Presentation on theme: "How does a camera work? Ksenia Bykova. Types of film cameras SLR cameras (Single Lens Reflex) SLR cameras (Single Lens Reflex) – you see the actual."— Presentation transcript:
Types of film cameras SLR cameras (Single Lens Reflex) SLR cameras (Single Lens Reflex) – you see the actual real image “Point-and-shoot” cameras “Point-and-shoot” cameras – you don’t see the real image formed by the camera lens, but you have an idea of what is in view.
Three basic elements of a film camera An optical element (the lens) A chemical element (the film) A mechanical element (the camera body itself) The most important part of camera is the lens. Let’s discuss it in more detail.
What is lens? “A lens is an optical device which affects the focusing of a light beam through refraction” ("Lens (optics)." Wikipedia. Wikimedia Foundation, 18 Nov. 2014. Web. 17 Nov. 2014.) A simple lens consists of a single piece of material, while a compound lens consists of several simple lenses (elements). Lenses are made from glass that is ground and polished to a desired shape.
The focal length The focal length of a lens is defined as the distance in mm from the optical center of the lens to the focal point. The focal length f is then given by where u is the distance between the light source and the lens, and v is the distance between the lens and the screen.
The magnification Magnification is the ratio of the image size to the object size. The greater the focal length, the higher the magnification. With, being the distance from the lens to the image, the distance from the lens to the object, the height of the image and the height of the object, the magnification can be written as:
Convex Vs. Concave lenses Convex lensConcave lens A convex lens makes objects look farther away A Concave lens makes objects look smaller and closer A convex lens is thicker in the middle than it is at its edges A concave lens is thicker at the edges than it is at the center A convex lens refracts light rays inwardA concave lens refracts light rays, spreading them outward
Types of lenses Wide-angle lenses Normal lenses Long-focus lenses Telephoto lenses Prime lenses Macro lenses Zoom lenses
Wide-angle lenses Wide-angle lenses have huge, 60+ degree angles of view, and are usually used for focusing on objects closer to the photographer. Usually wide-angle lenses have short focal lengths.
Normal lenses Normal lenses are those that most closely represent the “natural” imaging similar to what the human eye captures. These are typically between 35mm and 50mm
Long-focus lenses Long-focus lenses are the huge lenses that are used to magnify objects at great distances. They have the narrowest angle of view, and are often used to create depth of field shots and shots where background images are blurred.
Telephoto lenses Telephoto lens - an optically compressed version of the long-focus lens. Telephoto lenses are typically much shorter and may be lighter for equivalent focal length. Telephoto lenses have longer corresponding focal lengths.
Prime lenses A prime lens has no zoom – it is one focal length. The lens is manufactured precisely to provide this one length, and doesn’t have the moving pieces and mechanisms required to zoom.
Macro lenses Macro lenses have an intense level of magnification, capable of picking out the tiniest details and enhancing them to be larger than what we can see with our own eyes
Zoom lenses A zoom lens allows the photographer to vary the focal length, whereas this cannot be changed with a fixed focal length lens. “A simple zoom lens system. The three lenses of the afocal system areL 1, L 2, L 3 (from left). L 1 and L 2 can move to the left and right, changing the overall focal length of the system (see image below).” ( "Zoom Lens." Wikipedia. Wikimedia Foundation, 27 Oct. 2014. Web. 21 Nov. 2014. )
How does a film camera work? “All of these pieces work together to get the final picture: 1. Light reflects off the object being photographed. 2. This light reflects off the object in all different directions and hits the lens from different angles. 3. The lens focuses these rays of light to a point behind the focal point forming a real image. 4. The film is placed at the point where the real image is projected to. 5. The shutter temporarily moves from in front of the film and allows light to hit the film. 6. Light hits the film causing chemical reactions which "expose" the film. 7. The shutter then closes, and finally the film is advanced so an unexposed piece of film is ready for the next picture.” ("How Does A Camera Work?" How Does A Camera Work? N.p., n.d. Web. 16 Nov. 2014.)
Film camera Vs. Digital camera When film is exposed to light, the light can be appropriately dispersed while minimizing reflection, since the surface of film is not like a mirror. With digital cameras, however, strong reflection occurs when light falls on the image sensor.
Personal Insight I’m very interested in photography and cameras. Personally, this topic is very important for me, because I want to work in the film and media industry. Thanks to this project I discovered a lot of interesting and useful information which helps me understand how a camera works. For example, I learned different focal lengths and angels of view. In addition, I learned many new types of lenses in cameras.
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