The Camera System - PowerPoint Presentation

Slide1

The Camera System

A Quick Overview throughout HistorySlide2

In its simplest form a camera as a device has three interacting systems

A viewing/Focusing system

A light control systemImage Reciever SystemSlide3

A simplistic pinhole camera has no viewing or focusing system while more complex camera systems allow for adjustment of focus and viewing of the frame.

Viewing and Focusing SystemSlide4

The most Simplest form of Separate Viewfinder was the plain wire frame called the “Sports Finder”

This would allow a photog. To quickly frame an action shot using a large cumbersome press cameras of the past

Viewing MethodsSlide5

Much more common is the separate viewing window used in cameras from disposables to classic and modern “Range Finder” models

Another form of separate view finder is the TLR ( Twin Lens Reflex)

TLR’s have one lens for viewing and focusing the shot and another for taking the photoSlide6

Separate View finders can be effective for most shots but can cause problems for close up shots.

The most common problem is known as

Parallax Error which is a mis-match of what the photographer sees and what the camera actually photographs resulting in part of the image being cut offSlide7

On cameras that have the ability for interchangeable lenses and a separate view finder the problem of the field of view to the format of the lens occursSlide8

Is as close as you can get to what you see is what will be captured on the Image.

Single Lens Reflex shows most of what the lens is capturing through a unique use of mirrors and lenses

Most SLRs have 92-95% of the image featured in the view finder. The more professional the camera this number can go up to 100%

Through- the lens Viewing SystemsSlide9

Much like the through the lens viewing system the electronic view finder will take what the lens is projecting onto the sensor and feature it on an LCD screen

Although it is accurate many of the finer details in an image can be lost because of the LCD screen

The LCD can also become washed out in sunlight and may not be an effective viewfinderMany camera companies now offer “Hoods” to allow the

photog

to see the image in sunlight

Electronic View FindersSlide10

With a through lens camera focusing is also “what you see is what you get.”

The photographer will turn the lens barrel and the image in the view finder will become sharper or more diffused

When it is at it’s sharpest we say that the image is “in focus”

Focusing MethodsSlide11

Some Cameras use aids to help the photographer get the camera into focus.

A split- prism is a focusing aid that usually has a horizontal line

When an image is out of focus the image will be mis-aligned on either side of the split prism line

Manual Focusing AidsSlide12

Microprism is another form of focusing where the image will be broken up by multiple diamond shapes if not in focus

Some cameras

have the view finder covered in the microprism diamonds while others will just use a ring of micro prism around a split prism.

Manual Focusing AidsSlide13

Range finders were a style of camera that had a separate view finder.

They would be focused by finding out the distance of the subject to the camera

Focusing these cameras tended to take two overlapping images or a split image and moving them into alignment

Range Finder FocusingSlide14

Modern day cameras now all have the capability of Auto-focus that will easily focus the image

These Auto-focus systems are broken down into Active and Passive auto- focus

Auto- FocusSlide15

Is the system most predominant in point-and-shoot cameras that are being used predominantly for snap shots

It sends out an infrared beam that bounces of the subject and then back to the camera

The delay of return will allow the camera to calculate the distance and focus the camera for that distance

Active Auto FocusSlide16

Problems arise when the infrared beam is not focusing on the subject

Many of the beams go to the center of the image, if the

subect is off to the side in a rule of thirds composition, the subject will not be in focusSome cameras will allow you to focus on the subject in center then will “lock in” the focus so you can set up the composition again

Another problem arises in taking action photos of a subject that is changing range distances rapidly

It takes a few seconds to go through the auto focusing process

Problems with Active Auto-FocusSlide17

PAF systems are used in very high end professional grade cameras

The PAF systems used in today’s digital and film SLRs make use of multiple sensors and computer circuitry to quickly and

precisly achieve focus under almost any conditionThe user can also select what sensors or combination of sensors are active

Passive Auto- FocusSlide18

The amount of light that accesses the digital sensor or film is

controled

by the camera’s light control systemThis system is made up of the len’s Aperture

and the

Shutter

These two components can work together or independently to regulate how much light comes in to contact with the light sensitive material

Light Control SystemSlide19

The word aperture means opening

It is a hole that can fixed or variable size depending on the age of the camera

Classic pin hole cameras would have fixed aperturesIt can be located in the camera body or the lens assembly

ApertureSlide20

Two types of varying the aperture size

The first is a series of different sized fixed openings

Early boxed cameras and even some first generation snap shot cameras were equiped with a rotating plate with two or more opening sizes

The

photog

could rotate the plate to desired size

Methods of Varying ApertureSlide21

Large “view cameras” of the 19

th

century had individual plates with precisley different sized holes cut into the plateThe plate would be slid into the camera behind the lens

Later a larger single plate with multiple sized holes was used

These plates were known as

WATERHOUSE STOPSSlide22

The

Diaphram

or Iris is a variable aperture device that consists of thin overlapping bladesOn modern SLRs the iris is mounted in the

interchangable

lenses and the size is adjusted by rotating a ring on the lens barrels

This gives you an infinite amount of different sizes of

aperature

The second form of varying ApertureSlide23

On the ring that controls the iris are a series of specific size openings.

These are standard sized apertures and are known as

F-StopsThese f-stops have a constant relationship of doubling in sizeAs the f# gets larger the aperture gets smaller

F- StopsSlide24
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The size of the opening has a direct relationship to how much of the picture will be in sharp focus

The zone of sharp focus is known as

the depth of fieldThe larger the aperture opening the smaller the depth of field will be

Aperture and Depth of FieldSlide26

The role of the shutter in the camera is to operate like a valve or

faucuet

and control the amount of light that contacts the image recieverMost shutters are mechanical and physically open and close

They are broken down into two types

The Shutter SystemSlide27

Located in the lens assembly

Usually used in simple, inexpensive small cameras, some medium format cameras, and all large format/ studio cameras

The oldest and most simple shutter is a spring loaded disk that would have a hole in itPressing and releasing the shutter button would create and release tension on the spring which would bring the disk’s hole into alignment with the

aperature

Between the Lens ShuttersSlide28

A more complex mechanism that makes it possible to adjust shutter speeds is the leaf shutter

It allows the

photgrapher to create more or less tension on the springs which adjust the time frame the shutter stays open

The leaf shutterSlide29

These shutters are located in the camera body just

infront

of the image recieverThese are almost universally used in SLR digital and film camerasConsists of two flexible pieces of metal or sturdy cloth known as curtains that slide over the image receiver in sequence. The lag time between the two curtains can be controlled

Focal Plane ShuttersSlide30

Shutter speeds, like f-stops have a constant relationship

The length of time the shutter is opened doubles as it increases

Shutter speedsSlide31

Shutter speed plays a key role in achieving proper exposure along with the aperture

It is also the primary means of controlling camera and subject motion

Blurring of a photo due to camera movement is usually always undesirableBlurring due to subject movement has positive and negative aspects

Shutter Speed and Motion ControlSlide32

Is the invouluntary

movement of the camera during exposure

Typically occurs when hand holding a camera at slower shutter speeds

Camera ShakeSlide33
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