The ULTRA is featuring a new optical design incorporating ultra-high index tanatalum-based optical glass to achieve extraordinary optical performance with improved corner sharpness, distortion and reduced vignetting.
The ULTRA (like its original model) will turn any APS-C sensor into an equivalent full frame one with 1 stop gain in brightness.
Here are the key features (taken from metabones press release):
- Increase maximum aperture by 1 stop.
- Increase MTF.
- Makes lens 0.71x wider.
- Advanced 5-element/4-group optical design incorporating ultra-high index tanatalum-based optical glass 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.
- High performance 32-bit processor and efficient switched-mode power supply.
- The tripod foot is detachable and compatible with Arca Swiss, Markins, Photo Clam ball heads.