Optical imaging methods play a key role in many fields of science, engineering and in a huge number of everyday applications. FOI 2013 focuses on the most relevant and most challenging of these techniques, with the purpose of advancing the state-of-the-art in domains where the fundamental limits of imaging performance have not yet been achieved. By combining novel physical detection principles, advanced sensor chip and electronic circuit design, new optical imaging methods, mathematical algorithms for image reconstruction and physical techniques to improve image resolution, the frontiers of optical imaging are further pushed back.