Chapter 10

Digital

Imaging:

Capture

•Digital imaging – electronically producing,

viewing, or reproducing an image

•Pixel – a square with a uniform brightness and

color. Sometimes called a picture element.

• Resolution – number of pixels per unit of length

•Image size – physical size of a photo

• To understand digital imaging, compare it with conventional photography.

• First an image must be digitized.

• For computer use, this image is converted to digital form using CMOS or

CCDs (charge-coupled devices).

•Each position on the grid is recorded as a pixel.

• The amount of information in a digital image – and therefore

its technical quality- is determined by both the number of

pixels and the number of possible values each pixel can hold.

• The finer the resolution, the larger the number of pixels

needed.

• Without adding more pixels, increasing the image size,

decreases the resolution.

•Display allows you to see instant results of each shot

Advantages

•You get to select ISO rating for each shot

•Allows you to review your images before developing

Zoom Lenses

OPTICAL DIGITAL

•Magnifies the entire scene•Higher image quality

•Only enlarges pixels•Lower image quality

Using a Digital Camera

•Make sure you always have fresh batteries

•Never insert or remove your memory card while your camera is on!

•Select the file type - jpg

•There are many types of cameras so it’s important to find one that you

like, understand, and meets your needs

•Keep in mind the following factors when making your final decision

-Lens choice: some have interchangeable lenses others have fixed lenses.

-Image quality: the greater the resolution the better quality your image will

be. Test out cameras to make sure they meet your needs.

-Flash: built in flashes are useful but limited. Look into external flash units

to improve control and expand your options.

-Types of memory: Memory cards store images until you can transfer them

to a computer. The more memory you have, the more images you can

take and store at once. Storage space on memory cards varies greatly so

make sure you get one that will meet all you needs.

•Histograms show the brightness values of all the pixels in

an image

•On a digital camera you will find a histogram used as kind

of a digital light meter

•In scanning software and photo editing programs, the

histogram guides your lightness and contrast adjustment

tools

Normal High Low

•Gamut is the entire range of colors.

•The gamut of our eyes (all the colors we see) is much

greater than the gamut that can be printed.

•Digital imaging reproduces all the colors in the spectrum

by using the three primary colors: red, green, and blue.

•There are 256 color tones that can be used in printing.

•As soon as you create a digital image, you have to think about

storing it.

•Most digital cameras use removable memory cards for storage.

•Computers store images on their hard drives in binary form

using a combination of 1’s and 0’s.

•Adding additional external hard drives is a popular option for

storing large numbers of photo files.

•Most computers come with CD or CD/DVD recorders (or

burners) that allow you to store images on disks. These will

start to deteriorate in time.

PSD

TIFF RAW

JPEG

•Adobe’s proprietary format for saving Photoshop documents.

Images can be opened ONLY in Photoshop for editing.

•Compresses photos by discarding pixels determined to be

unnecessary. Repeated saving degrades the image.

•Most universal format for high quality photographs and can

be opened on any computer by nearly every program that works with photographs.

•Files are like exposed but undeveloped film. The files are

unprocessed and left just as the camera recorded them.

Quiz!

______________ is electronically

producing, viewing, or

reproducing an image.

1.

The finer the resolution, the _________ the number of pixels needed.

2.

_________ lowers image quality.3.

_________ show the brightness values of all the pixels in an image

4.

______ files are like exposed but undeveloped film. The files are unprocessed and left just as the camera recorded them.

5.