The Metabones Contax N to E-mount Speed Booster ULTRA 0.71x uses an advanced 5-element/4-group optical design by Caldwell Photographic Inc., incorporating ultra-high index tantalum-based optical glass to achieve extraordinary optical performance with improved corner sharpness, distortion and reduced vignetting. Speed Booster ULTRA has a magnification of 0.71x, effectively reducing the crop factor of APS-C cameras from 1.5x to 1.07x. The Speed Booster ULTRA design makes very effective use of exotic materials at the furthest limit of glassmaking technology, and as a result, is well corrected for use with virtually all full-frame SLR lenses regardless of exit pupil distance. Thus, the Speed Booster ULTRA performs extremely well with professional-grade f/2.8 zoom lenses such as the Carl Zeiss Vario-Sonnar T2,8/17-35. Similarly, high-speed fixed focal length lenses such as the Carl Zeiss Planar T 1,4/50 and Carl Zeiss Planar T 1,4/85 will be transformed into f/1.0 lenses with excellent contrast and resolution from the centre all the way to the edges of the image.
Like all Metabones Speed Boosters, the Speed Booster ULTRA is optimized to fully account for the camera’s filter stack located near the sensor surface. This is especially critical at the extremely large apertures made possible by Speed Booster technology. As a result of this careful optimization, the complete range of Contax N and Contax 645 lenses will function flawlessly when adapted to Sony E-mount APS-C format camera bodies. (Speed Booster ULTRA cannot be used to adapt a Contax 645 lens to a full-frame E-Mount camera such as the A9 and the A7 series.)
|Dimensions||H: 31.4 x W: 72.3 x D: 76.0 mm|
|Tripod Mount||1/4"-20 thread|
|Optical Design||5 Elements in 4 Groups|
|Lens Mount||Contax N|
|Camera Mount||Sony E|