what is telephoto?

Question

it's use in Camera i don't know about this

Answer 1

Definition:

A telephoto lens is one which uses a diverging element or group of elements to make the light rays forming an image appear to have come from a lens further away. A simple 1000mm lens would have a distance of 1000mm between its centre and the film for taking distant objects; using a telephoto design this distance (and so the length of the lens) might be cut to perhaps half this.

Most long focal length lenses use a telephoto design, and the term is now commonly used for any lens with a focal length greater than that of a standard lens. These lenses have a narrower angle of view than the standard lens and magnify the subject more. As well as obvious uses in capturing wildlife and sporting events where close approach to the subject is not possible, these lenses also serve to isolate details of complex subjects - such as a face in a crowd.

Because of their greater magnification, fast shutter speeds are normally required, except for use with static subjects with the camera on a tripod. For handheld use a good rule is that the minimum safe speed is 1/focal length eg for a 500mm lens, 1/500 second. Fast film is normally required for most pictures with long telephotos.







In a 35mm system, a telephoto is any lens longer than 100 mm. Compared to a "normal" 50mm lens, a telephoto has a narrower angle of view. It thus gives apparent magnification to objects. It also seems to compress distant things, and there is less depth of field. A good telephoto lens is an essential part of any nature photographer's kit, and learning how to use one is an important skill. Because of their ability to magnify, these lenses are unforgiving of poor photographic habits.
The magnification given by a telephoto can easily be approximated. If a 50mm lens is considered "normal" because it approximates the angle of view of one eye (and the area we can see in good focus with both eyes), then a 100 mm lens will appear to double the size of an object; a 200 mm lens will increase the size by 4 times; a 300mm lens 6x, and a 400mm lens 8x. This last number is significant because it is also the magnification of most binoculars. Moving on, a 600mm lens magnifies 12x, 800mm 16x, and 1000mm 20x. The various camera manufacturers all build 600mm lenses; at least one builds a 1250 mm lens, and many make 1000mm "cat" or mirror lenses. Be aware that a good 400mm lens will cost over $1,000 and that the 600mm lenses cost around $10,000.


In biological imaging, telephoto lenses have several main purposes. The most obvious is to allow photographs of distant organisms to be made. Ideally, we would like to make all photographs with shorter lenses from close distances. Sometimes, however, the organism doesn't want you nearby, and will leave. Other times, you don't want to be too close to the organism! Telephotos have other uses, however. Equipped with extension tubes, they can also be used as long-distance macro lenses to photograph small but skittish organisms

Answer 2

The man has admited that he knows nothing about telephotos, so he asks what they are. Seems like if the man ask what time it was, everyone would be telling him how to build a watch.

A telephoto is a fixed length lens that makes the object you are photographing appear closer than it really is. It is not a zoom, which is a variable focus lens, it is what I call "straight glass" and has higher optical qualities than a zoom. Telephoto will be classified by a since focal lengh - 90mm, 105mm, 135mm, 150mm 200mm, etc, a zoom is classified such as this: 18-55mm, 28-150mm, 70 to 205mm. 80-300mm.

Zooms are convenience lenses, one lens about does it all, and we all use them from time to time. However, since there are moving elements in zooms, there is a tendency over time for them not to quite sit right, and thus you lose quality.

Answer 3

In photography and cinematography, a telephoto lens is a specific construction of a long focal length photographic lens that places its optical centre outside of its physical construction, such that the entire lens assembly is between the optical centre and the focal plane. A regular lens of a focal length that is longer than what is considered a normal lens is not necessarily a telephoto lens. A telephoto lens has to incorporate a special lens group known as a telephoto group (see below); nevertheless, non-telephoto lenses of long focal length are often informally referred to as telephoto lenses. The angle of view created by a telephoto lens is the same as that created by an ordinary lens of the same specified focal length.

Answer 4

Telephoto is a type of lens for an SLR (single lens reflex) camera that uses telescope like lenses to bring faraway images up close. Sometimes it's called a zoom lens.

Answer 5

A TELEPHOTO LENS BRING FARAWAY SUBJECTS CLOSER TO THE CAMERA. SAME AS WHEN YOU LOOK THROUGH A PAIR OF BINOCULARS.

Answer 6

It's a long zoom-in lens long enough for you to shoot a close up of soccer player during the soccer match.