Lenses for cameras

The different lenses and options for cameras

Long lenses

W

ide and long lenses make a stronger statement about the decisions a photographer must make

such as with perspective and depth of field.

L

ong lenses are best for close ups and photographing animals that are far away.

L

ong lenses produce better pictures.

L

ong lenses are bulkier, heavier, and more expensive.

L

ong lenses have less depth( objects in the background can be photographed out so the subject is

seen clearly).

L

ong lenses produce better portraits.• When you take a picture of a person close to the lens the features closest to the camera appear to large

and give the head an unusual dimension.

Wide Angle lens

Wide angle lenses have a considerable amount of depth of field.• Photographers who work in fast moving situations usually use a

moderately wide lens (such as 35mm) as their normal lens.• They don’t have to pause to focus after each shot so the scene stays

sharp and doesn’t display too much distortion.

A

wide angle lens an also show an apparent distortion of perspective.• Caused by the position of the photographer not the lens.• Objects closer to the lens appear larger than an object of the same size

that is farther away.

Zone focusing

Z

one focusing lets you set depth of field in advance of shooting.

I

t is good for rapid shooting.

T

o zone focus lens’s depth of field scale to find the frame stop setting that will give

you depth of field.

Z

one focus works best with short focal length lenses.

F

or depth of field in a scene that extends to a afar distance, don’t focus on infinity.

Zoom lenses

Z

oom lenses are popular because they combine a range of focal lengths

into one lens.

A

zoom lens is useful for getting the image right the first time.• Cropping a photograph after the exposure and then enlarging it lowers

the quality of the image.

T

he lens elements inside a zoom can be moved in relation to one another.• This changes the focal length which changes the size of the image.

Zoom lens

A

zoom has some disadvantages• Zoom lenses are more expensive, bulkier, and heavier.• One zoom lens can replace two or more fixed-focal-length lens.• The greater the range, the more evident the disadvantages become.

S

ome zoom lenses are best used where light is ample because they have a

relatively small maximum aperture.• Zooms that keep the same maximum aperture at all focal lengths reduce

the size of the maximum aperture as their focal lengths increase. • With zoom, be careful to make sure the shutter speed of the camera is

fast enough to avoid blur caused by camera movement. • Most zoom lenses work best outdoors.

lenses

M

acro is useful for extremely close shots

T

he lens let you focus at a very close range and is corrected for aberrations that occur at

close focusing distance.

S

ome zoom lenses have a macro feature that focus closer that a non-macro zoom but not

as close as the a fixed focal length macro lens.

A

berrations are deliberately introduced in soft-focus lens, also called a portrait lens.

T

he goal is to produce an image that will defuse and soften details like wrinkles.

lenses

F

or the widest of wide angle views consider the fisheye lens

A

fish eye has a very wide angle of view (some more than 180º) that exaggerates

to an extreme degree difference in size between objects that are near to the

camera and objects that are farther away.

I

n it’s design is barrel distortion which is an optical aberration that bends

straight lines to make curves along the edge of the image.

F

isheye lens produce great depth of field ,

lenses

A

perspective-control lens brings some view camera adjustment to other types of

cameras.

T

he lens shift in different directions to prevent parallel lines from tilting towards

each other, such as on a building.

A

catadioptric, or mirror lens, is similar in design to a reflecting telescope.

I

t has curved mirrors as well as galss elements within the lens.• Results in a long focal length but a modest size.• It has a fixed aperture which is usually rather small.

Focus

I

mage stabilization can be built in to a lens.

M

icrometers adjust to the position of special floating lens elements.

A

utomatic focus does the focusing for you.

I

n simple designs, you can press the shutter release button and the

lens will bring the image into focus.• Works well when the main subject stays in the middle of the picture.

Focus

I

f your subject is not in the center you can use auto focus lock to make it sharp.

1.F

rame the subject within the focusing brackets or point the camera straight at it.

2.T

emporarily lock the focus by pressing halfway down on the shutter release button.

3.K

eep it pressed and then reframe the scene.

4.P

ress it all the way down to take a picture.

Focus

W

ide-area focus systems provide more options.

S

ome viewfinders have more than one focusing bracket.

Y

ou can rotate the dial on he camera back to select the bracket that

covers the area you want to be sharp.

W

hen you press the shutter, the camera will focus on the area and will

allow you to shoot fast moving objects.

FocusO

nce you lock onto a subject, some cameras predict where the subject is likely to be next while

keeping the subject in focus.

T

he tracking system can lock onto the subject, adjusting the subject as the subjects move closer or

farther from the camera.

W

orks well if the subject is moving at a constant speed.

Y

ou camera may let you select among its several focus modes.

M

anual focus has two other options.• Single shot autofocus (focus priority)• Continuous focus

focusS

ome cameras have autofocus systems.

R

ead your camera’s instructions.• You can understand how the autofocus mechanism operates and when you would be better

off focusing manually.

A

ctive autofocus sends out a beam of infrared waves that bounces back to measure the distance to

the subject.

P

assive autofocus looks at the image inside of the camera.

C

ameras that empty both systems are most likely to find maximum sharpness under most

conditions.

Focus

A

n autofocus system can be fooled.

T

his camera doesn’t what you are trying to photograph,

so unwanted subjects can cause the lens to focus

incorrectly.• if you are focusing on a goalie, and the referee moves

in front of the camera it may focus on the referee.

SharpnessWhat exactly is sharpness and how can it be

controlled?

A lens can only focus on a flat plane at one

single distance at a time and objects in other

distances will be less sharp.

Objects will become more and more out of

focus the farther they are from the focus

distance.

DEPTH OF FIELD

D

epth of field is the part of the scene that appears acceptably sharp in

the photograph.

D

epth of field can be shallow or deep; no definite endings to it.

T

o an extent, you can control how much of it will be sharp.

O

bjects gradually change from sharp to soft the farther they are from the

focused distance.

perspective

T

he camera image can seem surprisingly different from reality.

P

erspective is the way the brain judges depth in two dimensional

representation.

D

epth is perceived mostly b7 comparing the sizes of objects.

L

ooks like it increases if foreground objects appear larger than the

background ones.

Perspective

P

erspective is affected by the lens-to-subject-distance, not by lens focal

length.

M

oving your camera closer to the subject will make objects in the

foreground larger relative to those in the background.

T

he shortest lens provides the widest view

T

he longest lens gives the narrowest view

PerspectiveI

n only one sense does the focal length of a lens affect the perspective.

A

short lens can focus closer to an object than a long lens.• It doesn’t eliminate most of the scene from view when you move in close.• Can produce wide angle distortion because it is easy to use up close

A

long lens can produce a telephoto effect because you are more likely to

shoot from far away.• The lens isn’t creating the effect, the distance from the subject is.