Sigma patent for 400mm f/2.8 OS Sport Lens

Egami (translated) spotted an interesting patent filed by Sigma. It refers to a 400mm f/2.8, image-stabilized lens. This lens will be part of Sigma’s “Sport” line-up.

• Patent Publication No. 2015-64436
  • Published 2015.4.9
  • Filing date 2013.9.4
• Example 1
  • Focal length 390.00mm
  • Fno. 2.91
  • Total angle of view 2ω 6.29 °
  • Image height Y 21.63mm
  • Overall length of the lens 353.00mm
  • Positive, positive positive and negative negative 5-group configuration
  • Inner Focus (fourth group)
  • Anti-vibration (part of the fifth group)