Physics
Cameras
Cameras are devices that capture and record images by focusing light onto a photosensitive surface. They operate based on the principles of optics, utilizing lenses to form an image of the scene being photographed. In physics, cameras are studied in relation to the behavior of light, image formation, and the properties of lenses and mirrors.
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3 Key excerpts on "Cameras"
eBook - PDFHow Things Work
The Physics of Everyday Life
- Louis A. Bloomfield(Author)
- 2016(Publication Date)
- Wiley(Publisher)
For the moment, we’ll use it to cast the image of a window onto a wall. Take a magnifying glass to a room with a bright window and turn off the lights. Hold the magnifying glass near the wall opposite the window and move the glass ACTIVE LEARNING EXPERIMENTS 392 14 Optics and Electronics Courtesy Lou Bloomfield Cameras 393 Chapter Itinerary This process of bringing light together to form a small spot or an image of a distant object is a common theme in optics. Repre- senting information as charge and then storing, manipulating, and using that information is typical of electronics. In this chapter, we’ll examine a number of systems that are based on these sorts of manipulation of light and charge: (1) Cameras, (2) optical recording and communication, and (3) audio players. In Cameras, we see how lenses bend light to form images and how those images are used to create photographs. In Optical Recording and Communication, we explore the roles of lasers in optics while investigating several novel optical effects. In Audio Players, we see how a small assortment of basic electronic com- ponents is brought together to build a computer and an audio amplifier, and how those two devices have been merged together into a single unit so that you can listen to thousands of songs as you lounge on the beach. For additional preview information, turn to the Chapter Summary and Important Laws and Equa- tions at the end of the chapter. toward or away from the wall until you see a window- shaped pattern of light appear on the wall. Once that pattern is visible, carefully adjust the magnifying glass’s orientation and distance from the wall to obtain the sharp- est image of the window. You’ll probably also see images of objects outside that window, but you’ll have to move the magnifying glass to sharpen those images.
eBook - PDFOptical Imaging and Photography
Introduction to Science and Technology of Optics, Sensors and Systems
- Ulrich Teubner, Hans Josef Brückner(Authors)
- 2019(Publication Date)
- De Gruyter(Publisher)
2 Basic concepts of photography and still Cameras In order to understand the complexity and details of modern technical systems it is always helpful to have a look at the historical evolution of them. The purpose of the present book is the consideration of optical systems. Typical representatives for them are still Cameras. In the following we give a short survey of them as well as some as-pects of how they evolved with time. As for the term still Cameras we only focus on the fact of capturing a photograph or an image in general, and leave all aspects of movie Cameras out of consideration. However, it should be noted that from a historical point of view, the driving force behind the development of still Cameras and their lenses at the beginning of the 20 th century was the emerging cinema market. The standard film gauge for motion picture production at that time became the 35 mm format developed by Eastman Kodak. During movie production still Cameras for taking photos of scenes were needed. This led to the development of 35 mm Cameras where the first commer-cially successful type was produced by Leica. In the following we will give some ex-amples of Cameras with different sensors and formats. The 35 mm format, however, is of special importance and will always be the reference for comparison. The basic prin-ciple for all cases that we consider is the imaging of an object in the 3D-object space to the 2D-image plane. 2.1 Pinhole camera The simplest type of camera is the pinhole camera. Its principle has been known since the ancient Greek world, and the “camera obscura” was used often in the Middle Ages to draw pictures of objects in the real world (Figure 2.1a). They were available in vari-ous sizes, even large enough for a painter to be inside and redraw images of projected scenery. Its name “camera obscura” is the origin of the term camera, which we use for modern imaging systems.
eBook - PDF- Barbara Ryden, Bradley M. Peterson(Authors)
- 2020(Publication Date)
- Cambridge University Press(Publisher)
6 Astronomical Detection of Light As the previous chapter revealed, there is a wealth of information to be gained from observing the stars. In particular, spectroscopy of stars yields temperatures, elemental abundances, stellar rotation rates, and magnetic field strengths, among other information. While stars are intrinsically luminous, they are (except for the Sun) at extremely large distances, and hence appear to be very faint. The challenge facing astronomers over the centuries has been to collect the faint light from distant stars and other astronomical objects, and preserve and analyze the information it contains. Large telescopes and sophisticated instrumentation are required. 6.1 THE TELESCOPE AS A CAMERA In many ways, a telescope and its associated instrumentation can be thought of as a camera, albeit one with a very large and unwieldy telephoto lens. A review of how Cameras work will thus be useful for understanding the basics of imaging science. The word “camera” is the Latin word for “room,” and is a shortening of the term “camera obscura,” or “darkened room.” A camera obscura, the earliest and simplest of all Cameras, was an unlit room with a tiny hole cut in one wall; Figure 6.1 is an illustration of a camera obscura from the sixteenth century, before the invention of the telescope. Because the hole in the wall is small, only light rays headed in a specific direction can reach the far wall of the room. Thus, there is a one-to-one mapping between points on the object (the source of light) and the image. A compact version of the camera obscura is the pinhole camera (Figure 6.2), an opaque box with a tiny pinhole in the middle of one wall. If a permanent record of the projected image is required, an electronic detector or a piece of photographic film can be placed on the wall where the image is located. From Figure 6.2, we see that the image is inverted, and its size is proportional to the length F of the box, called the focal length.
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