Lens Free Imager (LFI) is a microscope. LFI does not require any optical lens because LFI reconstructs the image of the sample from the computational process on the image of its interference waves, which are created as leaser light hits the surface of sample and are captured by the CMOS sensor of LFI. Unlike optical microscope, the structure of LFI is simple and LFI does not need to make focus on the sample. Therefore, LFI is capable of taking an image of sample quicker and has the wider actual field of view than existing optical microscopes. Also, similar to phase-contrast microscopes, LFI can capture images of transparent samples such as living cells without applying any invasive preparation.