A good photographer
knows how to compose the subject for best light and
meaningfulness of portrait.
One of the most difficult tasks is to capture the moment.
c
lens
- regular lens
for everyday imaging
- macro lens for close up
- wide angle lens to capture more space
- telephoto lens for close-ups at a distance and to compose
portraits
d
shutter
- the shutter
controls the time light enters the camera for image recording.
- if the shutter is open a long time then the image sensor
will be flooded with light and the image will blur if it moves
while the shutter is open ( this is often desired) the image is
overexposed
- if a shutter is opened for a short time the subject will appear
to be frozen in time if it moves , the image sensor might be under
exposed
- digital shutter is electronic
but a digital sound may mimic the shutter sound of a film camera!
The same shutter speeds are used for digital and film for
historical reasons.
- film
cameras have a mechanical plate the opens and closes for fixed time
intervals usually measured in fractions of a sec. 1/8 1/32 etc.
e
aperture
- the aperture (iris) is like the iris
of your eye it can contract (close) or dilate (expand)
f
photo sensor
- an electronic photosensitive array called a
CCD is used
- the CCD has numerous
pixels that sense and save the light image as a set of voltage
readings that is interpreted by a microprocessor
- film made of emulsion that holds a light
sensitive silver based chemical
- this emulsion is called a negative (looks like an X RAY)
- the negative
g
processing
- the image is processed as a
digital signal and stored as a JPG/TIFF digital file on
a memory device
- negative is processed in a dark
room in an acid chemical bath and then allowed to dry
-
h
image
- printed out on printer
- viewed on a monitor
- posted on the Internet
- the negative is used to produce
a positive on another light sensitive film and then "fixed" so that
it can be handled and exposed to light for viewing
- a dark room is required
original image storage media
- flash card / memory stick/cd/floppy
etc.
-
- film negative
- negatives can be stored as very small physical elements
pixels that sense and save the light image as a set of voltage
readings that is interpreted by a microprocessor 