Two points of light diffract through an iris, shown with T.V. camera. (RETIRED)

6C10.15 • E+10+40

NOTE: This demo is officially retired. The equipment that makes it function is no longer working. If you'd like a similar demo you can ask the staff to concoct it but we will need additional time to create a new version with the equipment available. Resolution of a Lens: 2 points of light diffract thru iris & lens; shown on monitor. The 'resolution' of a lens is the measure of the ability to produce distinct images of two point objects close together. The resolution is affected by two things: the aberration of the lens, and diffraction of light. When two point objects are very close, their diffraction patterns overlap, and a point is reached where it is not possible to discern whether there are two images or a single image. (Distance between pinholes and iris #1 is 250 cm; between iris #1 and lens is 5.5 cm; and between iris #2 and microscope objective is 18 cm.) (Note: see file-cabinet folder for more detailed set-up notes.) In this setup, light shines through two pinholes (.5 mm diameter, 1 mm apart), and then through iris #1, a telephoto lens, iris #2, and then through a x4 microscope objective and is sensed by a television camera. Closing down iris #1 sharpens the image, until the limit of resolution is reached at an opening of about 2 mm.