Science of photography

Source: Wikipedia. Pages: 117. Chapters: Depth of field, F-number, Gamma correction, Aperture, Red-eye effect, Focal length, Exposure, Circle of confusion, Shutter speed, Bokeh, Printer point, Film speed, Angle of view, Tapetum lucidum, Motion blur, Exposure value, Scheimpflug principle, Reciprocity, Cardinal point, Hyperfocal distance, Perspective distortion, Photographic processing, Crop factor, Latent image, Solarisation, Lens flare, Lens speed, Tilted plane focus, Photograph conservation, Print permanence, Signal to noise ratio, Vignetting, Depth of focus, Reflector, Entrance pupil, Field of view, Film grain, Headroom, Orb, Sensitometry, Acutance, Zeiss formula, Flash blindness, Fogging, Clipping, 35 mm equivalent focal length, Soft focus, Light value, Purple fringing, Photograph stability, Fine grain master positive, Photographic emulsion, Superadditive developer, Middle gray, Available light, Colour cast, Exposure range, Actinic light, Jones diagram, Exposure latitude, Shadow noise, Photographic quantity, Lighting ratio, Petzval field curvature, Highlight headroom, Mackie line, Sensitivity speck, Critical focus, Eberhard effect, Infinity focus, Coverage, Archival image, Nadir line. Excerpt: In optics, particularly as it relates to film and photography, depth of field (DOF) is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image. Although a lens can precisely focus at only one distance at a time, the decrease in sharpness is gradual on each side of the focused distance, so that within the DOF, the unsharpness is imperceptible under normal viewing conditions. In some cases, it may be desirable to have the entire image sharp, and a large DOF is appropriate. In other cases, a small DOF may be more effective, emphasizing the subject while de-emphasizing the foreground and background. In cinematography, a large DOF is often called deep focus, and a small DOF is often called shallow focus. The DOF is determined by the camera-to-subject distance, the lens focal length, the lens f-number, and the format size or circle of confusion criterion. For a given format size, at moderate subject distances, DOF is approximately determined by the subject magnification and the lens f-number. For a given f-number, increasing the magnification, either by moving closer to the subject or using a lens of greater focal length, decreases the DOF; decreasing magnification increases DOF. For a given subject magnification, increasing the f-number (decreasing the aperture diameter) increases the DOF; decreasing f-number decreases DOF. When the "same picture" is taken in two different format sizes from the same distance at the same f-number with lenses that give the same angle of view, and the final images (e.g., in prints, or on a projection screen or electronic display) are the same size, the smaller format has greater DOF. Many small-format digital SLR camera systems allow using many of the same lenses on both full-frame and "cropped format" cameras. If the subject distance is adjusted to provide the same field of view at the subject, at the same f-number and final-image size, the smaller format has greater DOF, as with the "same