[Patent] Canon 24-70mm f/2.8 Image Stabilized Lens

Egami (machine translated) found a new Canon patent for a 24-70mm f/2.8 lens with Image Stabilization. They suggest, correctly in my opinion, that Canon has to react to the release of the Tamron AF 24-70mm f/2.8 SP Di USD VC which has image stabilization (called VC, Vibration Compensation by Tamron).

• Patent Publication No. 2012-123156
  • 2012.6.28 Release Date
  • 2010.12.8 filing date
• Example 1
  • Zoom ratio 2.46
  • 68.99mm – f = 28.00 focal length
  • Fno. 2.88
  • 17.41 deg – 37.69 half angle of view.
  • Image height 21.64mm
  • 222.38mm – 192.25 full-length lens
  • BF 39.98 – 53.68
  • Effective diameter 74.47mm ball before
  • Effective diameter aperture 31.23mm
  • 19 sheets 12 group lens configuration
  • Three three aspherical surface
  • 2 UD glass sheet
• Example 2
  • Zoom ratio 2.86
  • 68.70 – f = 24.00 focal length
  • Fno. 2.88
  • 17.48 deg – 42.03 half angle of view.
  • Image height 21.64mm
  • 224.86mm – 191.93 full-length lens
  • BF 39.85 – 55.68mm
  • Effective diameter 77.29mm ball before
  • Effective diameter aperture 32.58mm
  • Lens Construction 12 group 21 sheets
  • Three three aspherical surface
  • 2 UD glass sheet
• Five-group zoom positive and negative positive positive and negative
• (For Focusing group 2) Inner Focus
• (Part 1 of the fourth lens group, anti-vibration unit is L4a) image stabilization
• Positive refractive power of the first lens group
  • The aberration can be corrected and weaken, the lens is larger
  • Difficult to correct aberration and strengthen
• The amount of movement of the second lens group and one, the first
  • Must be strengthened to reduce power and refraction, aberration correction is difficult
  • Diameter of the first lens group becomes larger and more