Focal reducer by Zhongyi that reduces focal length by a 0.71x factor and gains one stop of light.
Technical Details
The Lens Turbo reduces the effective focal length by 29% (0.71x) and opens the aperture by one stop – a 50mm f/2.8 lens becomes a 35.5mm f/2.0 equivalent. The optical design is based on a modified Galilean telescope design with aspherical elements to minimize distortion and vignetting. Available variants include Canon EF to Sony E-mount, Canon EF to Fujifilm X-mount, and Canon EF to Micro Four Thirds. The mechanical construction omits electronic contacts – aperture control is manual on the lens or via aperture adapters.
History & Development
Zhongyi Optics launched the Lens Turbo in 2013 as a cost-effective alternative to Metabones' Speed Booster, which had established the Focal Reducer market a year prior. The first generation still showed significant optical weaknesses in the image corners. The Mark II version, introduced in 2015, considerably improved edge sharpness and reduced chromatic aberrations. Since 2018, Zhongyi has also offered variants for vintage lenses such as Contax/Yashica and M42 mount.
Practical Use in Film
Independent productions frequently use the Lens Turbo to employ expensive full-frame cine lenses on cost-effective Super35 cameras like the Blackmagic Pocket Cinema Camera. The adapter allows Canon L-series lenses to be used on Sony Alpha cameras, retaining the desired full-frame look. Documentarians appreciate the weight reduction compared to native full-frame setups. Disadvantages include potential sharpness loss in the image corners, increased vignetting at extreme focal lengths, and the absence of electronic lens communication.
Comparison & Alternatives
Compared to the Metabones Speed Booster, the Lens Turbo offers 80% of the optical performance at 40% of the price. Viltrox's EF-E variants integrate electronic contacts for autofocus and aperture control but do not achieve the optical quality of the Lens Turbo Mark II. Modern alternatives like the Kipon Baveyes or Commlite EF-E adapters offer similar reduction factors with improved electronics but cost significantly more. For purely manual operation, the Zhongyi Lens Turbo remains the most economical solution for semi-professional productions.