Construction:Both Lens and Camera Mount ends: Brass and Plated with Chromium Lens Wider:0.71x
・Increase maximum aperture by 1 stop ・Increase MTF ・Makes lens 0.71x wide ・The tripod foot is detachable and compatible with Arca Swiss Markins Photo camball heads. ・Both camera-side and lens-side of the adapter are made of brass precision-machined and plated with chromium ・Satin surface finish - just like your OEM lens and camera mounts ・Precise fit and solid connection - lens has no play gap or wiggling when mounted on adapter and no adjustments are required to fit your lens ・Designed to reach infinity focus while maintaining the correct registration distance required to maintain optical quality of CRC lenses or lenses with floating elements
Metabones Speed Booster mounts between a mirrorless camera and a SLR lens. It increases maximum aperture by 1 stop (hence its name) increases MTF and has a focal length multiplier of 0.71x. For example the Canon EF 85mm f/1.2L II lens becomes a 59mm f/0.9 lens on a Sony NEX camera with increased sharpness. The faster F-stop allows for shallow depth-of-field and a lower ISO setting for decreased noise.
Speed Booster is also particularly pertinent to ultra-wide-angle SLR lenses. The combined focal length multiplier of Speed Booster and an APS-C mirrorless camera is approximately 1.09x making the combination almost ''full-frame''. Full-frame ultra-wide-angle SLR lenses largely retain their angle-of-view on an APS-C mirrorless camera when Speed Booster is used.
The optics of Speed Booster is designed by Brian Caldwell PhD a veteran of highly-corrected lens designs such as the Coastal Optics 60mm f/4 UV-VIS-IR APO Macro lens with exemplary MTF performance (focusing done with visible light requires no correction whatsoever for the full spectrum from UV to IR).
Remark: Super telephotos such as the Telyt 560/5.6 may vignette at the corners.
The following lenses require modification in order to fit on the Speed Booster. &bull Super-Elmar-R 15mm &bull Elmarit R 28/2.8 &bull Elmarit R 35/2.8 &bull Summicron R 50/2