Light field rendering is an approach to synthesize virtual views of a scene from a set of original images. When minimizing the number of images for rendering, the light field may become under-sampled, leading to aliasing artifacts. To render an under-sampled light field in high quality and without aliasing artifacts is a challenge. We present a light field rendering algorithm with region-based focus to create all-in-focus virtual views. Our algorithm was compared to: (a) ground truth images and (b) a state-of-the-art technique for rendering under-sampled light fields. Extensive rendering experiments confirm that our algorithm provides visible quality improvement, quantified as about 10% RMSE reduction. However, the subjective improvement is larger and it produces images comparable to the ground truth. This algorithm contributes to practical applications of light field rendering, such as image generation in stereoscopic displays and Free-Viewpoint Video (FVV).