In this case, light is emitted in short pulses, the duration of which does not exceed 1/500 sec. Flashes are built-in and external. The former are built directly into the camera body (most models are equipped with this option) and are actually an auxiliary tool with low power. The built-in flash is useful in poor lighting, however, due to the location (as close as possible to the optical axis), it can cause sharp contrasting borders, light spots, and red-eye. Some camera models allow you to change the direction of the light output of the built-in flash, in some cases this can be useful.

But to improve the quality of pictures, you need to purchase an external flash. Unless, of course, your camera allows you to connect it - that is, it is equipped with a "hot shoe". Most "soap" and some "mirrorless" cameras do not have this option.

External flashes can be divided into three main types:
Compact unmanaged flash units. These are small and inexpensive models, usually with a constant pulse power. In essence, they are not much different from built-in models, most often only with increased power. It is better to refuse to purchase such solutions altogether.

Compact controllable flash units. The most common type, providing the ability to control the pulse power in automatic and manual modes. Often equipped with various additional options and modes. This class includes both mid-level models and professional solutions.

Studio flares. Professional models used in studio photography. They are distinguished by high power ratings, advanced manual settings, and allow you to connect additional equipment. Often, an electrical network is used as a power source.

It should be noted that an external flash is not always attached directly to the camera. It can also be used on its own. In this case, the interaction between devices can be both wired and wireless. If necessary, you can use several flashes at once, illuminating the subject from several angles and achieving the best lighting conditions.

Separately, we should also talk about flashes for macro photography. They are designed to illuminate nearby objects. As a result, their power is low, and the design is unusual - often such a flash is made in the form of a ring worn on the lens. A regular flash is not suitable for this purpose, since it is blocked by the lens.

Basic flash settings

When choosing a flash, there are several main criteria to consider: guide number, flash energy, beam angle, recycling time, and synchronization with the camera. Each of them can have a significant impact on the result.

The guide number is a parameter that indicates the maximum distance from the subject to the flash in metres (at ISO 100 and aperture = 1). The guide number is one of the most important indicators that directly affects the flash energy. However, it does not always make sense to chase high performance. It has to be based on your requirements.

The recharge time indicates how quickly the energy needed to reproduce the pulse accumulates in the capacitor. This parameter is very important when carrying out reportage filming. The faster the recharge, the more shots can be taken in a given period of time.

Beam angle and auto zoom. Ideally, the angle of light scattering should coincide with the angle of view of the lens, then it will be possible to achieve a good level of illumination of the object. If the angle of light scattering is too small, darkening will appear at the edges of the picture. Auto zoom is the flash's ability to respond to changes in focal length. This is achieved through the use of a special movable lens in front of the light source. Having an auto zoom can greatly increase the cost of a flash.

TTL (Through-The-Lens) is the name of the technology of automatic power adjustment. The flash itself measures the desired exposure, which can be very useful for a beginner. Various manufacturers often use their own developments to improve TTL (E-TTL for Canon, i-TTL for Nikon).

Swivel head. The ability to change the direction of the light flux is an important option. With it, the photographer has the opportunity to change the illumination of the object, getting different results.

Power type. The flash can work both from batteries and from a special accumulator. There is no fundamental difference here. Instead of batteries, you can also use batteries of the appropriate form factor. The advantage of batteries is that they can be bought everywhere, which is sometimes useful when it is not possible to charge the battery.

Here it should also be mentioned about the type of light source. Modern flashes can be divided into two main types: xenon and LED. The first ones are more bright and powerful, but they drain the battery faster. The second ones are less powerful, but they do not drain the battery that way. LEDs are usually built-in flashes or macro solutions. Mobile devices are also often equipped with LED flashes. But anyway, whether batteries or a rechargeable battery are used, the main thing is that such a flash does not put additional load on the battery of the camera itself.

Only general parameters are listed here, which are specific to various flashes, regardless of their manufacturer. This knowledge will be quite enough for a beginner who is just learning how to use flash. In fact, many advanced models sometimes differ in a significant set of various parameters and options, the use of which requires additional knowledge and some practice.

Thus, the choice of flash depends largely on what kind of shooting you plan to produce. So, if a small guide number and a rotary head are quite enough for shooting still lifes, then such a parameter as reload time can also be a key parameter for reportage shooting. Well, a macro flash is useful, respectively, for shooting various small objects.