The Speed Booster Ultra 0.71x Cine Adapter from Metabones is designed for Contax/Yashica-mount lens to be used with the APS-C Crop mode in full frame RF-mount cameras and has a magnification of 0.71x, effectively reducing crop factor from 1.5x to 1.07x. The ULTRA design makes very effective use of exotic materials at the furthest limit of glass-making technology and, as a result, is well corrected for use with virtually all full-frame SLR lenses regardless of exit pupil distance. High-speed fixed focal length lenses such as a 50mm f/1.2 will be transformed to a 35.5mm f/0.9 lens with excellent contrast and resolution from the center all the way to the edges of the image.
This adapter is a mechanical adapter. It does not support electronic aperture control, AF, and EXIF.
Rubber gasket protects the RF-mount connection from dust and moisture.
Both camera-side and lens-side of the adapter are made of brass, precision-machined, and plated with chromium.
It features a satin surface finish, like your OEM lens and camera mounts.
The adapter is designed to reach infinity focus while maintaining the correct registration distance required to maintain optical quality of CRC lenses or lenses with floating elements.
Precise fit and solid connection: The lens has no play, gap, or wiggling when mounted on adapter and no adjustments are required to fit your lens.
Advanced 5-element / 4-group optical design incorporating ultra-high index tantalum-based optical glass.
It makes lens appear 0.71x wider.
It increases the lens' maximum aperture by 1 stop.
The Zeiss Distagon T* 15mm f/3.5 has a protruding rear element and may not be compatible with or may require modification to fit this Speed Booster.