One 'embodiment' of the concept covered in the patent makes use of lens IS [104], electronic IS [118] and an 'image capture shake correction control unit' [622] connected to the sensor.

Canon has patented a method for improving its dual IS system during longer exposures. In doing so, the patent explicitly mentions the idea of triple IS, which makes use of in-body image stabilization.

The patent itself relates to the challenges of combining lens and digital image stabilization. At present Canon uses optical (lens-based) stabilization to compensate for small, fast, high-frequency movements such as the movement of a vehicle or rapid hand shake, and then uses electronic stabilization (adjusting the crop region of the sensor to stay aligned with the subject) for low-frequency movements.

The patent itself focused on balancing the roles played by the optical and electronic stabilization systems, and varying it depending on shutter speed.

The problem is that, during long exposures this electronic stabilization isn't effective: the camera continues to move slowly around the subject but the camera can't adjust which region of the sensor it uses, mid-exposure: so you still experience blur. This patent gets around this by assessing the current shutter speed and handing-off more responsibility for low-frequency movement from the electronic IS system to the lens IS system.

What makes it more interesting (beyond the insight that Canon is constantly trying to improve these things), is that the patent is phrased to ensure it also applies to a triple IS system that uses optical, electronic and sensor-shift stabilization.

Canon has already said it's working on a combined optical and in-body IS system that will work together. This patent suggests its engineers have had this possibility in mind for some time.