The science behind modern cameras is very complex, but, if we look at an older camera, we can see the basics needed to make it work. “SLR cameras, or single-lens reflex cameras, provide an excellent illustration of the fundamental processes of photography.” (Harris, Tom) One of the main components of a camera is the lens. The lens focuses light rays to create the image. Light rays are made up of small transverse waves. “Cameras use convex lenses to create a real image, that is, an image that looks just like the scene in front of the lens. Convex lenses converge light rays using a phenomenon called refraction. Light travels faster in air than in glass, which the lens is made of, so the angle becomes smaller when they enter the lens, and this causes the light rays to converge." (Harris, Tom) As the distance between the lens and the image increases, the light beams spread further. This causes the image to increase in size. Film is used to record the image. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay Film is the chemical part of the camera. “When the film is exposed to an image formed by the lens, it creates a chemical recording of light. This is done with light-sensitive beads, spread on a piece of plastic. These grains react with light, which forms the chemical record.” (Harris, Tom) If the film is exposed to too much or too little light, the image will be too light or too dark. To prevent this from happening, we need to control the amount of light that enters a lens. To do this, you change the size of the opening. The aperture lets light into the lens. If you reduce it, less light will be able to reach the lens and the image will not be as bright. Exposure can also be adjusted by changing the shutter speed. Digital cameras are more complicated than that, with many more moving parts and electrical components. Cameras, such as security cameras, and others allow us to capture videos and images. Security cameras allow us to capture images of criminals and catch and arrest them much easier. This is a good thing because we have less crime because of it. “Cameras are also used in medicine, to be able to see the inside of the body, without performing surgery or making large cuts in the body. These cameras can show many problems in the body, including identifying tumors or other such medical problems.” (AG, Basel) Cameras have many uses in the real world, which make people's work and lives easier. But they also have negative effects. “Cameras, like SLR cameras that use film, are harmful to the environment. They use a lot of chemicals every time the film is developed, and then those chemicals can't be used anymore. These chemicals end up in landfills or are discharged into rivers and the environment.” (Adams, Mike) Furthermore, the production of camera casing is harmful to the environment, because these cameras are made of plastic, which is made of petroleum and cannot decompose. When people are done with their camera, they throw it in the trash and it ends up staying there. “Digital cameras have a much lower environmental impact than SLR cameras. Digital cameras can be used for much longer and do not use chemicals to develop images. The photos you take are digital, so you don't have to print them and waste paper, you can simply share them.