supports optical image stabilization (OIS) and your camera supports sensor-shift, in-body image stabilization (IBIS), the choice is yours on which one to use, or have both of them work in harmony.
• Smooth iris support with the latest Canon (2009+), Tamron (SP series 2013+) and Sigma (2016+) lenses.
• Custom function button (called Focus Hold button) assignable to more than 50 functions, such as Aperture Preview and Eye-AF, on A9, A7 series, A6500 and A6300.
• Cinema EOS lens (CN-E) support, including power zoom, AF and auto iris.
• Detachable tripod foot, compatible with Arca Swiss, Markins and Photo Clam ball heads.

• Increase maximum aperture by 1 stop.
• Increase MTF.
• Makes lens 0.71x wider.
• Felt material flocked inside to reduce internal reflection.

• AF-C tracking during high speed drive at up to 10fps on Sony A9. (NOT applicable to A7R Mark III or A7 Mark III, refer to footnote number [x] of Sony's A7 Mark III press release for limitations.)
• Fast contrast-detection AF on all E-mount cameras (except AF-S/DMF with Sony A9).
• Pure phase-detection autofocus support on A9, A7RII, A7II, A6500 and A6300 (the fastest).
• Supports 5-axis in-body image stabilization of A7II, A7RII and A7SII. (Distance information from lens required; 3-axis IBIS if lens does not transmit distance information.)
• Powered by camera body. No external power source required.
• Efficient switched-mode power supply.
• Supports image stabilization (IS) lenses.
• Supports electronic manual focusing (e.g. EF 85/1.2L II and discontinued EF 50/1.0L)
• EXIF support (focal length, aperture, lens name)
• Distance and zoom display on VG and FS series camcorders, A9, A7 series, A6500 and A6300 (lens with distance information support required).
• Auto magnify (lens with distance information support required)
• Auto "APS-C Size Capture" on full-frame cameras.

• Full-frame lens required. EF-S/DX/DC/Di II lenses are NOT supported.
• Speed Booster ULTRA is designed to cover an APS-C image circle which is not big enough to cover a full-size 36mm x 24mm sensor. On a full frame camera body (A7 series, NEX-VG900) the camera needs to have "APS-C/Super 35mm" set to either "Auto" or "On".

• AF-C is supported on A9, A7RII, A7II, A6500 and A6300 only, and only in Green mode.
• Continuous video AF is functional in Advanced mode, but performance may be unsatisfactory.
• On Sony A9, only phase-detection autofocus is supported. Contrast-detection autofocus does not work. See firmware release notes for details.
• AF may not work if the maximum aperture of the lens plus any EF Extender or other teleconverter attached is smaller than f/8 before boost or smaller than f/5.6 after boost.
• The first two autofocus attempts are used to calibrate the lens and as a result may not lock successfully on the target. Half-press the shutter release button again and autofocus will lock successfully.
• Autofocus may have difficultly locking onto subjects which are very close to the nearest focusing distance of the lens.
• Autofocus accuracy depends heavily on the design and working condition of the lens. Lenses with hidden problems which may not be apparent on Canon DSLRs will lead to inaccurate and unreliable autofocus on Sony. Typical problems of this kind that we have seen include an unsmooth/erratic autofocus mechanism (e.g. getting stuck intermittently at a certain focusing distance), a faulty/worn-out distance encoder or other faulty/worn-out internal sensors.

• No support for lens corrections such as peripheral shading, CA and distortion.
• Use of Canon Cinema lenses such as CN-E 18-80mm T4.4 for still photography is not supported. (Functional, but slower than lenses designed for still photography.)
• Some EF-mount lenses may make audible noises during iris changes and autofocus, wich may be picked up by the built-in microphone of the camera during video recording. Use of an external microphone is advised. Some of the recently-introduced Canon-brand lenses are very quiet, however.
• Early Tamron VC lenses such as the AF 28-300/3.5-6.3 XR Di VC LD Aspherical [IF] Macro (model A20), AF 18-270/3.5-6.3 Di II VC LD Aspherical [IF] MACRO (model B003), SP AF 17-50mm F/2.8 XR Di II VC LD Aspherical [IF] (model B005) may not be able to freely switch between OIS and IBIS because they may not report IS activity status. Later Tamron VC lenses equipped with USD or PZD focus motors are fine.
• Some aftermarket battery grips may cause the aperture to change erraneously. This is a bug of the aftermarket battery grip but NOT arising from the Metabones Speed Booster. Turn off the aftermarket battery grip or use a genuine Sony battery grip.

Contax/Yashica

Leica R

Nikon F

Olympus OM

Pentax K