Canon EF - E-mount SpeedBooster

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  • Increase maximum aperture by 1 stop.
  • Increase MTF.
  • Makes lens 0.71x wider.
  • Optics designed by Caldwell Photographic in the USA (patent pending).
  • Electronic integration of aperture diaphragm, controlled by or from the camera body.
  • Partial autofocus support for late-model (post-2006) Canon-brand lenses.
  • Powered by camera body. No external power source required.
  • The tripod foot is detachable and compatible with Arca Swiss, Markins, Photo cam ball heads.
  • High performance 32-bit processor and efficient switched-mode power supply.

Kit includes



  • EF lenses
  • 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 1)
  • Auto magnify (see note 1)
  • Contax N mount lenses modified to Canon EF by Conurus (see note 2)
  • Contax 645 NAM-1 adapter modified to Canon EF by Conurus (see note 2)
  • Sigma, Tamron and Tokina lenses in Canon EF mount (see note 3)
  • Manual focus lenses adapted to Canon EF mount ('chipped' or 'AF confirm' adapters are not supported)


  • Requires lenses supporting distance information.
  • Autofocus disabled for Contax N and Contax 645 lenses.
  • 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.
  • This Speed Booster™ is designed to cover an APS-C image circle which is not big enough to cover a full-size 36mm x 24mm sensor.
  • Sony NEX cameras cannot display aperture values beyond f/1.0. If a f/1.2 Canon EF lens is used with the Speed Booster™, the resulting aperture is f/0.9 but the camera body displays f/1.0.

Technical Specifications

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£25.00 per day

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