Typically, when we capture an image, at least three objects are involved:
- The subject is something we want to capture in the image. Typically, it is an object that reflects light, and we want this object to appear in focus (sharp) in the image.
- The lens transmits light and focuses any reflected light from the focal plane onto the image plane. The focal plane is a circular slice of space that includes the subject (as defined previously). The image plane is a circular slice of space that includes the image sensor (as defined later). Typically, these planes are perpendicular to the lens's main (lengthwise) axis. The lens has an optical center, which is the point where incoming light from the focal plane ...
