The application of a light-field camera based on an overlapped square aperture micro-lens array (MLA) is reported. The location and direction of the incident light rays are recorded and reconstructed with a large depth of field by this imaging system. The optimized square MLA for light-field imaging, which increases the fill factor and utilization efficiency of the image sensor, is proposed. The array is fabricated by ultra-precision machining and micro-injection molding, which is economical and ensures that the array remains in high accuracy and consistency. Finally, a light-field imaging system is built with lens groups, an MLA, and an adjustable square stop. A comparative study of the field in-depth and super-resolution image is conducted. The experimental results show that the system significantly increases the range of the depth of the field. The reconstructed image is also enhanced with higher resolution and clarity.