Chapter Thirteen
Correct (exposure) depends on three things i.e.
*Aperture, Shutter speed and ISO*
(Film speed). In photography, exposure is the total amount of light allowed to
fall on the photographic medium (Photographic film or image sensor) during the
process of taking a photograph. Exposure is measured in lux seconds, and can be
computed from exposure value* (EV)*
and scene luminance over a specified area.
In photographic terminology,
an exposure generally refers to a single* (shutter
cycle)*. For example: a long exposure refers to a single , protracted
shutter cycle to capture enough
*low-intensity*
light, whereas a multiple exposure involves a series of relatively
brief shutter cycles; effectively layering a series of photographs in one
image. For the same film speed, the accumulated photometric exposure *(H)* should in both cases.
“Correct” exposure may be defined as an exposure that
achieves the effect the photographer intended. The purpose of exposure
adjustment (in combination with lighting adjustment) is to control the amount
of light from the subject that is allowed to fall on the film, so that it falls
into an appropriate region of the film’s characteristic curve and yields a “correct” or acceptable exposure.
Overexposure
and Underexposure
A photograph may be
described as overexposed when is has a loss of highlight detail, that is, when
the bright part of an image are effectively all white, known as “blown out
highlights” (or ”clipped whites”). A photograph may be described as
underexposure when it has a loss of shadow detail, that is , the dark areas
indistinguishable from black, known as “blocked up shadows” (or sometimes “crushed
shadows”, “crushed blacks”, or “clipped blacks,” especially in video). As the
image to the right shows, these terms are technical ones rather than artistic judgments;
an overexposed or underexposed images may be “correct”, in that it provides the
effect that the photographer intended.
Types
of Exposure
There are three types of
exposing, Bird Eye View, Human Eye View, Worm Eye View.
Bird Eye View
A Bird’s eye view is an
oblique view of an object from above, with a perspective as though the observer
were a bird, often used in the making of blueprints, floor plans and maps.
Human Eye View
A Human
Eye View is a view of an object from equal
level or eye-to-eye level.
Worm Eye View
A worm’s-eye-view is a view
of an object from below, as though the observer were a worm; the opposite of a
bird’s-eye-view. A worm’s eye view is used commonly for third perspective when
you put one vanishing point on top one on the left and one on the right.
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