• 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.

PLEASE SEE NOTES FROM THE MANUFACTURERS WEBSITE 

Compatibility

Note:

1. Requires lenses supporting distance information.
2. Autofocus disabled for Contax N and Contax 645 lenses.
3. 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.
4. 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.
5. Sony NEX cameras cannot display aperture values beyond f/1.0. If a f/1.2 Canon EF lens is used with Speed Booster™, the resulting aperture is f/0.9 but the camera body displays f/1.0.
6. Some improperly-made M42 screw mount adapters may short the electronic contacts of the Speed Booster™ and cause damage to the Speed Booster™ and/or camera body.
7. Many manual focus lenses (e.g. OM 28/2.8, OM 50/1.8, Leica R 15/3.5) have rear protrusions (spikes, levers, other appendages) which would damage the optics and/or housing of Speed Booster™. They need to be modified before they can be safely used on Speed Booster™. Check and make sure there are no rear protrusions from the adapter/lens combination before using on Speed Booster. Scratches and damages caused by rear protrusions on Speed Booster™ are not covered by warranty.
8. Some telephoto lenses such as the Leica-R Telyt 560/5.6 may have significant vignetting in the corners.

Autofocus

Autofocus is supported, with the following known limitations.

• Autofocus speed is very slow and inadequate for most moving subjects. The autofocus speed is unfit for professional use for sure, and it would disappoint most enthusiasts.
• Only Canon-branded lenses introduced in or after 2006 are officially supported. Autofocus is disabled for older Canon lenses and most third-party lenses, including most Sigma, Tamron and Tokina lenses and all Contax N lenses modified by Conurus.
• On FS series (e.g. FS700, FS100), autofocus may be available only in photo mode but not in movie capture mode.
• Continuous AF is not supported.
• DMF mode (direct manual focus) is not supported.
• For non-camcorder camera bodies (e.g. NEX-7), during movie capture, if the subject moves to a different distance, half-press the shutter release button to re-activate autofocus and lock onto the subject again. Since autofocus speed is slow, there may be visible disruption in the resulting footage.
• 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 worn-out gear train with out-of-spec backlash, a faulty/worn-out distance encoder or other faulty/worn-out internal sensors.

List of lenses with autofocus support on Speed Booster™

Autofocus is DISABLED for the following lenses

Image stabilization (if supported by lens), auto aperture and EXIF work. Autofocus is supported only for those lenses marked with an asterisk (*), on NEX-5R/6, and with adapter firmware version 18 or above.

List of manual focus lenses which REQUIRE MODIFICATION to be used on Speed Booster™

Many manual focus lenses have rear protrusions (spikes, levers, other appendages) which would damage the optics and/or housing of Speed Booster™.

They need to be modified before they can be safely used on Speed Booster™. Check and make sure there are no rear protrusions from the adapter/lens combination before using on Speed Booster. Scratches and damages caused by rear protrusions or by poor quality adapters are not covered by warranty. The following is an incomplete list of lenses known to be incompatible.