By: Kelsey Zdebski, Kevin McGraw, Casey Repasy, Brenton Pedersen, Jordan Ledbetter

CAMERAS;HOW DO THEY WORK?

THE BASICS; HOW DOES A CAMERA WORK?

• The lens within the structure of the camera bends the light that the camera allows in to focus it all on one point.

• All lenses in cameras are spherical, so the image is not distorted.

• Light that is emitted from everywhere when a picture is being taken (ie – a candle, overhead lights, backlights, or spotlights) are diffusing in all directions, however, when a camera snaps a picture, it converges all of the light to focus it onto one spot producing a real image of whatever is being photographed.

THE IMPORTANCE OF FOCUS

• Focusing the camera (whether on auto focus or manually) is a huge part of taking a clear photograph.

• There is a focal point within the camera in which the image will only come out clear. Auto focus automatically moves the lenses within a camera forwards and backwards until it detects a clear image. Manually, you would have to turn the extra lens from the outside and make a good decision as to where the image is focused the clearest.

• If you are in front of the focal point or behind it the image will come out blurry

LENSES AND HISTORY • The first permanent image was

produced in 1826 by Joseph N. Niepce in France using a pin-hole camera.

• By 1839, cameras were being commercially manufactured based on the camera design by Giroux Daguerre, and a lens design by Parisian optician and instrument-maker, Charles Chevalier.

• The lens was a fifteen-inch achromatic lens and produced an image 167 x 216 mm. The use of lenses solved the problem with pin-holes, as a lens would ideally have the same projection yet gather more light.

• Lenses with an aperture to control the amount of light allowed in, and thereby control the focal distance of the lens, were introduced the same year. Cameras in subsequent years almost universally used lenses, with the exception of the American camera invented by Alexander Wolcott in 1840, which used mirrors not unlike telescopes.

CONTINUED …

• Cameras continued to evolve, as did the lenses, but due to the nature of light and how it interacts with lenses little more application could be found for lenses in cameras aside from distorting affects like the fish-eye lens

• Advancements in manufacturing processes allowed for lenses to be produced for a myriad of devices, from microscopes and telescopes to corrective contact lenses, all based on the elementary interaction of light passing between different mediums.

HOW DO CAMERAS & LENSES RELATE TO CLASS?• Camera lenses have a direct

correlation to what we have already learned in class.

• Camera lenses relate to focal length, focal point, and how images turn out in the end. We spent two days of class going over all of this material.

• The distance from the surface of the lens of the camera to the focus point is called the focal length. Most cameras are named by their focal lengths.

• There are many different types of camera lenses. Zoom lenses have multiple focal points which give them the ability to focus at different focal points.

OTHER DEVICES THAT EMPLOY THE SAME TECHNOLOGY

• Telescopes like the Hubble work similarly to the average camera, but on a much larger scale. They use curved mirrors instead of lenses because lenses of the required size would refract the image too much. Because the colors naturally bend at different angles, this would be impossible to focus.

• Cell phone cameras also differ from traditional ones. Cheaper ones use fixed-focus lenses, which are much cheaper and have no moving parts. They come with the disadvantage of much-reduced picture quality. Nicer phones have traditional motorized lenses, but they are usually housed within the phone’s body to prevent damage.

• Projectors are effectively the opposite of cameras. Instead of recording light, they produce light for humans to see. However, they also require lenses and focusing systems to both magnify the image and ensure it is clear on screens of different distances from the projector.

WHAT NEW INSIGHT DOES THE TOPIC OF CAMERAS PROVIDE? • We have learned how an extremely common, almost everyday

device that most of us use, works, and now have the knowledge to explain it in our own words

• We have directly connected it to what we are learning in class

• How the camera works was broken down and we learned about the parts, most importantly the lenses

• Discovered other devices that employ the same technology

• Learned a little history of the camera and lenses

SOURCES • Harris, Tom. "How Cameras Work" 21 March 2001.

HowStuffWorks.com. <http://electronics.howstuffworks.com/camera.htm> 30 November 2011.

• http://texas4-h.tamu.edu/library/files/volunteer_conference_photography_videography_3_evolution_of_camera.pdf

• http://www.cs.cmu.edu/afs/cs/academic/class/15462-f09/www/lec/lec4.pdf