Pentax / Ricoh filed a patent to correct focus shift caused by infrared light. In the patent we can clearly see that Rioch is working on 2nd IR (infrared) AF (Auto Focus) Sensor for correcting the Focus shift when the Phase AF sensor fails to do the correct Job in absence of visible light (In a situation when only IF is present).
Description, self-interpretation of the patent literature
- Patent Publication No. 2015-172640
- Published 2015.10.1
- Filing date 2014.3.1
- Ricoh patents
- AF sensor has a spectral sensitivity in the visible light to infrared light
- AE sensor has a spectral sensitivity in the visible light
- IR sensor has a spectral sensitivity characteristics to infrared light
- Based on the signal ratio of the AE sensor and the IR sensor, to correct the focal shift due to chromatic aberration of infrared light
See more Ricoh Patent
source – egami
