{"id":11,"date":"2015-12-23T16:36:20","date_gmt":"2015-12-23T16:36:20","guid":{"rendered":"http:\/\/www.revolutionsincommunication.com\/viscomm\/?page_id=11"},"modified":"2025-02-05T15:41:23","modified_gmt":"2025-02-05T15:41:23","slug":"cameras","status":"publish","type":"page","link":"https:\/\/revolutionsincommunication.com\/viscomm\/cameras\/","title":{"rendered":"Digital Cameras"},"content":{"rendered":"

\"\"<\/a>From the dawn of photography\u00a0<\/span><\/strong> two centuries ago, all cameras have had the same five basic components:<\/p>\n

    \n
  1. A light-proof box containing …<\/li>\n
  2. … light-sensitive material, which is carefully exposed with\u00a0 <\/span>a combination of …<\/li>\n
  3. a lens, and<\/li>\n
  4. an aperture in the lens, and<\/li>\n
  5. a shutter that covers the light-sensitive material\u00a0 most of the time but opens for a fraction of a second when the shutter is released.<\/span><\/span><\/li>\n<\/ol>\n
    \n

    \u00a0 1. A light proof box <\/strong><\/p>\n

    \"\"<\/a>

    18th century illustration of a Camera Obscura. Wikimedia Commons<\/p><\/div>\n

    A light proof box is called a \u201ccamera\u201d\u00a0 <\/span>because it comes from the Latin term \u201ccamera obscura<\/a>\u201d which means \u201cdark room.\u201d\u00a0 <\/span>This\u00a0 <\/span>refers to a phenomena that has been noticed across many cultures and in many different pre-industrial eras of human experience.\u00a0 The phenomena is that a person in a room that is completely dark — except for a tiny pinhole that lets in light from the outside — will see an image from outside projected upside down on the opposite wall.<\/p>\n

    Camera housings have changed in size and shape over the years, but the main job is the same: to keep out light until it’s time to expose the light sensitive material.<\/p>\n

    2. Light sensitive material <\/strong><\/p>\n

    Since the dawn of industrial era it’s been known that certain materials are sensitive to light and have the potential to create a photographic image. The problem for early inventors is that the image would fade away. So the problem was how to \u201cfix\u201d the image.\u00a0 Thomas Wedgewood, famous for his china factory and experiments in electricity, probably came the closest in the 18th century when he discovered the light-sensitive properties of silver nitrate.<\/p>\n

    Techniques for “fixing” the light sensitive plate in a chemical bath were\u00a0 invented by French artists Joseph Niepce and Louis Daguerre in the 1820s and 1830s.\u00a0 By the summer 1839, the French Academy of Sciences bought their\u00a0 invention and published the chemical formula and procedures involving a metal plate coated with a light-sensitive gel.<\/p>\n

    \"\"<\/a>

    A Parisian couple sits still for two minutes with the help of neck braces in order to have a Daguerrotype portrait taken. The long exposure times were necessary because light sensitive materials were relatively weak at the time.\u00a0 Engraving by\u00a0Honor\u00e9 Daumier, c. 1850.<\/p><\/div>\n

    Meanwhile, English photographer Henry Fox Talbot and others contributed a variety of technological advances, including the use of glass plates and negatives that could print many copies of the original exposure.<\/p>\n

    Still, photography mostly involved portraits of people sitting very still until more flexible cameras came along.<\/p>\n

    One major\u00a0 breakthrough came in the 1870s with the development of transparent celluloid\u00a0 films that were far lighter than glass plates.\u00a0 This allowed early “film” cameras such as those pioneered by the Lumiere Brothers in France and George Eastman’s Kodak company in the US.\u00a0For about a century, photography involved film negatives printed as positives onto photo paper.\u00a0 <\/span><\/p>\n

    Another major change in technology involved digital cameras, which were developed in the 1970s and became cheap enough for popular photography in the 2000s.\u00a0 Today, the light sensitive material is a sensor plate that picks up photos and stores them as a digital image. Early systems used a CCD (charged couple device)\u00a0 sensor, while the newer systems use a CMOS sensor (Complementary metal\u2013oxide\u2013semiconductor).\u00a0<\/b> \u00a0Higher end professional cameras ($2,000+) have larger sensors (Nikon FX cameras), while smaller popular cameras tend to cost about $200 to $1,000 (Nikon DX cameras).\u00a0 \u00a0<\/span><\/p>\n

    ISO ratings<\/strong> are one way that the light sensitivity of a digital camera is rated. By 2016,\u00a0 digital cameras with an ISO rating of 25,000 and more were available, making precision low-light photography possible.<\/p>\n

    3. The Lens\u00a0 <\/span><\/strong><\/p>\n

    The primary job of lens is to focus the image on the surface of the light-sensitive material.\u00a0 A good lens will give\u00a0sharp details and rich colors without distortion.\u00a0 Focusing can be automatic (for most cameras and camera phones) or manual.<\/p>\n

    The Focal Length<\/strong> of a lens\u00a0 is the distance between the lens and the image sensor when the subject is in focus. This is expressed in millimeters ( for example,\u00a0\u00a028 mm, 50 mm, or 200 mm). If it’s a zoom lens, both the minimum and maximum are given (18\u201355 mm).<\/p>\n

    The varieties of picture angles are given here on a Nikon photography site.<\/a>\u00a0 \u00a0But basically, 50 mm is a natural field of human vision, while 400 mm would be telephoto, 18 mm would be wide angle and 10 mm would be “fish eye.”<\/p>\n

    4. Aperture\u00a0<\/strong><\/p>\n

    The aperture is located inside lens. It’s job is to control the amount of light going through the lens to the light-sensitive surface, so it can open and close in an iris-like configuration.<\/p>\n

    An aperture setting is called an f-number or “f-stop” and settings found in a ring around the lens may go from the most open\u00a0 (at around 1:1.2 or f-one-point-two)\u00a0 to the tightest (at around 1:22 or f-twenty-two).\u00a0\u00a0\u00a0<\/span><\/p>\n

    A higher f-number means sharper focus and a greater area of focus, also called depth of field<\/a>.\u00a0 But the higher number also means less light, so that means a slower shutter speed and a need for a higher ISO sensitivity.<\/p>\n

    5. Shutter\u00a0<\/strong><\/p>\n

    The shutter is the part of the camera that opens quickly to take the photo.\u00a0 A fast shutter is needed to avoid blurring, but a slower shutter may give a deliberate blurring effect.\u00a0 Speeds go from wide open or \u201cB\u201d (for \u201cbulb\u201d) up 1\/2000th<\/sup><\/span> or higher for scientific & technical work.<\/p>\n

    The slowest shutter speed that will take a sharp photo with a hand-held camera is about 1\/60th to 1\/125th of a second.\u00a0 Sports photographers typically shoot in the 1\/500th to 1\/2000th range.<\/p>\n

    6. Recording system \/ SD card\u00a0<\/strong><\/p>\n

    One part of the camera that is unique to digital cameras is the memory card that is used in DSLRs to record and transfer images.\u00a0 With photos\u00a0up to 24 MB each, it’s a good idea to get a memory card that has 32 GB or more of storage.\u00a0 \u00a0Most cards will have a Class 10 sequential writing speed.\u00a0 Look for C10 on the SD card, especially\u00a0 if you are also going to record video.\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0<\/span><\/p>\n

    Types of cameras<\/h3>\n
      \n
    • Single Lens Reflex\u00a0 (and Digital Single Lens Reflex)\u00a0 — Professional cameras that allow focusing through the lens and have aperture and shutter controls\n

      <\/a>

      SLR — Canon 1966 35 mm film camera with 125 mm lens by Alvesgaspar, Wikipedia<\/p><\/div><\/li>\n

    • Mirrorless\u00a0 — Digital cameras without through-the-lens focus but similar to DSLRs<\/li>\n
    • Camera phones —<\/a>\u00a0 \u00a0 \u00a0Introduced in 2000, found everywhere today, not professionally flexible but very handy.<\/li>\n
    • Large format —\u00a0 19th century glass plate cameras<\/a>, late 19th and early 20th large format bellows cameras for artistic and landscape work<\/li>\n<\/ul>\n

      EXPOSURE\u00a0<\/b><\/h3>\n

      The skillful combination of\u00a0 <\/span>ISO, aperture and shutter is what creates a good exposure. In most cameras, an automatic feature means you don\u2019t have to worry about it just to get a snapshot. But it is important in order to understand digital imaging.\u00a0 \u00a0 \u00a0\u00a0<\/span><\/p>\n

      Many digital cameras have semi-automatic\u00a0 “aperture priority” (AP) or “shutter priority” (SP) settings.\u00a0 AP is what you might want to use for low-light or high lighting conditions.\u00a0 SP is what you might use for action shots where you want to avoid blurring.<\/p>\n

      Shutter, aperture and ISO <\/strong>are interdependent factors in achieving a good exposure.\u00a0 \u00a0This exposure simulator, created by self-described “crazy inventor” Dima Tsvetkov<\/a>, gives an idea of how the three main elements interact.<\/p>\n