Basic Photography Course

Tungsten-Halogen Lamps

Tungsten-halogen lamps have a tungsten filament

inside a quartz envelope. This type of lamp does not
blacken the inside of the envelope and operates at an
almost constant brightness and color temperature
throughout its life. Tungsten-halogen lamps for
photography operate at color temperatures of 3200 K

and 3400 K. Filters can be used to convert them to
daylight. For its size, a tungsten-halogen lamp generally
delivers more light than a conventional 3200 K lamp.
Tungsten-halogen lights are becoming more popular
and are rapidly replacing regular tungsten lights for
general photographic use.

Fluorescent Lamps

Pictures made on daylight type of color films under

fluorescent lights without a filter may be acceptable;
however, they usually have a greenish cast. When a
tungsten type of color film is used with a fluorescent
lamp without a filter, the pictures usually are too blue.

Fluorescent light is not generated by heat, as are

other types of light. It has special characteristics
different from either daylight or tungsten light.
Fluorescent lights have no true color temperature, but a
value of approximate color temperature has been
worked out.

Daylight fluorescent lamps: 6500 K

Cool, white fluorescent lamps: 4500 K

Warm, white fluorescent lamps: 3500 K

Electronic Flash Lamps

Electronic flash is an excellent light source for both

outdoor and indoor photography, especially when the
predominant lights are fluorescent. Electronic flash uses

a discharge tube filled with xenon gas and is supplied
with a powerful charge of electricity from a capacitor.

The flash is triggered by means of an electrical current
that ionizes the gas. The output, or intensity of the flash,
is usually given in effective candlepower-seconds and
depends on the voltage and size of the capacitor. The
design of the reflector on an electronic flash has a direct
relationship on the efficiency of the unit.

Electronic flash resembles daylight in color quality

and is excellent for exposing daylight type of color
films. The duration of the flash is short, usually 1/500
second or less. With a computerized (automatic) unit
used close to the subject, the flash duration can be as

Figure 1-13.耍 lamp reflector can increase the intensity of light

reaching the subject.

short as 1/50,000 second. Computerized electronic flash
units have a sensor that switches off the flash when the
subject (depending on its distance and tone) has received
enough light for proper exposure.

Reflectors

Two types of reflectors are of importance in

photography. They are the lamp reflector and the plane

reflector. The first type, the lamp reflector, is used with
artificial light sources-tungsten, tungsten-halogen,
fluorescent, and electronic flash lamps to direct the light.
The second type, the plane reflector, is used to redirect
light from any kind of light source into shaded areas to
soften or lighten shadows. (While it is true that mirrors
are also reflectors, reflector is used in photography as a
more general term. Mirrors always reflect specular light;
and reflectors reflect either specular or diffused light.)

LAMP REFLECTORS.

胎ight emitted by the

filament of a lamp is dispersed in all directions. This is

useful when the lamp is for general illumination, such

as one suspended from the ceiling to light a room. As a

photographer, however, you are usually interested in
illuminating only a given area, and it is, therefore, to

your advantage to concentrate the light emitted by a

lamp onto the area of interest. You can do this by

mounting the lamp in a concave reflector that reflects
almost all the light onto the area to be photographed
(fig. 1-13). Lamp reflectors generally have a satin or
matte finish to diffuse the reflected light to prevent hot
spots that could result if the reflector surface were highly
polished.

Reflectors of electronic flash units vary con-

siderably in their efficiency and covering power at

1-9

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Basic Photography Course

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DOFMaster for Windows On-line Depth of Field Calculator DOFMaster for Mobile Devices On-line Depth of Field Table Hyperfocal Distance Chart Articles FAQ Recommended Books Support Contact Links Home As an Amazon Associate I earn from qualifying purchases.	contents <- previous page next page -> Tungsten-Halogen Lamps Tungsten-halogen lamps have a tungsten filament inside a quartz envelope. This type of lamp does not blacken the inside of the envelope and operates at an almost constant brightness and color temperature throughout its life. Tungsten-halogen lamps for photography operate at color temperatures of 3200 K and 3400 K. Filters can be used to convert them to daylight. For its size, a tungsten-halogen lamp generally delivers more light than a conventional 3200 K lamp. Tungsten-halogen lights are becoming more popular and are rapidly replacing regular tungsten lights for general photographic use. Fluorescent Lamps Pictures made on daylight type of color films under fluorescent lights without a filter may be acceptable; however, they usually have a greenish cast. When a tungsten type of color film is used with a fluorescent lamp without a filter, the pictures usually are too blue. Fluorescent light is not generated by heat, as are other types of light. It has special characteristics different from either daylight or tungsten light. Fluorescent lights have no true color temperature, but a value of approximate color temperature has been worked out. Daylight fluorescent lamps: 6500 K Cool, white fluorescent lamps: 4500 K Warm, white fluorescent lamps: 3500 K Electronic Flash Lamps Electronic flash is an excellent light source for both outdoor and indoor photography, especially when the predominant lights are fluorescent. Electronic flash uses a discharge tube filled with xenon gas and is supplied with a powerful charge of electricity from a capacitor. The flash is triggered by means of an electrical current that ionizes the gas. The output, or intensity of the flash, is usually given in effective candlepower-seconds and depends on the voltage and size of the capacitor. The design of the reflector on an electronic flash has a direct relationship on the efficiency of the unit. Electronic flash resembles daylight in color quality and is excellent for exposing daylight type of color films. The duration of the flash is short, usually 1/500 second or less. With a computerized (automatic) unit used close to the subject, the flash duration can be as Figure 1-13.耍 lamp reflector can increase the intensity of light reaching the subject. short as 1/50,000 second. Computerized electronic flash units have a sensor that switches off the flash when the subject (depending on its distance and tone) has received enough light for proper exposure. Reflectors Two types of reflectors are of importance in photography. They are the lamp reflector and the plane reflector. The first type, the lamp reflector, is used with artificial light sources-tungsten, tungsten-halogen, fluorescent, and electronic flash lamps to direct the light. The second type, the plane reflector, is used to redirect light from any kind of light source into shaded areas to soften or lighten shadows. (While it is true that mirrors are also reflectors, reflector is used in photography as a more general term. Mirrors always reflect specular light; and reflectors reflect either specular or diffused light.) LAMP REFLECTORS. 胎ight emitted by the filament of a lamp is dispersed in all directions. This is useful when the lamp is for general illumination, such as one suspended from the ceiling to light a room. As a photographer, however, you are usually interested in illuminating only a given area, and it is, therefore, to your advantage to concentrate the light emitted by a lamp onto the area of interest. You can do this by mounting the lamp in a concave reflector that reflects almost all the light onto the area to be photographed (fig. 1-13). Lamp reflectors generally have a satin or matte finish to diffuse the reflected light to prevent hot spots that could result if the reflector surface were highly polished. Reflectors of electronic flash units vary con- siderably in their efficiency and covering power at 1-9 contents Basic Photography Course <- previous page next page ->	As an Amazon Associate I earn from qualifying purchases.
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