Canon applied for a patent about a telephoto lens 300mm F4. It realizes high-performance shake revision by using an electrooptic device.
Patent Details
- Patent Publication No. 2011-27864
- published 2011/02/10
- filled 2009/07/23
- Embodiment 1
- focal distance f=294.00mm
- Fno=4.14
- angle of view 8.24 degrees
- image circle 43.28mm
- lens length 245.03mm
- back focus 86.14mm
- The camera shake:
- The shake by a human is around 0.1-10Hz (low frequency).
- The shake by a tripod is around 4-35Hz.
- The shake by an in-vehicle camera is several Hz – around several hundred Hz (high frequency).
- The conventional camera shake revision cannot revise a shake of the high frequency.
- Because the shake revision revise a shake by mechanical movement.
- The electro-optic effect supports movement of 100Hz or more kHz.
- Canon’s patent:
- It is revise a shake of the high frequency.
- It adopts an electrooptic device.
- The device changes a refractive index of the lens by an electric field.
Via Egami
