loops 

Electrical light sources and lighting fixtures. The History of Lighting - From Ancient Fire to Modern LED Lights can distribute light in different ways, so they are categorized according to the nature of the light they create. The lighting created

The main purpose of lighting fittings is the redistribution of lamp light in space. In addition, light fittings are able to transform the properties of lamp light (polarize it or change the spectral composition). No less important are such functions of light fittings as mounting the lamp and supplying power to it from an energy source, protecting the lamp from mechanical damage and from environmental influences.

The main classification of lighting devices

As mentioned, lighting devices are divided according to their purpose into lighting and light signaling. At the same time, their designs and optical systems do not have fundamental differences.

If lighting devices are considered from the point of view of the redistribution of light, then they can be divided into three main types: 1) lamps; 2) projector-type appliances (projectors); and 3) projector-type appliances (projectors).

A lamp is a light device that redistributes the light of a lamp within significant solid angles.

Lamps create a small concentration of light flux in a certain direction or do not concentrate it at all. Simply put, luminaires are designed to illuminate close or relatively close objects.

The design of the luminaire allows the installation of two or more lamps. The composition of the lighting fittings of luminaires with gas discharge lamps or LEDs may include devices for their ignition, stabilization of operation or simply power supply.

Luminaires for lighting, in contrast to signal luminaires, are usually abbreviated as "luminaires".

A spotlight is a light device that redistributes the light of a lamp within small solid angles.

The luminous flux of the spotlight is collected in a narrow beam directed strictly in a certain direction. Therefore, the purpose of a spotlight is to illuminate distant or significantly distant objects. The distance to an object illuminated by a spotlight can reach several thousand times the size of the spotlight itself.

Among the searchlights, it is necessary to single out general-purpose searchlights, search and light-signal searchlights, beacons, traffic lights and headlights.

General purpose floodlights are used for long-term illumination of working surfaces and open spaces, architectural monuments, building facades and other objects. A common name for this group is floodlights.

Searchlights are long-range searchlights and are designed for short-term illumination of very distant objects in order to detect them, they can be used as anti-aircraft searchlights, sea searchlights and other objects.

Light beacons (aerodrome, sea, river, navigation and others) signal the location of the beacon.

Signal lights are designed to transmit signals in Morse code or another system. For example, lighting fixtures for discos can be attributed to signal spotlights. Here is an example of a modern "smart" disco lighting fixture.

Traffic lights are used to transmit light signals that regulate the movement of vehicles and people.

Headlights are projector-type external lighting devices installed on vehicles to illuminate the road.

A projector is a light device that concentrates the light flux on some small surface (or in some small volume). Projectors are the lighting part of light-projecting optical devices, concentrating the light flux on the frame window, in which there is a picture or transparencies depicted by the lens on the screen (screen projectors). Technological projectors (concentrators), designed for radiant heating of objects, such as the evaporation of liquids, metal melting, and laser pumping, have also become widespread.

Screen projectors are divided into episcopes, diascopes and epidiascopes. Bishops are designed to project onto the screen surfaces that send a reflected light flux into the lens (from drawings, drawings). In diascopes, the projected surface (diapositive, film frame) sends a light flux that has passed through it into the lens. Epidiascopes can work both as episcopes and as diascopes.

Thus, the main characteristic that determines the division of lighting devices into lamps, spotlights and projectors is the degree and nature of the concentration of the light flux of the lamp in the beam of the device. In turn, all types of lighting devices can be divided into groups in accordance with the classification below.

Lighting devices are a subclass of lighting products that traditionally also combine light sources, ballasts for gas discharge lamps and LEDs, as well as lighting electrical installation products.

Additional classification of lighting devices

An additional feature of the classification of lighting devices is their division according to the types of light sources used: incandescent lamps, arc lamps, metal halide lamps, low and high pressure sodium lamps, xenon lamps, lights, flash lamps, electric arcs, LEDs and others. At the same time, further detailing on this basis is also possible, for example, luminaires for incandescent lamps for general purposes, filament lamps, luminaires for miniature incandescent lamps, lighting fixtures for luminaire lamps, and so on. Classification in this direction can be completed taking into account the standard size of the device in terms of power, lamp design (for example, in the shape of a bulb) and the number of lamps in one lamp.

Similarly, for luminaires with fluorescent lamps, we have: luminaires for conventional straight tubular fluorescent lamps, for high-intensity fluorescent lamps, for metric fluorescent lamps, for erythemal fluorescent lamps, for reflector fluorescent lamps, for annular fluorescent lamps, for U-shaped fluorescent lamps, for compact fluorescent lamps and so on.

Separate types and groups of lighting devices can be classified into long-term (constant), short-term or flashing devices; on execution for work in certain operating conditions (on temperature, humidity, concentration of dust, chemically active and explosive substances); on mechanical loads and vibrations; for protection against electric shock; by the method of power supply (network, autonomous); possible movement during operation; if possible, change the position of the optical system of the light device and other signs.

It is interesting to note that it is also possible to classify lighting devices in terms of the location of the radiation source in relation to the lighting fittings. According to this principle, lighting devices can be divided into devices with their own and with an autonomously located source of radiation (at a certain distance from the light-distributing elements, for example, lighting devices with LEDs).

It can be seen from the foregoing (although the above classification does not affect the shape, material, design features and a number of other distinguishing features of lighting devices) how wide the range of these products is. In this regard, it is not surprising that there are several thousand versions of only lamps for lighting various rooms.

Terms requiring further clarification

General lighting fixtures are called lamps designed for general lighting of rooms and open spaces.

Local lighting fixtures are lamps designed mainly for illumination of work surfaces.

Combined lighting fixtures devices that create (successively or simultaneously) both general and local lighting are called.

Stationary light fixture- a device fixed in place and requiring the use of a tool to remove it.

Non-stationary lighting device can be removed from the place of operation without the use of tools and moved from one place to another.

Portable light fixture- a non-stationary device with an individual power source or connected to the mains by a long flexible wire that is not disconnected when the light device is moved.

Division of lighting fixtures by installation method

According to the installation method, lighting fixtures are divided as follows.

Suspended light fixtures called devices for attaching to the supporting surface from below using an attachment point with a height of more than 0.1 m. In this case, a multi-lamp is called a chandelier.

Ceiling light fixture fastened to the ceiling directly or using a mount with a height of not more than 0.1 m.

Built-in light fixture is called a device for installation in a ceiling, a niche or for embedding in equipment.

Attached light fixture a light device is considered to be permanently fixed on the equipment and being its integral element (but not built into it).

wall light fixture Designed for installation on a vertical support surface.

To subgroup reference lighting fixtures include table, floor, crowning and console lamps. At the same time, support luminaires are understood to be luminaires designed for installation on the upper side of a horizontal surface or fastening to it using a rack or support. If table lamps are meant to be installed on a table or other furniture, floor lamps are meant to be installed on the floor, then a crown lamp is a reference lamp for illuminating open spaces, and a console lamp is a lamp whose light center is shifted relative to the vertical passing through the support attachment point .

Manual light fixture a portable device is called, which is connected by a flexible wire to the mains and is located in the hand during operation. At the same time, it is a portable light device, which is powered by an individual current source and is located in the hand during operation.

head light during operation is located on the head.

end light fixture Designed for installation in the tail section of vehicles.

It should be noted that the terms "sconce" (a synonym for a wall lamp), "floor lamp" (floor lamp), and "plafond" (ceiling lamp) that were previously used in a number of cases are not currently used.

The term "decorative lamp" found in the lighting literature is understood as a lamp, which is mainly a decorative element of the interior or exterior and plays a limited role in creating the necessary lighting conditions, and it is customary to call a "night lamp" a lamp that provides the possibility of orientation in the room at night.

The life of a modern person is unthinkable without the use of electricity. To date, the bulk of light sources - electric. About 15% of the total electricity generated is consumed by lighting devices. In order to reduce energy consumption, increase light output and increase the life of light sources, it is necessary to use the most economical light sources, gradually abandoning older and unreasonably energy-intensive analogues.

Lighting lamps

Consider the generally accepted classification. Based on the principles of operation of electrical appliances, the following types of incandescent lighting are distinguished, including halogen incandescent lamps and discharge lamps, as well as LED lamps, which have become increasingly popular over the past few years.

It is worth noting that electric lamps differ in shape, size, amount of energy consumed and heat transfer, service life, cost. So, let's consider the lighting in more detail and determine the advantages and disadvantages of each type.

Lamp types

Which of the lamps is the cheapest and easiest to use? This is the familiar incandescent lighting lamp - a veteran in the work of numerous household electrical appliances. Their low price and ease of use have made them popular for more than a decade. They are not afraid of temperature changes, they instantly ignite and do not contain dangerous mercury vapors.

They produce lamps of various power from 25 to True, the number of working hours for such lamps is low, only 1000, and electricity consumption is much higher than that of energy-saving counterparts. Over time, due to the vapors released during operation, the glass of the lamp becomes cloudy and loses its brightness. Therefore, they are unprofitable, and over time they are abandoned. So, in many European countries, their production and sale have been discontinued and prohibited by law.

Reflector lamps

Found their application and incandescent reflector lamps. In many ways, they resemble an ordinary incandescent lamp, the only difference is the silver-plated surface. This is used to create directional lighting at a specific point, for example, on a shop window or billboard. They are labeled R50, R63, and R80, where the number indicates the diameter. They are easy to use, equipped with a standard E14 or E27 screw base.

Fluorescent lamps

As you know, about 15% of all generated electricity is needed for the operation of lighting devices. Agree, it's a lot. To reduce this indicator, it is necessary to switch to more economical light sources. According to the current legislation, from 2014 the power of lighting lamps should not exceed 25 watts. Traditional incandescent lamps have been replaced by energy-saving fluorescent lamps, which consume five times less electricity, while the level of illumination remains the same. What are they? This is a white glass flask, coated on the inside with a phosphor and containing an inert gas with a small amount of mercury vapor. The collision of electrons with mercury vapor produces ultraviolet radiation, and this, in turn, is converted into the light that we are accustomed to seeing due to the phosphor.

The service life of such lamps is about a year, or 10,000 hours of continuous operation. But lighting lamps of this type have one significant drawback: they contain mercury. Therefore, they require very careful use and special disposal conditions. They must not be dropped or simply thrown into the trash can - after all, as you know, mercury vapor, even in small quantities, is very dangerous. In addition, getting into the air, they do not dissolve, but hang, poisoning everything around. So, the amount of mercury vapor from one broken lamp is approximately 50 mg 3 at an acceptable level of vapor concentration of 0.01 mg / m 3.

Another drawback of such lamps: the color of some of them is unpleasant for the eyes, their lighting is quite aggressive. There is a way out: when choosing a lamp, its color temperature should be taken into account. It is measured in Kelvin (K). So, a softer, warmer shade is given by lamps marked 2700K - 3000K, it is this indicator that is most optimal for human eyes when working indoors, as it is closest to natural sunlight.

Application of fluorescent lamps

Among the huge number of electric lamps, there are those whose main task is to work continuously for many hours in a row. They are used in premises of a certain type: hospitals, supermarkets, warehouses, offices. It is believed that their light is closest to natural light, hence the name: fluorescent lamps.

Lamps are produced in the form of an elongated glass tube with contact electrodes at the edges. They have also been used at home. They are used as the main source of light on the ceiling or mounted on the walls as an additional one. They are very convenient, for example, in the kitchen, above the work surface, when directional lighting is needed, or as decorative lighting in niches, under shelves and paintings, for illuminating aquariums or heating indoor plants in the cold season. They work from a conventional network and do not require special current converters. Such lamps are considered energy-saving, since compared to an old-style incandescent lamp, they practically do not heat up, consume up to 10 times less energy, and their service life is about 10,000 hours of continuous operation. But there is one caveat: such lighting is usually used indoors at a temperature of 15-25 degrees. At lower temperatures, they simply will not work. In addition to white and yellow, such lamps can emit other shades: blue, red, green, blue, ultraviolet. The choice of color depends on the purpose and scope.

Halogen lamps

To date, more than one type of lamp is used, consuming half the electricity than their predecessors. Such lamps are classified as energy-saving. These are halogen lighting lamps widely used in daily life. Due to their compact size, it is convenient to use them in lighting fixtures such as floor lamps, sconces, ceiling lamps with a non-standard shade, for decorative built-in lighting.

To fill the flask of such a lamp, a mixture of special gases with bromine or iodine vapor is used. When the device is connected to the mains, the filament (tungsten coil) heats up and glows. Unlike a conventional electric light bulb, here, when heated, tungsten does not settle on the walls of the bulb, but in combination with gas gives a brighter and longer glow, up to 4000 hours. Such lamps emit ultraviolet rays, which is very harmful to the eyes. Therefore, high-quality lamps have a special protective coating. They are very sensitive to voltage drops and can fail very quickly.

Energy-saving lamps

Today, those that use several times less energy for work are considered to be a universal and energy-efficient light source, while not reducing the power of the generated stream. As, for example, energy-saving lamps designed for residential and office premises. They are universal and can be used in lighting fixtures of various types.

Characteristics of lighting lamps of this type: electricity consumption is several times lower than that of incandescent lamps, they last up to 10 times longer, they do not heat up, they do not flicker, they do not buzz, they are quite durable and do not contain hazardous components.

Among the shortcomings, the following can be distinguished: slow warm-up (up to 2 minutes), work at a temperature not lower than 15 degrees. They cannot be used outdoors in open fixtures.

Main advantages of LEDs

But one of the most profitable in terms of energy savings are light-emitting diode or LED lamps. Translated from English LED - light emitting diode - "light emitting diode". The light output of such lamps is 60-100 Lm/W, and the average service life is 30,000-50,000 hours. At the same time, modern lighting lamps of this type do not heat up and are completely safe to use. Well, if one of the bulbs burns out, this will not affect the operation of the entire mechanism, it will continue to work.


Their color temperature is quite diverse - from soft yellow to cold white. The choice of color depends on the use of the room and the preferences of the owner. So, for example, for an office it is better to choose a bright white with a mark of 6400K, for a children's room, natural light is suitable, not so aggressive, 4200K, but for a bedroom - a slightly yellowish tint, 2700K.

And one more plus: they are deprived of the main drawback of fluorescent lamps: buzzing and flickering, and the eyes are very comfortable in such lighting. They work from a conventional 220 W network and are equipped with a standard E27 and E14 base.

The use of LEDs in everyday life

Interestingly, a dozen years ago there was not even such a thing as LED lamps for the home. Only an auto mechanic could tell how to choose and install them - after all, they were used mainly on the dashboard of a car and indicator lights. Today, their use at home has become so commonplace that we don’t even think about choosing between LED lamps and old-style lamps, the choice is so obvious and not in favor of the latter. The main point: in LED lamps, the current is a constant value, so heating costs are minimal. Consequently, they do not heat up and, like fluorescent lamps, can last for many years. Even despite their high cost, they are beneficial to use. By consuming less energy, these lamps help reduce your monthly electricity bill. By the way, when choosing LED lamps for your home, you should take into account such a difference in power. There is one secret. You need to know the power that a general purpose lighting lamp consumes and divide it by 8. For example, if you change a regular lamp at 100 W, then 100: 8 \u003d 12.5. So, you need a LED lamp with a power of 12 watts.

Another equally important indicator is that such lamps have different characteristics. This indicator determines how comfortable the lighting will be provided by the LED lighting lamp in the room. Of the existing shades of white light, the most optimal is the shade in the range of 2600-3200 K and 3700-4200 K. Such light is soft, closest to natural sunlight and pleasing to the eyes. An indicator of 6000 K gives a very cold white tint, and less than 2600 K - an oppressive yellow. Such shades are harmful to the eyes, a person gets tired quickly, headaches may appear and vision may deteriorate. Therefore, it is very important to purchase only high-quality ones, the consultant in the store will tell you, and also provide all the necessary quality certificates.

Like it or not, the LED lamp is beneficial in many ways.

It consumes several times less electricity.

It does not heat up during operation, which makes it possible to use it with flammable materials, for example, in cornices, false ceilings. A large number of such lamps do not overheat the air in the room.

Such lamps do not burn out, but over time they only lose their brightness, up to about 30%.

Long service life, up to 15 years.

So, having an idea of ​​what types of light bulbs are, knowing their main characteristics, advantages and disadvantages, you can safely go to the nearest store. But there is one more important point, without which even a simple replacement of a burned-out lamp will be impossible. After all, in order to choose a lamp for a lighting fixture, you need to know what kind of base it is. With the help of the base, the lamp is attached to the cartridge, and it is he who supplies electric current to the light bulb.

Choosing the right plinth

For the manufacture of the base, metal or ceramics are used. And inside there are contacts that transmit electric current to the working elements of the device. Each lighting fixture is equipped with one or more lamp sockets. It is important that the base of the purchased lamp matches the cartridge. Otherwise, it won't work.

Despite the variety of types of lamp bases in everyday life, two types are more often used: threaded and pin.

A screw base is also called a screw base. The name accurately conveys the way it was connected to the lamp socket. It is screwed into lighting lamps; for this, a thread is applied to its surface. The letter E is used for marking. This type is used in many types of lamps in household appliances. These plinths vary in size. So, when marking the base, after the Latin letter E, the manufacturer must indicate the diameter of the threaded connection. In everyday life, plinths of two sizes are most often used - E14 and E27. But there are also more powerful lighting lamps, for example, for street lighting. They use an E40 base. The size of threaded connections has remained unchanged for many decades. Even now, you can easily replace a burnt-out ordinary light bulb in an old chandelier with a more economical, LED one. The dimensions of the base and the cartridge are exactly the same. But in America and Canada, other parameters are adopted. Since their mains voltage is 110V, in order to avoid the use of European-style light bulbs, the base diameter is different: E12, E17, E26 and E39.

Another type of socles used in everyday life is a pin. It is attached to the cartridge with two metal pins. They act as contacts that transmit electricity to the light bulb. The pins differ in diameter and distance between them. For marking, the Latin letter G is used, followed by a digital designation of the gap between the pins. These are G9 and G13.

Now you can safely proceed to the repair. And although the redevelopment or construction of new walls can only be done by specialists, you can handle the choice and replacement of electric lamps on your own.

Lighting. Basic concepts and characteristics.

Devices that redistribute the luminous flux of light sources in space in the required way are called Lighting Devices (OL).

All OP can be conditionally divided into the following groups:

  • lamps.
  • spotlights.
  • projectors.

Luminaires are luminaires in which the luminous flux from light sources is distributed within large solid angles. As a rule, lamps illuminate objects that are at fairly close distances from them, commensurate with the size of the lamps themselves. Luminaires can illuminate surfaces and objects both indoors and outdoors.

Searchlights are OPs that focus the light flux from light sources in fairly small solid angles and illuminate objects located at distances from the OP that are much greater than the size of the OP itself. Floodlights, as a rule, illuminate objects outside the premises.

Projectors are OPs that concentrate the luminous flux of a light source on a certain clearly defined area or in a certain volume. A well-known type of projector is a movie projector. Such an OP creates a given illumination only on a certain area of ​​the screen. As a rule, projectors use complex optical systems that provide not only the necessary levels and uniformity of illumination over the entire given surface, but also the extremely clear transmission of image projection from one place to another with a change in scale.

Lighting parameters

The main lighting characteristics of lighting devices are the luminous intensity curves, the ratio of the flows radiated into the lower and upper hemispheres, and the efficiency.

From how the luminous flux of the device is distributed in space, its purpose in lighting depends. The light distribution is evaluated using the so-called luminous intensity curve.

The luminous intensity curve (KCC) is a graphic representation of the distribution of light in space, represented as a graph I (a, b), where a and b are the angles of propagation of the light flux in the longitudinal and transverse planes. The more it resembles an oval stretched along the vertical axis of the light device, the narrower the curve is considered and the higher the illumination in the center of the light spot. The shape of this curve is the most important characteristic of a lighting device.

Lighting devices are divided into 7 types according to typical luminous intensity curves:

  • Concentrated (K)
  • Deep (G)
  • Cosine (D)
  • Semi-wide (L)
  • Wide (W)
  • Uniform (M)
  • Sinus (C)

Typical luminous intensity curves (in cd) of a luminaire are calculated for the value of luminous intensity with a lamp luminous flux Fcv = 1000 lm. The main feature that determines the type of curve is the ratio of the maximum luminous intensity of the lamp to the arithmetic mean for a given plane.

Lighting devices are divided into classes, depending on what proportion of the total lamp flux is the luminous flux of the lower hemisphere. The flow in space can be distributed mainly downwards (direct light fixtures), predominantly upwards (reflected light fixtures), evenly in all directions (diffused light fixtures).

Diffused light fixtures are suitable for general lighting. They are distinguished by a uniform distribution of light brightness, soft shadow-forming properties and saturation of the surrounding space with light, which is important for creating visual comfort.

Reflected light fixtures provide the most comfortable and uniform lighting, fully compliant with glare and discomfort limits, good light saturation, combined with overhead or side daylight.

Direct light fixtures are mainly designed for rooms with low ceilings. As a rule, these are ordinary ceiling-mounted or ceiling-mounted appliances. They are economical when providing localized lighting for reading and work, or when illuminating paintings, sculptures, etc.

Depending on the proportion of the luminous flux falling on the lower hemisphere, lighting devices are divided into 5 classes:

Direct light, if this proportion is more than 80% (P);

Mostly direct (60...80%) (N);

Scattered (40...60%) (P);

Mainly reflected (20...40%) (B);

Reflected (less than 20%) (O).

These parameters are indicated by the manufacturer in the accompanying documents for the OP.

Classification of lighting fixtures according to their main purpose

According to the main purpose, OPs are divided into the following groups:

  • OP for lighting industrial premises;
  • OP for lighting administrative, office and other public premises;
  • OP for lighting household premises;
  • OP for lighting agricultural premises;
  • OP for lighting sports facilities;
  • OP for functional outdoor lighting;
  • OP for decorative outdoor lighting;
  • OP for internal lighting of means of transport;
  • OP for architectural and artistic lighting of buildings, structures, monuments, fountains, etc.;
  • OP emergency lighting.

The classification of EPs according to their main purpose determines the preferential areas of their application. However, this classification is rather arbitrary, since often the same lamp can be used in a variety of situations.

Classification of lighting fixtures by design

According to the installation method, OPs are divided into the following groups (according to GOST 17677):

  • embedded (B);
  • ceiling (P);
  • suspended (C);
  • wall (B);
  • floor (T);
  • desktop (H);
  • crowning (T);
  • console (K);
  • portable (P).

The design feature sets the predominant position of the luminaire in space in terms of obtaining the greatest effect and achieving the results declared by the manufacturer.

Electrical lighting fixtures consist of:

  • light source,
  • fastening (electrocontact) fittings,
  • reflector (diffuser) of the light flux.

Electric lamps of various designs can be used as a light source, as an alternative to them, LED lighting is increasingly being used, where the light source is semiconductor elements - LEDs.

Despite the variety of designs and principles of operation, light sources have a number of common characteristics, which, along with the supply voltage, include:

  • light flow,
  • light output,
  • illumination,
  • color temperature,
  • color transfer.

PARAMETERS AND CHARACTERISTICS OF LIGHTING DEVICES

Here are listed and will be considered the parameters of practical interest for the choice of a particular lighting device or light source.

Light flow- this is the power of light (optical) radiation, measured in lumens (lm). Omitting theoretical calculations and definitions, I will say at a purely everyday level - this is the amount of light emitted by the source, the larger it is, the brighter the light. What has been said is very abstract, so far we cannot derive any benefit from this, so let's move on.

Light output. Determines the ability of a light source to convert electrical energy into light energy, measured in lumens / watt (lm / W), being essentially an efficiency factor.

An ideal source is capable of delivering 683 lm / W, in practice this value is naturally less. For incandescent lamps, for example, the luminous efficiency is 10-15, fluorescent lamps up to 75, high-power LEDs more than 100 lm / W.

It's already something. Since everyone is well aware of the 100 W incandescent lamp, they can now imagine the 1200 lm luminous flux that it emits. In addition, this indicator allows you to evaluate the level of energy saving. Obviously, with the same light output, a fluorescent lamp consumes 4-5 times less electrical energy than an incandescent lamp.

illumination. This parameter characterizes the amount of luminous flux per unit area. It is measured in lux (lx). 1lx=1lm/1m2 Illumination depends on the design of the reflector, the distance to the light source, and their number. For evaluation - normal illumination for reading is 500 lux. Illumination on a sunny summer day at the latitude of Moscow can reach 100,000 lux, and on a full moon - up to 0.5 lux.

Colorful temperature. Radiation of a certain color is characterized by a wavelength. Visible radiation of red color has the smallest wavelength, blue - the longest. If we simplify to the limit, then the color temperature characterizes the color of the radiation. It's very primitive, but that's enough for us. It is measured in degrees Kelvin (0 K). Again, an example of how light of different temperatures is visually perceived:

  • warm white - about 3000-3300 0 K,
  • neutral white - 3300-5000 0 K,
  • cold white - more than 5000 0 K.

Color rendering index Ra. It is an indicator of the naturalness of perceived colors. The greater the value of this index is the lighting device (light source), the better the color rendering. A color rendering index of 70-100 characterizes color rendering from good (70) to excellent (90-100).

© 2012-2020 All rights reserved.

The materials presented on the site are for informational purposes only and cannot be used as guidelines and normative documents.


Lighting

photo flash
Flashlight(pulse photo illuminator, IFO) - a lamp with which instant illumination of the subject is carried out when photographing.
The main element of a modern photo flash is a pulsed discharge lamp. A pulse gas discharge lamp is a sealed glass tube, straight, spiral, arcuate or annular, filled with xenon. Electrodes are soldered into the ends of the tube, and on the outside there is an ignition electrode, which is a strip of conductive mastic or a piece of wire. A spark discharge in a lamp occurs when its electrodes are connected to a relatively powerful source of high voltage (hundreds of volts), usually an electric capacitor that accumulates an electric charge in the interval between flashes, and a high-voltage (about thousands of volts) pulse is applied to the ignition electrode from a pulse transformer, which ionizes the gas in the tube, allowing the charge accumulated in the working capacitor to be discharged. During the discharge, accompanied by an intense flash of light with a light intensity of several hundred thousand candles, the voltage across the capacitor drops and the discharge stops. After that, the capacitor in conventional flash lamp power circuits is charged again and when a pulse is applied to the ignition electrode again, the lamp can give the next flash.
There are (and were widely used earlier) chemical photoflashes. The most common type was magnesium.
According to the signs of automation, flash units are divided into:
non-automatic, giving a predetermined amount of light
automatic, measuring illumination with its own sensor, or with a sensor located in the camera (eng. TTL, Through The Lens, - through the lens)
automatic, measuring illumination during the main pulse or according to a preliminary, evaluation pulse (E-TTL, English evaluative - evaluation).
When it is possible to work with cameras from different manufacturers, flash units are divided as follows:
System, that is, suitable only for cameras of one particular company (system). These flashes typically allow TTL and/or E-TTL (P-TTL, S-TTL, i-TTL, D-TTL, etc. depending on the system.) light metering, as well as other advanced features.
Universal flashes with one central contact are relatively inexpensive and widely used, however, it is necessary to carefully read the instructions for such a flash before installing it on the camera - many of them are built according to high-voltage switching circuits and such flashes cannot be placed on modern cameras to avoid damaging the electronics device with high voltage, but only on cameras with a mechanical shutter. As a rule, the power of such flashes is controlled by a photosensitive element in the flash itself.
There are also universal flashes with a special connector, which can be connected to a camera of a certain manufacturer through a special system adapter.
According to the location in relation to the camera, flashes are:
built into the camera. They are usually not very powerful, due to the proximity to the axis of the lens they give a “flat” image, almost without shadows, they do not highlight the structure well. Their main advantage is that they are always with the camera and practically do not increase the dimensions and weight of the camera. They are also very good to use when shooting on a bright sunny day, to highlight harsh shadows from sunlight. The closer to the optical axis, the more pronounced the red-eye effect. In this case, it is maximum.
Attached to the camera. They are usually more powerful than built-in ones. They also give a flat image with sharp little shadows. Many, however, have the ability to turn the head up (and some also to the side), so that you can point the flash not directly at the subject, but at a white ceiling, or a reflective screen, and get more natural-like lighting. It also reduces the red-eye effect.
Flashes not attached to the camera. They make it possible to flexibly change the lighting conditions depending on the intentions of the photographer. For example, to get soft lighting, you can point the flash not directly at the subject, but at a white ceiling, or a reflective screen, and get more natural-like lighting. Such flashes are controlled either through a cable connection to the camera, or wirelessly (IR, flash control, radio). In this way, several flashes can be controlled simultaneously, it becomes possible to illuminate the object from different angles and creates better lighting conditions compared to other flashes.
Macro flares. For macro photography, flashes are used in the form of a ring or a paired system of flashes on brackets that are mounted on the lens. Flashes attached to the camera for macro photography are ineffective: the lens blocks the flash.
For wireless control options:
Able to work in both master and slave modes. They are found both among systemic and among universal ones. The former allow you to control (and can be controlled) various advanced features - pulse power, create groups of flashes with different control channels, measure the illumination of the subject; the latter simply fire on the impulse of the master flash.
Able to work only in slave mode - as a rule, these are medium-level system flashes. However, in manual mode (without using a pre-flash), they can be used as a master for universal flash units.
Able to work only leading. These are either specialized system control flashes that give a control IR pulse, but do not give the main flash, or the simplest flashes that can trigger slave (universal) flashes with their main pulse.
In some cases, a strobe is used as a flash (some flashes can work in this mode with a decrease in pulse power) with a long open shutter and low ambient light. This type of shooting is used when it is necessary to capture the phases of the movement of the subject in the picture (for example, how a cat falls on its paws).
Options
The main characteristic is the guide number, the distance at which normal illumination is achieved with a film sensitivity of 130 units. GOST (140 ISO; 22-23 DIN; 110 Weston; 180 General Electric) and aperture number 1.

When the film speed is doubled, the guide number changes by a factor of 1.4 (square root of 2).
Calculation example
Initial data
Guide number: 24
Film: 800 units ISO
Distance: 15 m
Recalculation of the leading number:
Closest standard aperture value: 4
Typically, non-automatic flash units have either a table on the back wall to simplify calculations, or a simple mechanical aperture calculator, arranged according to the principle of an adding machine. More sophisticated flashes may also have an automatic aperture calculator, the results of which are displayed on the built-in LCD screen.
Application
Insufficient light is the most common (albeit the most unfortunate) use of a flash. In this case, the flash usually illuminates the subject from the side of the camera, and therefore the image is “flat”, the structure and relief stand out weakly. Moving the flash away from the camera does not solve the problem, because although relief and shadows appear, the shadows are usually very sharp and deep, with poor detail. These pictures look very unprofessional. Sometimes it saves the day if there is a bright reflective surface close to the subject (sometimes you can use the ceiling), and then the light from the flash, reflected from this surface, can create a softer key light.
Highlighting shadows - if the shooting is carried out on a bright sunny day, then very contrasting deep shadows are obtained. Using the flash to highlight the shadows softens the shadows and makes the image softer. In this case, you need to be careful if the camera has a focal shutter, and in bright sunlight, the exposure time may turn out to be such that the shutter does not open completely (for example, a slit moves in a curtain-slit shutter at short shutter speeds) - then it is impossible to shoot with a flash, since the flash light will only hit part of the picture. Some modern flares compensate for this by producing a large number of weak pulses.
When shooting against bright backlight (for example, a person in a room against a bright window), the flash allows you to highlight the foreground.
Sports and reportage photography. When shooting fast-moving subjects, the flash allows you to shoot at very fast shutter speeds (if the shutter type allows you to shoot at such shutter speeds with flash). This helps to combat "blurring" of fast moving objects.
When shooting in the studio, combined illuminators are used, consisting of a powerful flash and a source of constant “modeling” light, which allows the photographer to evaluate the future lighting pattern.

exposure meters
Exponometer(Latin expono) - a device, fixture or table for calculating exposure parameters (exposure time and aperture value) in photography and cinema.
Exposure meters are divided by type of device into:
Tabular
They are a table that describes the shooting conditions and the corresponding parameters. They have practical meaning only if the photographic latitude of the photographic material used is sufficiently large. They are also used in the form of setting the exposure according to weather symbols on scale cameras (“Smena-Symbol”, “Agat-18”).
Optical
Devices in which the main comparing element is the human eye.

Reading the exposure time or the aperture number is made by visual comparison of the brightness of the corresponding figures with the brightness of the optical wedge of variable density. The main disadvantage is the dependence of the eye sensitivity on the total ambient illumination, which can lead to large errors. Now they are practically not used ("Optek").
Equalizing the brightness of two comparison fields, one from the measured scene or light source, the second from the reference lamp. Finds application in image copying systems.
photoelectronic
The flow of light is perceived by an electronic photocell, and the required value is read from the scale by the deviation of the arrow or from a digital indicator.
In turn, they can be divided into:
selenium
Devices using photodiodes based on a selenium photocell - do not require batteries (the necessary EMF is generated by a photocell), have the simplest electrical circuit, but have low sensitivity and irreversibly degrade when exposed to too bright light flux (increases error); (Exposure meters "Leningrad-1,2,4,7,8,10", exposure meters on cameras "Kyiv-3,4", on some Zeniths and FEDs).
photoresistor
Devices using photoresistors as a sensor, and in some cases photodiodes in reverse current mode. The simplest circuit of such a light meter is based on the bridge principle, and the resistance of the sensor is compared with the reference ones switched by the shutter speed and aperture calculator. The indicator is a galvanometer showing the direction of rotation of the shutter speed calculator. More complex circuits with active elements (transistors) became more widespread, LEDs began to be used as an indicator to increase mechanical reliability, and the calculator is usually associated with a variable resistor. ("Sverdlovsk-2" and "Sverdlovsk-4"). They have the best sensitivity and linearity characteristics, low consumption.
Digital
They usually contain the same sensor as the photoresistor ones, however, the signal from it is digitized and further processed by a microprocessor device. They have more flexibility and range of measurement capabilities, but significantly higher battery consumption.
Devices that measure illumination (the amount of light falling on an object) or brightness (the amount of light reflected from an object), and the brightness meters are divided according to the measuring angle into devices that have a large measuring angle (about 45 degrees), and narrowly focused - spotmeters(English spot - spot) with an angle of about 1 degree, and are considered the most professional.
Similar devices.
A device similar to a light meter - flashmeter used to measure the amount of light when shooting with a flash. Flashmeters can measure both incident and reflected light. Since flash exposure has little effect on the amount of light reaching the photosensitive material, only the aperture value is determined by the flashmeter. The shutter speed is usually set to the sync speed value, which is determined by the design of the shutter.
More versatile instrument multimeter- incorporating the possibilities, as well as being able to combine them, from an exposure meter and a flash meter - to work, respectively, with constant, pulsed, and also mixed lighting.

Literature
1. Exposure meter // Photo-cinema technique: Encyclopedia / Editor-in-chief E. A. Iofis. - M.: Soviet Encyclopedia, 1981.
2. Yashtold-Govorko V. A. Photography and processing. Shooting, formulas, terms, recipes. Ed. 4th, abbr. M., "Art", 1977.
3. Directory of amateur photographer. - M.: Art, 1961.
etc.................