This paper presents an optimal image acquisition methodology by replacing the traditional birefringent filter
with slight out-of-focus blur generated by the camera lens. Since many cameras already have adjustable lenses
and auto-focus systems, our method can exploit existing hardware by simply changing the focusing strategy.
During the image acquisition, the optimal defocus setting is automatically adapted to the power spectrum of
the scene which is evaluated by a generic autocorrelation model. A criterion to estimate reconstruction errors
without the baseband knowledge of the scene is developed in the paper. This metric helps the camera to choose
the optimal focus settings. An optimal Wiener filter then recovers the captured scene and yields sharper images
with reduced aliasing. The numerical and visual results show that our method is superior to current acquisition
methods used by most digital cameras.