HOW A DIGITAL CAMERA WORKS

Digital cameras store images on memory cards so pictures can be transferred easily to a computer.

 

A lens focuses the image on to a CCD unit or Charge-Coupled Device where the film would normally be.

 

So you can aim the camera accurately, there is an optical viewfinder.

 

So you can play back the images and decide which to keep and which to re-shoot, the image is passed to a small LCD screen on the back of the camera.

 

2. Listen to Part 1 of this discussion between A and B and complete this table of similarities and differences between conventional and digital cameras. Tick (v) or cross (x) the boxes.

 

Feature	Digital	Conventional
lens
viewfinder
requires chemical processing
film
transfer images directly to PC
can delete unsatisfactory images

 

3. Listen to Part 2 of the dialogue to list the disadvantages of digital cameras.

 

4. Now listen to both parts again to find the answers to these questions:

 

What does a CCD contain?

What is a pixel?

How can you view pictures before they are downloaded to a PC?

When you have downloaded the images, what can you do with them?

Is special software required?

Why is the resolution important?

What does the capacity of a digital camera depend on?

Why is it worth getting a rechargeable battery?

 

5. Compare digital and conventional cameras. Use the table from exercise 2.

 

6. Study this data about storage devices. Then complete the blanks in the following sentences comparing and contrasting the different types. Use the words: both, like, unlike, whereas, but, however.

 

Device	Read/Write	Speed	Media Capacity	Media Removable	Cost
Floppy disk	Read and write	Slow	Very low	Yes	Low
Fixed hard disk	Read and write	Fast	Very high	No	Medium
Removable hard disk	Read and write	Medium to fast	High	Yes	Medium
CD-ROM	Read only	Medium	High	Yes	Low
CD-R	Recordable	Slow	High	Yes	Medium
CD-MO	Read and write	Medium	High	Yes	High
DVD-ROM	Read only	Medium	High	Yes	Medium
DVD-RAM	Read and write	Medium	Very high	Yes	High
Magnetic Tape	Read and write	Very slow	High	Yes	Medium

 

You can write to hard disks …….. …….. optical disks.

Floppy disks have a ……… capacity ……… other devices.

CD-ROMs and floppy disks are ……… low priced.

DVD-RAM has a ……… capacity …….. other optical disks.

CD-ROMs cannot be re-recorded ……… some other optical disks can be.

……… hard disks, you can read from and write to CD-MO drives.

……… CD-ROMs, CD-Rs are recordable.

Magnetic tape is much ……… ……… other devices.

……… DVD-RAM and fixed hard disks have very high media capacity.

Floppy disks are cheap ……… DVD-RAM is expensive.

 

7. Write your own comparison of printer types.

 

Type	Speed	Text Quality	Graphics Capability	Color Quality	Cost
Dot-matrix	Slow to medium	Fair to good	Limited	Fair if you add a color option	Low
Ink-jet	Medium to fast	Good to excellent	Good to excellent	Good to Very Good	Low to high
Laser	Medium to very fast	Excellent	Good to excellent	Good in colour laser printers	Medium to high
Thermal Transfer	Medium to fast	Excellent	Good to excellent	Good to superior	Medium to high
Solid lnk	Medium to fast	Excellent	Good to excellent	Good	Medium to high
Electro-static	Slow to fast	Fair to good	Fair to good	Fair to good	Low to high

 

PROBLEM-SOLVING

8. Study this list of needs. Which type of peripheral would you advise in each case?

 

inputting printed graphics

building cars

controlling the screen cursor in a fast action game

making choices on a screen in a public information terminal

recording moving images

recording a book loan in a library

printing very high quality text and graphics

creating drawings

printing building plan drawings

recording sound

listening to music without disturbing others

storing programs and data

inputting a lot of text

backing up large quantities of data.