Monday, August 16, 2010

Understand Camera Lenses

Did you ever wonder exactly how the lens of a camera works? It's a tricky-looking device, and it's pretty amazing how you can point the front of your camera at an image and get the exact duplicate of that image inside your camera. A camera lens is actually much like the lens of the human eye, which requires light to see the images produced in front of it. The pupil of the human eye can dilate open and shut to adjust the amount of light it needs to process an image. This is the same with a camera lens. Unlike the eye, there are a variety of millimeters of lenses for a camera, and the longer the lens, the closer the picture. Here are some details to help you understand and get the bigger picture.








Instructions








1. Look inside the camera lens from the front. The lens of a camera works much like the human eye, which has a round, thin, transparent membrane on the surface of the front of the eyeball. This membrane is a lens that focuses an image onto the retina at the back of the eye. In a camera lens, a shaped glass (like a magnifying glass) on the front of the camera lens focuses an image of whatever is before it onto a strip of photographic film or a digital chip inside the camera where the image is recorded.


2. Check out your surroundings using your eyes first. The lens that most approximates the view of a human eye is usually between 30mm and 36mm. Our eyes don't see in extreme telephoto or in an extremely wide angle without the help of a camera. When you look around yourself each day in your daily life, this will give you an idea of what a 35 millimeter lens on a camera sees.


3. Look in a mirror and watch your pupil contract when light hits it. A circular iris built into the lens also opens wider or smaller (like the pupil in your eye) to admit more or less light, depending on how bright the image is. When your camera is set to automatic exposure, if you're taking a picture outside on a bright day, the iris will close down to allow only a pinpoint of light in order to record the picture accurately. If you're taking a picture indoors at night, the iris will be open wide to allow as much light as possible into the camera, and your camera will require the use of a flash to fill in the extra light required. If you have no flash, you'll find that your picture records black or dark.


4. Study the differences between wide angle or telephoto lenses. Camera lenses come in different focal lengths. The lower the number, the wider the field of view. In 35mm camera photography for example, a 15mm lens is very wide angle (perfect for use in a landscape photo) while a 100mm lens provides a narrow telephoto view, like looking through a telescope. When photographing the face, the longer the lens, the more beautiful the photo, since the face will be large and in focus while the background fuzzes out into blurry and pretty shapes and colors. Photographing the face with a wide-angle lens will distort the image of the face, stretching the features lengthwise to the sides and shrinking the vertical.


5. Experiment with an adjustable zoom lens. Zoom lenses can change their focal length from very wide to extreme telephoto. Even the most inexpensive digital camera these days will have a moderate zoom lens and a flash built in to give the photographer a few options for their focal length with indoor and outdoor photography. With the touch of a button, the photographer can zoom in on a subject for a close-up picture and zoom out for a group shot, and the camera set on automatic exposure has sensors that will compensate for lack of light by adding a flash when necessary.

Tags: camera lens, your camera, lens camera, wide angle, automatic exposure, camera automatic, camera automatic exposure