The Canon EF 400mm f/4 DO IS II features diffractive optics to ensure a portable build, making this a great choice for safari or other photo-centered trips. Here are some of the top traits of this super-tele:

• Gapless dual-layer diffractive optics for a reduction in chromatic and spherical aberrations as well a compact and lightweight overall form factor.
  
• Sub Wavelength coatings to control lens flare and ghosting for greater contrast and color fidelity.
  
• Optical Image Stabilizer to minimize the appearance of camera shake by up to four shutter speed stops when shooting handheld or in low light.
  
• Optimized focusing algorithms and a high-speed CPU.
  
• Focus Limiter switch to constrain the focusing to three different ranges for faster performance.
  
• Power Focus setting to electronically and smoothly adjust your focus position to suit video recording.
  

  
  At under 5 lbs, this lens is very lightweight for its focal length and aperture range. Its versatile settings make it suitable for a variety of shooting applications, including wildlife and sports.