Egami, the Japanese photography blog has uncovered a Canon patent, showing an optional image stabilization unit that is external to a lens, without changing its focal length.
Patent Publication No. 2015-28555 (Google Translated)
- Published 2015.2.12
- Filing date 2013.7.30
Example 1a (master lens only)
- Focal length 392.50
- F-number 2.92
- Half angle of 3.16
- Image height 21.64
- Overall length of the lens 379.64
- BF 41.57
- Effective diameter of the front lens 135.72mm
- Lens configuration 8 groups nine
Example 1b (anti-vibration converter mounted state)
- Focal length 392.50
- F-number 2.92
- Half angle of 3.16
- Image height 21.64
- Overall length of the lens 379.64
- BF 41.56
- Effective diameter of the front lens 135.72mm
- Lens construction 12 groups 15 sheets
Canon Patent
- 3-group configuration of positive and negative positive
- Inner focus (the second group)
- The anti-vibration converter can be inserted on the object side of the third group
