Light field imaging and processing is one of the most potential directions in the field of computational photography. Constructing concise and efficient representations of light field is the theoretical basis and key to promote the applications of light field. Based on the depth, texture, geometry, scale, and spectrum of light field, this paper analyzes characteristics of typical light field representations, including sub-aperture image, epipolar plane image, focal stack, super-pixel, multiplane images, hypergraph, Fourier slice, Fourier disparity layer, and epipolar focus spectrum. This paper also summarizes the impacts of different representations for light field applications, such as reconstruction, depth estimation, editing and so on. Finally, the advantages, disadvantages, and potential applications of various representations are summarized.