Chapter Seven
Focus
The adjustment to place the
sharpest focus where it is desired on the subject .
Aperture
Adjustment of the lens opening,
measured as f-number, which controls the amount of light passing through the lens.
Aperture also has an effect on depth of field and diffraction the higher the f-number, the smaller the
opening, the less light, the greater the depth of field, and the more the
diffraction blur. The focal length divided by the f-number gives the effective
aperture diameter.
Shutter Speed
Adjustment of the speed (often
expressed either as fractions of seconds or as an angle, with mechanical
shutter) of the shutter to control the amount of time during which the imaging
medium is exposed to light for each exposure. Shutter speed may be used to
control the amount of light striking the image plane; “faster” shutter speed
(that is, those shorter duration) decrease both the amount of light and amount
of image from motion of the subject and/ or camera
White Balance
On digital cameras, electronic compensation for the color temperature
associated with given set of lighting conditions, ensuring that white light is
registered as such on the imaging chip and therefore that the colors in the
frame will appear natural. On mechanical, (ISO)film-based cameras , this function is served by the
operator’s choice of the film stock or with color correction filters. In
addition to using white balance to register natural coloration of the image,
photographers may employ white balance to aesthetic end, for example white
balancing to a blue object in order to obtain a warm color temperature.
Metering
Measurement of exposure so that
highlight and shadows are exposed according to the photographer’s wishes. Many
modern cameras meter and set exposure automatically. Before, automatic
exposure, correct exposure was accomplished with the use of a separate light
metering device or by the photographer’s
knowledge and experience of gauging correct settings. To translate the amount
of light into a usable aperture and shutter speed , the meter needs to adjust
for the sensitivity of the film or sensor to light. This is done by settings
the “film speed” or ISO sensitivity into the meter.
Artificial Light
Light from a man made source , such
as flash unit, household bulb and fluorescent tube light.
Charge Coupled Device (CCD)
A microchip made up of light
sensitive cells and used in digital cameras for recording images
Depth of Field
The zone of acceptable sharpness, in front and behind of the subject,
on which the lens is focused . Depth of filed is dependent on the aperture set
the focal length of the lens and focusing distance. The smaller the aperture
the shorter the lens and the farther the focusing distance the greater the
depth of field
Exposure
The quantity of light allowed to
act on a photographic material.
Film Speed
The sensitivity of a given film to
light, measure in ISO.
Flash
A form of artificial light
generated by the full or partial
discharge of a capacitor.
Flash Synchronization
The synchronization of flash
duration and shutter speed
Focal Length
The distance between the film and
the optical center of the lens when the lens is focused on infinity measured in
millimeters.
Focus
Adjustment of the distance setting
on a lens to define the subject sharply, generally the act of adjusting a lens
to produce a sharp image
Grain
Minute Metallic Silver deposit
forming in quantity the photographic image on film
Guide Number
A figure that denotes the maximum
power of a flash unit at a
distance. It is normally given in meters
or feet when used ISO-100 film.
Shutter Speed
The length of time the shutter is
open, measured in seconds or fraction of a second
No comments:
Post a Comment