List of incompatible lenses:

•     Nikkor 2.1cm f4
•     20/2.8 AI-S

Sharper corners, less distortion, reduced vignetting

Optical design: advanced 5-element/4-group optical design incorporating ultra-high index tanatalum-based optical glass to achieve extraordinary optical performance with improved corner sharpness, distortion and reduced vignetting.

The Speed Booster ULTRA has a magnification of 0.71x, and so it effectively reduces the crop factor of mirrorless cameras with DX-sized sensors, such as Sony E-mount and Fuji X-mount cameras, from 1.5x to 1.07x. However, the 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 fullframe 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 24-70mm f/2.8 and 70-200mm f/2.8 zooms by Canon and Nikon to produce 17-50mm f/2.0 and 50-142mm f/2.0 high-speed zooms, respectively. Similarly, high-speed fixed focal length lenses such as a 50mm f/1.2 will be transformed into a 35.5mm f/0.9 lens with excellent contrast and resolution from the center all the way to the edges of the image.

Note: This Speed Booster ULTRA is NOT fully compatible with full-frame Sony A7, A7R and A7S. When the Speed Booster® are used with Sony A7, A7R or A7S the camera is required to be used in the "APS-C Size Capture" mode.

Tips: Before mounting your lens to the adaptor, please make sure that the f-stop of aperture ring on the adaptor is turned to "7" (i.e. mounting your lens to the adaptor while only the aperture ring in the adaptor is full closed.).

Remark: This mount is manual aperture control. It does NOT support electronic aperture control.

Disclaimer: we are NOT licensed, approved or endorsed by Sony or Nikon