Transcript Digital Cameras - Cape Fear Community College

Digital Cameras
A Computer with a Lens
Photographic
Goals:
Cost Comparisons
Advantages & Disadvantages
Instead of buying film:
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Take pictures.
Transfer to Computer.
Reuse same storage
device.
Immediate results.
Easy use of imageediting software.
Many options for
display and storage.
Initial investment.
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Time in learning how
to use equipment &
software.
Financial investment.
 The better the quality
desired the more
money required for
camera, printer, other
equipment.
Cameras: Traditional verse Digital
Commercial Processing Costs
24 exposure roll of color
film = $5.00
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Development & Printing
4”x6” Prints = $5.52 ($0.23 ea.)
Average price per print
including film, developing &
printing = $0.44 each.
Scanning Service
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Photo CD = $2.82
Digital Images presented on
Memory Device:
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4”x6” Prints = $0.22 each
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(50 or more = $0.19 each)
24 Prints = $5.28
Photo CD = $2.82
One Hour Processing Time:
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Traditional with Scanning.
Digital Images Printed.
Filmless Cameras:
Operate essentially in the
same way as conventional
cameras.
The lens contains a variableaperture diaphragm.
The camera has a shutter.
Many have an optical
viewfinder.
Some digital camera models
are built around existing
camera bodies and lens
systems.
The Core of a Digital Camera:
The Imaging Device: CCD (Charge-Coupled Device)
The sensor sits where the film
ordinarily would.
The sensor’s surface is
packed tight with
microscopic light-gathering
cells known as Pixels (picture
elements).
Similar to silver-halide
crystals in a film emulsionlarger pixels increase
camera’s speed-decrease
resolution.
In general, the more pixels a
digital camera has, the more
expensive it is.
The technical quality of a digital image is
determined by the number of pixels & the
amount of information each pixel holds.
The greater the number of
pixels: (pixels per inch or ppi)
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The greater the amount of detail
that is recorded.
The more information per pixel:
(bit depth or # of bits per pixel)
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The smoother the gradation from
one pixel to another.
Other factors also affect
quality:
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Enlargement
Quality of printer
(dots per inch or dpi)
Resolution and File Size:
Digital cameras are often described by their resolution.
(the number of pixels they can use for an image)
How resolution is calculated
Final
image size
Pixels
per inch
WAYS TO DESCRIBE CAMERA RESOLUTION
Pixels x Pixels
Millions of Pixels
Megapixels
Final file size
for color image
8 x 10 inches 200 ppi
1600 x 2000 pixels
3.2 million pixels
3.2 megapixels
9.6 megabytes
5 x 7 inches 200 ppi
1000 x 1400 pixels
1.4 million pixels
1.4 megapixels
4.2 megabytes
4 x 6 inches 200 ppi
800 x 1200 pixels
.96 million pixels
.96 megapixels
2.9 megabytes
The examples above use 200 ppi, which provides a large enough file for
adequate reproduction with most desktop inkjet printers. 300 ppi provides
even better quality.
In the first row, for example:
8” x 200ppi = 1600 pixels, 10” x 200ppi = 2000 pixels. Pixel by Pixel dimension = 1600 x 2000.
Now multiply 1600 times 2000. 3.2 million pixels is another way of describing resolution.
Each Pixel consists of 3 color values--red,green,blue—multiply the number of megapixels by 3.
A 3.2 megapixel camera will yield a file size of approx. 9.6 megabytes for a good quality 8”x10” image
Picture Storage: Most digital cameras store
their images on removable memory cards.
“Film” for a digital camera.
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Several competing types.
Different camera brands use
different types.
Capacities range from
128MB to 4GB.
Not all cameras have
removable cards.
When a card is filled, you
need to transfer its contents
to your computer
Choosing the quality you need:
Too much of a good thing!
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The bigger the file, the more space it occupies on the
memory card.
Tradeoffs-quality versus amount of memory.
Achieving smaller digital files.
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Use fewer pixels to take a picture.
Compress image files.
Combination of each.
Digital cameras let you choose.
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High Quality – uses the most pixels and/or compresses the
least.
How good is good enough?
Picture Format:Refers to a software scheme
that saves the information needed to create the
image.
How do you squeeze a large picture file into a
smaller space?
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Eliminate redundant information - Compression.
 “Lossless” – A TIFF format is an example.
 “Lossy” – A JPEG format is an example. (Saving an image repeatedly
in JPEG format will eventually degrade its quality).
You can downsize a high-quality file for the Web, but
you can’t make a large, beautiful print by expanding
a low-quality file.
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After transferring an image to the computer – always make
a copy and work with that. Thus, preserving the original at
its highest quality.
Original:
960 pixels x 1280 pixels @ 96 ppi = 3.52 M
10 inches x 13.3 inches
Original:
480 pixels x 640 pixels @ 72 ppi = 900 K
6.7 inches x 8.9 inches
The Lens:All photographic lenses do the
same basic job.
A CCD sensor is much
smaller than a frame of
35mm film.
The most important way
lenses differ is in their
focal length.
Focal length controls:
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Magnification
Angle of view
Depth of field
50mm lens on 35mm
film-based camera
50mm lens on equivalent-size
digital camera
Zoom Lenses:Combine a range of focal
lengths into one lens.
Optical Zoom: Magnifies the image by
the use of glass elements inside the lens.
Digital Zoom: Magnifies the image
through the use of electronics by enlarging
the pixels in the image.
As usual – Quality is the issue.
Kodak DC240 – Lens Specifications:
Optical quality glass
Maximum Aperture [wide:F/2.8, telephoto:F/4.5]
Zoom [6X:3X optical, 2X digital]
Focal Length [39 to 117mm (equivalent to 35mm camera), 6 to 18mm (actual)
Focus Distance [wide/telephoto: 1.6ft. to infinity, close-up:0.82ft. to 1.6ft.]
35mm Disposable Camera
With optical quality plastic lens
Approx. 35mm focal length.
6mm Focal Length
(39mm equivalent focal length on 35mm camera)
18mm Focal Length
(117mm equivalent focal length on 35mm camera)
Sony FD Mavica – Lens Specifications: 10X optical zoom lens
f = 6.0 – 60.0mm
F = 2.8
(39 – 390mm when converted into a 35mm still camera)
35mm Disposable Camera
With optical quality plastic lens
Approx. 35mm focal length.
6mm Focal Length
(39mm equivalent focal length on 35mm camera)
60mm Focal Length
(390mm equivalent focal length on 35mm camera)
Sony FD Mavica – Lens Specifications: 10X zoom lens
f = 60.0mm (39 – 390mm when converted into a 35mm still camera)
The maximum zoom magnification is 20X (2X digital zoom)
35mm Disposable Camera
With optical quality plastic lens
Approx. 35mm focal length.
60mm Focal Length
(390mm equivalent focal length on 35mm camera)
Digital Zoom
Macro Feature:
Lets you get an enlarged
image by focusing very close to a subject.
Often achieved
optically.
Best choice for
sharp close-ups.
Monitors & Viewfinders: Seeing
what you’ve got.
Optical viewfinders –
similar to conventional
cameras.
Liquid Crystal Display
(LCD) monitors.
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Optical
Viewfinder
LCD Monitor
Optical
Viewfinder
LCD Monitor
Great for close-ups.
Hard to see in bright light
or at certain angles.
Lets you see your
pictures almost as soon
as you take it.
TIP: An LCD monitor drains power, so use it when you need it, but your batteries
will last longer if you turn it off when you don’t need it.
White Balance:
Images are susceptible to
lighting conditions.
Normally, the camera will
adjust automatically.
If the image appears in
strange colors – change the
white balance mode.
Digital Imaging: An Overview
Choosing a Digital Camera:Many types
of digital cameras are available, from completely
automatic to full-function professional models.
Ideally-Look for a Camera with:
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LCD monitor plus an optical viewfinder.
A lens capable of optical zooming.
A flash that you can turn off.
Image Quality
Greater the resolution, the better the quality at a given
size and the more it costs.
Reaction Time
Length of delay between the time you press the shutter and
the moment the camera takes the picture, followed by the
delay while the image downloads.
Choosing a Digital Camera:Spend time
thinking about your needs before buying one.
Type of Memory
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Having a large amount of memory available means
more high-quality pictures before having to download.
USB and Firewire connections are desirable.
Batteries
Rechargeable nickel-metal hydride (NiMH) or lithium
batteries offer extra life and viewing time.
Creative Control
Consider the standard features you want on a traditional
camera – control over f-stops, shutter speeds, focus, etc.
Use a Digital Camera:
Get Started Today
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Every digital camera is different
 Read your manual carefully
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Make sure your camera has fresh batteries
Rechargeable batteries offer extra life
AC adapters useful indoors
 Have Fun!
Spend some quality time with your camera and
imaging editing software.
Manuals offer a variety of helpful
hints…
As well as specific Technical Data:
Many manufacturer’s post manuals online.
A printed copy of the
manual for the Nikon D50
Digital Camera is provided
each time the camera is
checked out.
Digital Cameras:
Your Path to Filmless
Photography
Unlimited Resources:
http://www.prenhall.com/london
http://www.kodak.com/eknec/PageQuerier.jhtml?pq-path=2/3/9/19&pqlocale=en_US
http://www.nikonusa.com/usa_home/home.jsp
http://www.nikonusa.com/template.php?cat=1&grp=2
http://support.nikontech.com/cgibin/nikonusa.cfg/php/enduser/std_adp.php?p_faqid=13644
http://www.fixya.com/ProductSearch.aspx?_s=Camera+Manual
http://www.powershot.com/powershot2/home.html
http://www.sonystyle.com/is-bin/INTERSHOP.enfinity/eCS/Store/en//USD/SY_BrowseCatalogImages and Excerpts were taken from the following texts for use in this
presentation:
Horenstein, Henry and Russell Hart, Photography. Upper Saddle River,
NJ: Prentice Hall, 2001
London, Barbara and J. Upton, K. Kobre & B. Brill, Photography. 7th ed.
Upper Saddle River, NJ: Prentice Hall, 2002
A Flash Can Be Useful:
No Fill Flash
Fill Flash Used