Motion invariance and custom blur from lens motion

We demonstrate that image stabilizing hardware included in many camera lenses can be used to implement motion invariance and custom blur effects. Motion invariance is intended to capture images where objects within a range of velocities appear defocused with the same point spread function, obviating the need for blur estimation in advance of de-blurring. We show that the necessary parabolic motion can be implemented with stabilizing lens motion, but that the range of velocities to which capture is invariant decreases with increasing exposure time. We also show that, when that range is expanded through increased lens displacement, lens motion becomes less repeatable. In addition to motion invariance, we demonstrate that stabilizing lens motion can be used to design custom defocus kernels for aesthetic purposes, and can replace lens accessories.