MB SPEF-E-BT4 NEX -EF ULTRA II - MetabonesEAN  4897050182222

LIMITATION
Optical/mechanical

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".

Autofocus

AF-C is supported on A9, A7RIII, A7III, 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.

Other

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, which 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 erroneously. This is a bug in 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.