PHY 2020 Lecture Notes - Lecture 45: Telephoto Lens, Ciliary Muscle, Optical Instrument
Document Summary
To see the eye as an optical instrument. A movable lens to focus the image onto a fixed location: 2. A recording media (charge-coupled device ccd or old school chemical film: 3. A shutter to control the exposure time of light: 4. A aperture that controls the amount of light that shines on the recording media. The opening of the aperture is measured in f-numbers or f-stops. The adjust for different object distances, the image distance is changed by moving the lens in or out. The lens forms an inverted, usually reduced, real image, in the plane of the film or ccd array. Changing the diameter by a factor of 2 changes the intensity by a factor of 4. The choice of focal length for a camera depends on the size of the film (or detector array) and the desired angle (or field of view). Eyeball optics and electro-chemistry turns light into images.
