Metabones MB_EF-E-BT4 (MB EF E BT4, MBEFEBT4, MB/EF/E/BT4, mb_ef-e-bt4) Canon EF Lens to Sony E Mount T Smart Adapter (Mark IV)
Features and benefits
Phase-detect autofocus support on A7RII.
Supports 5-axis in-body image stabilization of A7II and A7RII,
Powered by camera body. No external power source required.
Aperture control from camera body.
Wide open button (opposite of depth-of-field preview function) makes manual focusing easy and assignable to a custom function on A7 series.
High performance 32-bit processor and 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, zoom range)
Distance and zoom display on VG and FS series camcorders (lens with distance information support required).
Auto magnify (lens with distance information support required)
Auto "APS-C Size Capture" on full-frame cameras with Canon EF-S lenses and many third party DX lenses.
Fits both EF and EF-S lenses. (Vignetting at corners may occur for certain EF-S lenses because they are designed to cover a 1.6x crop image circle but Sony NEX has a 1.5x crop sensor.)
Flocking material coated inside the opening to reduce internal reflection.
The tripod foot is detachable and compatible with Arca Swiss, Markins, Photo cam ball heads.
Fast phase-detect AF is available only on A7RII. on other Sony cameras, contrast-detect AF with an EF mount lens is disappointingly slow and inadequate for all but static subjects,
Even on A7RII, long telephoto lenses hunt more often and autofocus performance progressively deteriorates as focal length gets longer.
On A7RII, the AF points near the center always work well, but those on the edges and in the corners may lose effectiveness when a fast lens or a telephoto lens is used.
A7RII supports only contrast-detect AF during video recording. This means video AF speed may be unsatisfactory.
During movie capture, autofocus needs to be manually activiated by half-pressing the shutter release button if subject moves to a different distance. Since contrast-detect autofocus speed is slow, there may be visible disruption in the resulting footage.
With PXW-FS7, NEX-FS700 and NEX-FS100, autofocus works only in photo mode but disabled in movie capture mode.
Continuous AF is not supported. (Does not work with contrast-detect AF and may have unsatisfactory performance with phase-detect AF of A7RII.)
Eye AF is not supported.
DMF mode (direct manual focus) is not supported.
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 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 NEX. 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.
Enhancement on new MARK IV (MB_EF-E-BT4) vs. old MARK IV (MB_EF-E-BM4):
The inner opening is lined with flocking material coating. This will further reduce internal reflection when a tilt-shift (TS) lens is used.
Tested Camera Bodies:
A7RII, A7II, A7S, A7R, A7
PXW-FS7, NEX-FS700, NEX-FS100
NEX-EA50, NEX-VG900, NEX-VG30, NEX-VG20, NEX-VG10
NEX-7, NEX-6, NEX-5R, NEX-5N, NEX-5, NEX-C3, NEX-3
EF lenses (see below for list of tested lenses)
EF-S lenses (see note 1)
Image stabilization (IS)
Electronic manual focusing (e.g. EF 85/1.2L II and discontinued EF 50/1.0L)
EXIF (focal length, aperture, zoom range)
P, A, S, M exposure modes
Autofocus (see autofocus support section below)
Distance and zoom display on VG and FS series camcorders (see note 3)
Auto magnify (see note 2)
Contax N mount lenses modified to Canon EF by Conurus
Contax 645 NAM-1 adapter modified to Canon EF by Conurus
Sigma, Tamron and Tokina lenses in Canon EF mount (see note 3)
Lens correction such as peripheral shading, CA and distortion
Focus confirmation "chip" (e.g. Dandelion)
Stacking another lens mount adapter on top (see note 4)
Notes Vignetting at corners may occur for certain EF-S lenses because they are designed to cover a 1.6x crop image circle but Sony NEX has a 1.5x crop sensor.
Requires lenses supporting distance information.
A third party zoom lens may need to be registered with the Smart Adapter first in order to detect its maximum aperture. Autofocus is disabled for most third-party lenses.
For example, some improperly-made M42 screw mount adapters may cause a short-circuit with the electronic contacts of the Smart Adapter and cause damage to the Smart Adapter and/or camera body.
Tested Camera Bodies
A7 (Mark IV supports auto "APS-C Size Capture" with EF-S lens)
A7R (Mark IV supports auto "APS-C Size Capture" with EF-S lens)
NEX-FS700 (autofocus works only in photo mode, but is disabled in movie capture mode)
NEX-FS100 (autofocus works only in photo mode, but is disabled in movie capture mode)
NEX-VG900 (Mark IV supports auto "APS-C Size Capture" with EF-S lens)
Tested Lenses (The following lenses have been tested for autofocus operation. Minimum firmware version required shown in parentheses).
Canon EF primes
EF 14/2.8L II USM
EF 24/1.4L II USM
EF 24/2.8 IS USM
EF 35/1.4L USM (Ver.19)
EF 50/1.2L USM
EF 85/1.2L II USM
EF 85/1.8 USM (Ver.18)
EF 100/2.8 USM macro (Ver.17)
EF 135/2L USM (Ver.17)
EF 200/2.8L II USM (Ver.17)
EF 300/2.8L IS USM
Extender EF 1.4x III
Extender EF 2x (mark I)
Canon EF zooms
EF 8-15/4L USM fisheye
EF 17-40/4L USM
EF 20-35/2.8L (Ver.18)
EF 22-55/4-5.6 USM
EF 24-70/2.8L USM II
EF 28-80/3.5-5.6 II (Ver.18)
EF 28-90/4-5.6 III
EF 35-350/3.5-5.6L (Ver.18)
EF 70-200/2.8L IS USM II
EF 70-200/4L USM
EF 70-200/4L IS USM
EF 70-300/4-5.6L IS USM
EF 70-300/4-5.6 IS USM
EF 100-300/5.6 (non-L, not USM, push-pull zoom) (Ver.18)
EF 100-400/4.5-5.6L IS USM
EF-S 10-22/3.5-4.5 USM
EF-S 17-55/2.8 IS USM
EF-S 17-85/4-5.6 IS USM
EF-S 18-55/3.5-5.6 IS
EF-S 18-135/3.5-5.6 IS
EF-S 60/2.8 macro USM
17-70/2.8-4 DC OS HSM (Ver.15)
30/1.4 DC HSM old version (Ver.18)
SP 24-70/2.8 Di VC USD A007 (Ver.15)
SP 70-200/2.8 Di VC USD A009 (Ver.31)
Tokina (full frame)
AT-X PRO SD 11-16/2.8 (IF) DX (Ver.15)
Manual Focus Only
The following lenses have been tested with previous firmware versions with manual focus, aperture control, image stabilization (if applicable) and EXIF support. Autofocus is supported only for those lenses marked with an asterisk (*) on NEX-5R/6
Canon EF primes
EF 14/2.8L (mark I)
EF 20/2.8 USM*
EF 24/1.4L USM (mark I)
EF 24/2.8 (old version, non-IS)
EF 50/1.4 USM
EF 50/1.8 II
MP-E 65/2.8 macro
EF 85/1.2L (mark I)
EF 400/5.6L USM
Canon EF zooms
EF 24-70/2.8L (mark I)
EF 24-105/4L IS USM*
EF 28-70/3.5-4.5 II
Contax N modified by Conurus
Makro-Sonnar 100/2.8 (Ver.21)
Sigma (full frame)
24-70/2.8 EX HSM
24-70/2.8 EX DG HSM
50/1.4 DG HSM (Ver.17)*
50/2.8 DG Macro
70-200/2.8 EX DG Macro HSM
12-24/4.5-5.6 EX ASPH
17-35/2.8-4 EX HSM ASPH
18-125/3.5-5.6 DC OS HSM
30/1.4 EX DC HSM new version (Ver.17)
SP 70-200/2.8 Di LD A001
AT-X PRO 28-70/2.8
This Smart Adapter is also compatible with fully manual lenses which have no electrical contacts.