aperture-shutter-iso-digital jargon by huanghengdong

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									*Aperture
 *Shutter
  Speed
   *ISO
3 main controls on the camera adjust the amount
of light that reaches the film or sensor in the
camera.
               *Aperture
                *Shutter
                  *ISO



                                             2
    S
    H    S
    U    P
    T    E
    T    E
    E    D
    R
The shutter speed controls the length of time the
  shutter remains open. It can have a dramatic
        effect on how the picture looks.
                                                    3
Shutter speed range can be
expressed as:
1, ½ , ¼, 1/8, 1/15, 1/30, 1/60,
1/125, 1/250
with each one being a fraction of a
second.




    Faster shutter speed=less light=darker image




Slower shutter speed=more light=lighter image
*Slower shutter speed for slow or stationary objects

*Fast shutter speed for fast moving objects

Was this photo most likely taken with a shutter speed of
1/60 or 1/250?
                                                           5
Fast shutter speed is used for fast action
photography. The object in motion will be clear
and crisp.




                                                  6
  This is a photo showing blur motion. What
shutter speed was more likely used to take this
                     image?
                 1/25 or 1/250?




        BLUR MOTION=the appearance of motion.
     can be created when the shutter speed is slowed
 This is a photo showing stop motion.
  What shutter speed was most likely
        used to take this photo?
            1/60 or 1/1000?




STOP MOTION=stopping the action as if not moving.
  Can be created by using a faster shutter speed
*A Slow shutter speed is needed in low lighting
(shutter is open longer to let in more light)




                                        What was a more
                                      likely shutter speed
                                              used:

                                        1/30 or 1/500?




                                                         9
             Slow shutter speed and low lighting:
       Best if a tripod is used to avoid “camera shake”

CAMERA SHAKE: the movement of the camera during exposure 10
   TO AVOID “CAMERA SHAKE”:
  Minimum recommended
shutter speeds for hand held
        photography:
     24mm 1/30th
     28mm 1/30th
     50mm 1/60th
     70mm   1/60th
    90mm  1/125th
    135mm 1/125th
    200mm 1/250th
    300mm 1/250th
    500mm 1/500th

                        Fuji FinePix s1500 Lens: 33-396mm
    The Aperture:
The aperture (f/stop) adjustable
  small hole behind the lens.




                                   12
   The diameter of the aperture is controlled by f/stops

  Most camera’s have f/stops ranging in numbers from :
            f/2; f/2.8; f/4; f/5.6; f/ 11; f/16




 *Larger f/stop
number=smaller
aperture opening




                                                           13
   Think of the f/stop as being a fraction:
f/2 = ½, the diameter of the opening of the
                   aperture
                 f/16 = 1/16


                    *Smaller aperture=less light=darker image




                 *Larger aperture=more light=lighter image
                                                        14
The wider the aperture (small f/stop number), the better able
the camera would be to shoot in low lighting. The aperture
being larger, allowing more light in.




Would the f/stop most likely have been set at f/2 or f/16?
                                                                15
  When there is a lot of light present, a smaller aperture is
needed (large f/stop). A smaller aperture allows less lights in.
 Would the f/stop have more likely been set to f/22 or f/2.8?
  The aperture can also control the depth of
field. Depth of field is the area that is in focus from the
       foreground of the picture to the back ground.

            Zone of sharp focus=depth of field
Wide apertures, small f/stop #, produce a shallow
                depth of field




                  f/2.8 or f/22?                    18
             To achieve a shallow depth of field:
*ZOOM IN using the telephoto lens
*stand away from your subject-at least 6 feet (adjust your
distance if needed
*USE A WIDE APERTURE (SMALL f/STOP)
*Let your camera auto focus before you take the photo.




                                                         19
 Small apertures ensure everything from the
foreground to the background to be in focus:
            a large depth of field.
                f/2.3 or f/11?
         ISO (Film Speed)
*ISO: is the number indicating a digital camera
sensors sensitivity to light.




  *lower ISO number=requires more light.
  *Higher ISO number=requires less light.
Lower numbers result in images with the
least visible noise, which is desirable.

The higher the number, the more noise.
A Slower ISO produces a sharper images but requires
large amounts of light. A fast ISO can be used in low
light situations but will result in increased
noise/grain.
ISO 800   ISO 100
Noise in digital images
*Randomly-spaced speckles, known
as noise, can appear in digital images.
Noise is caused most often when
taking photos with a digital camera
using a high ISO number, usually over
ISO 100. When noise is present in a
photo, detail and clarity are reduced.
USING YOUR CAMERA’S LIGHT METER

*A light meter is an instrument inside your camera
that tells you if the amount of light reaching the
film will be enough or too much to properly expose
your image. The light meter takes into account your
shutter speed, film speed, and aperture settings
  A well-exposed image is only attainable if the
  amount of light that hits the film or CCD, is
  controlled correctly.

*To do this, the aperture,
shutter, and ISO need to
work as a system
         To experiment with how
 shutter/aperture/ISO work as a system,
have students now experiment with online
            camera simulators
       http://www.kamerasimulator.se/index_eng.php




          http://www.photonhead.com/simcam/
      NEXT:
  *Digital vs. Film
 *Types of cameras
        *Pixels
     *Resolution
*Digital Image Sensor
*Storing your images
      Advantages of Digital Camera
          over Film Cameras




SPEED: Images recorded by the camera can be transmitted directly
 into the computer without processing. CONSERVATION: Film and
                  chemicals are not expended.
       SAFETY: There is no exposure to processing chemicals.
Disadvantages of Digital Camera
      over Film Cameras




EXPENSE: These cameras cost must more than comparable traditional
cameras, and repair cost tend to be higher.
IMAGE QUALITY: Only
high-end digital cameras, with their superior resolution, can begin to
compare with the quality of film.
SHUTTER SPEED: Higher resolution
demands slower shutter speeds.
   Historical Perspective on Digital
               Imaging




    Let’s face it…digital photography has only been with us for
 about 10 years. It is still in its embryonic state. Digital technology
continues to evolve and become more technically sophisticated as
 quality keeps getting better and costs incrementally get less each
                 year for higher resolution cameras.
      TYPES OF DIGITAL CAMERA’S
         *SLR (Single Lens Reflex)
         -one single lens to both view a scene and
           capture an image.
         -the picture you take will be the same as the
           image you view through the lens
         -Interchangeable lenses
         -adjust settings manually

***Disadvantages: weight, size, cost,
          requires manual setting
    *Point-and-Shoots
*A Variety ofsizes and styles
*Most are capable of professional images
*uses one lens to view the scene, and a separate lens to
capture the desired image.
*requires very little manual adjustment
*lightweight
*moderate cost

*Disadvantages:
   -speed of use
   -focus is slower
   -quality of image may be less
   -limits artistic freedom
What is Digital Imaging?
   A digital or electronic, image is one that has been produced
   with a computer or camera. The machine (or digital
   camera) takes (captures) a visual image and translates it
   into a series of mathematical values ones and zero's, or bits
   of information.

                   Digital Photography- you
                      are digitalizing the
                             image
An image from your camera is composed of tiny
       squares call pixels.
Pixel—(Picture Element)
The smallest element of a digitized image.
One small dot of light.


Pixels form an image like
pieces of a mosaic. A
digital image is a grid of
pixels.
   -each one is exactly
one color/value/shade
   -each pixel is
independent
   -each pixel is a square
   -smaller is better-the
smaller the pixel is, the
more pixels in an
image=greater clarity
Resolution: is used to refer to the total
number of pixels in a digital image
 Resolution is measured in ppi=“pixels per inch”
 The higher the resolution, the more pixels in an
image and therefore the greater the image quality.
Camera resolution: the number of pixels your
camera is capturing an image at.
MEGAPIXEL—A unit equal to one million
pixels
-small snap shot size print/graphic (4”x6” or 5”x7”):1-3 mega pixels
-larger photos (8”x10” or 11”x14”): at least a 6 mega pixel
640 x 480   1024 x 768 2272 x 1704
Image resolution: size of your images
individual resolution when you print




            dpi=dots per inch
        Digital Imaging sensor
           (the camera’s “film”)
*CCD (charge-coupled device). It’s job is
to turn photons (light) into electrons.

*The vast majority are silicon based
which is light sensitive.

*also used in scanners and copiers
       Storage of your images
 Storage
    Internal
    Removable
        Compact Flash
        Memory Stick

        Smart Media
         (memory card)
Their storage capability is measured in
MB’s=MEGA BYTES.
Computer memory is stored in “bytes.” A
megabyte is 1,000,000 bytes

								
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