Digital Photography A tool for Graphic Design Graphic Design: Digital Photography

Digital PhotographyDigital Photography

A tool for Graphic Design

Graphic Design: Digital Photography

Digital CameraDigital Camera


A digital camera (or digicam)

is a camera that takes video or still

photographs, or both, digitally by

recording images via an electronic

image sensor.


The word digitaldigital comes from the same

source as the word digit and digitus

(the Latin word for finger), as fingers are

used for discrete counting. It is most

commonly used in computing and electronics,

especially where real-world information is

converted to binary numeric form as in ditigal

audio and digital photography.

PixelPixel


In digital imaging, a pixelpixel, the

smallest addressable screen element

in a display device; it is the smallest

unit of picture that can be

represented or controlled.

Image SensorImage Sensor


An image sensor is a device that

converts an optical image into an

electronic signal. It is used

mostly in digital cameras

and other imaging devices.


Today, the most currently used active

pixel sensors are digital:

charge-coupled device (CCD)

OR

complementary metal–oxide–

semiconductor (CMOS).

A CCD image sensorA CCD image sensor


A CCD image sensor is an analog device.

When light strikes the chip it is held as a

small electrical charge in each photo sensor.

The charges are converted to voltage one

pixel at a time as they are read from the

chip. Additional circuitry in the camera

converts the voltage into digital information.

A A CMOSCMOS imaging chip imaging chip


A CMOS imaging chip is a type of

active pixel sensor made using the

CMOS semiconductor process. Extra

circuitry next to each photo sensor

converts the light energy to a voltage.

Additional circuitry on the chip may be

included to convert the voltage to

digital data.

Focal LengthFocal Length


Cameras have lenses on them to focus

incoming light and direct it towards the

image sensor at the back of the camera.

Focal lengthFocal length in a camera can be best

described as the amount of information that

makes it to the sensor relative to the distance

the subject is away from the lens.

Light ExposureLight Exposure


In camera terminology, light is In camera terminology, light is

measured in what are called “stops.” measured in what are called “stops.”

One stopstop represents the increment between

one doubling and the next.

Exposure ControlsExposure Controls


Exposure is controlled by many different things.

Two of the most important ways to control the exposure are the aperture and shutter speed.

Exposure is the amount of light that makes it to the sensor at the back of the camera.

ApertureAperture


To control the amount of light that makes it to the sensor, a small opening is opened and closed on top of the iris called an aperture.

Cameras let light in through an iris.

Depth of FieldDepth of Field


The Aperture also controls Depth of Field. Depth of Field.


depth of field (DOF) is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image

Depth of FieldDepth of Field


Shallow Depth of FieldShallow Depth of Field


Large Large Depth of Depth of FieldField


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Shutter SpeedShutter Speed


The shutter on the front of the camera is a flap that opens and closes for small increments of time to allow light in.

Because there is limited space on the sensor for light to be absorbed, the shutter has to be very precise in how long it is open for.


By adjusting the shutter speed you can control the movement of your subject moving through your frame.

Shutter SpeedShutter Speed

A fast shutter speed will freeze the subject and a slow shutter speed will make it look blurred as the subject moves.


2000 1000 500 250 125 60 30 15 8 4 2 1 Bfast-------------------------------» slow ----------» shutter held open

These are the shutter speeds, expressed in fractions of seconds, that you will most commonly find on any semi automatic or manually operated camera.

Shutter SpeedsShutter Speeds


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Digital Photography A tool for Graphic Design Graphic Design: Digital Photography