Photographers usually know how to create depth impression of certain artistic sense or taste in the process of flattening objects in a three-dimensional space. To understand the effects of such photographic techniques determining the effectiveness of depth cues in a picture-taking scene, two experiments were performed mainly focused on the effects of manipulating aperture and focal length of lens on the depth impression of a photograph. Depth impression increases when the aperture size is made larger resulting in shallower depth of field. When the focal length of lens becomes longer making the discrepancy of relative size among subjects smaller, the depth impression decreases. A review on the historical trends of photography style was presented from the points of viewer`s perceptual responses that could be implied by the results of current study on photographic techniques for expressing depth.