Telephoto lens
A
telephoto lens is a type of camera lens designed for taking photographs of
objects at moderate to far differences. Also known as a ‘tele lens’, they are a
type of long – focus lens which use a specific internal construction to give
them a focal length much longer than the length of the length itself. This
makes them smaller, lighter and easier to handle, while still giving excellent long
range capabilities.
They are commonly used while photographing
sports events, wildlife and in any other circumstances where the photographer
can’t get close to the object. They are also popular in portrait and macro
photography as they produce a pleasing natural perspective, free from the
distortion caused by using a wide angle lens.
They come in both ‘prime ‘(fixed focal
length) and zoom varieties. Those with fixed focal length tend to be of higher quality,
although the zoom lenses offer the obvious advantage of greater flexibility.
Focal length typically starts at around
85mm and extend up to 800mm and beyond. Longer focal length is able to capture
more distant details, but is also more expensive, bigger and heavier.
Because of the variation in focal length,
they can be classified into three types;
i.
Short telephoto lenses
These are ideal for
shooting portrait and candid shots i.e. (weddings) where you are quite close to
the object but don’t want to intrude too much.
They are compact and light
weight, and can be hand held for fast shooting.
ii.
Medium telephoto lenses
These are popular with
sports and action photographers who can get quite close to the action. For this
type, aperture is critical in minimizing blur, particularly when photographing
fast moving objects.
iii.
Super telephoto lenses
These are a popular choice
for professional wildlife and nature photographers, as well as sports
photographers who can’t get close to the action.
The longest lenses have
telescope – like magnification making them great for astrophotography.
They are extremely
expensive.
Zoom lens
This
is a mechanical assembly of lens elements for which the focal length can be
varied, as opposed to a fixed focal length lens.
The lens has a variety of focal lenses.
A zoom lens maintains
focus when its focal length changes.
Zoom lenses are often
described by the ratio of their longest to shortest focal lengths i.e. a zoom
lens with focal lengths ranging from 100mm to 400mm may be described as a 4:1
or “4x” zoom
Super zoom is used to
describe photographic zoom lenses with very large focal lengths factors, typically
more than 5x and ranging up to 18x in SLR and 50x in amateur digital cameras.
This ratio can be as high as 300 times in professional television cameras.
Standard
lenses
This is also known as
normal lens.
A standard lens is one
which produces an image which roughly matches what the human eye sees, and
which looks natural to the viewer. It sits between the telephoto lens and the
wide angle lens, which produce unnaturally zoomed - in and zoomed - out images
respectively. They have an angle of view of about 50 – 55 degrees diagonally.
This is roughly the same as the angle that the human eye can comfortably view.
They make great general
purpose lenses and can be used to photograph everything from close up portraits
to landscapes. They have wide aperture making them great for indoor and low
light photography. They usually have a focal length of 50mm.
Wide angle lens.
Referrers to a lens whose
focal length is substantially smaller than the focal length of a normal lens
for a given film plane. This type of lens allows more of the scene to be
included in the photograph which is useful in architectural, interior and
landscape photography where the photographer may not be able to move further
from the scene to photograph it.
It can also be used where
a photographer wishes to emphasize the difference in size or distance between
objects in the foreground and background; nearby objects appear very large and
objects at a moderate distance appear small and far away.
Wide angle lens also
projects a substantially larger image circle than would be typical for a
standard design lens of the same focal length. This large image circle enables either
large tilt or shift movements with the view camera, of with field of view.
Have a focal length of
35mm and below.
Examples,
i.
Fisheye lenses
These are ultra wide angle
lenses that do not produce a rectilinear image.
Have a focal length of 6 –
8 mm
ii.
Ultra
wide angle lenses
Have focal lengths of less
than 24mm
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