There is pressing need for 3D imaging technology in many areas. A number of lightfield camera designs are proposed using single image sensor. However, due to the limited size of image sensor chip and optical design, the disparity of the lightfield captured using single sensor camera systems is very small. Stanford group pioneered an implementation of lightfield capture systems using camera array. But, since the camera array often employs discrete imaging sensors and associated optics, the coverage image area for 3D reconstruction is limited. We propose a novel optical design approach that customizes the design for each optical channel to maximize the image quality, coverage area, among other design targets. We then integrate the optical design of all imaging channels into a single monolithic piece with compact structure, high reliability and assembly precision. As a result, the captured light field images from all imaging channels have the same object size with uniform image quality, thus greatly improve the quality of 3D light field reconstruction.