Brightness
The standard brightness of the on-camera light (see "Type"). Usually, most of these models have the ability to adjust the brightness, so the maximum value is given in the specifications.
When shooting at a short distance, devices that are too bright can “overexpose” the scene, degrading the quality of the shooting (and it can be much more difficult to compensate for excessive brightness in post-processing than the lack of light). So when choosing for this indicator, it is worth proceeding from the specific conditions of use.
Number of diodes
The number of light-emitting diodes (LED) provided in the on-camera light system (see "Type").
The abundance of LEDs allows you to achieve good brightness at a relatively low cost of the entire device — there are many light sources themselves, but they are relatively cheap. However, these models can be inconvenient to carry on camera and work in tight spaces. In turn, compact lamps with a small number of LEDs are more convenient, portable and "manoeuvrable", however, they are either inferior to more "multiply charged" models in terms of brightness, or are noticeably more expensive.
Illumination angle
The angle of illumination provided by the on-camera light source (see "Type").
A large illumination angle, on the one hand, allows you to simultaneously cover a larger area, which is especially important when shooting long shots (at short focal lengths). On the other hand, to achieve sufficient brightness, this requires a large power of light sources, which accordingly affects the price and power consumption of the device. A small coverage angle, in turn, gives a small spot size of the light, but it allows you to achieve good brightness at a relatively low power.
Colour temperature
The colour temperature of the light emitted by the device. Most of the classic flashes have a standard colour temperature of 5500-5600 K, so this parameter is usually not given for such lamps. But on-camera light sources (see "Type") can differ markedly in this indicator, and we will talk about them.
Colour temperature characterizes the overall shade of the glow emitted by the device. At the same time, an interesting nuance is that low values \u200b\u200bcorrespond to colours that a person perceives as warm; and as the colour temperature rises, the hue shifts more and more towards cool colours. For example, for a 60 W incandescent lamp, the light of which has a pronounced yellowish colour, this parameter is approximately 2700 K, and for a fluorescent lamp that produces “daylight” light with a bluish tint, this parameter is about 7000 K.
In general, the colour temperature of lighting is one of the most important parameters when shooting: it determines the colour balance of the image "seen" by the camera. In camera settings, this indicator is called "white balance". It can also be determined automatically, however, for the most reliable colour reproduction, it is still desirable to set its values according to the known colour temperature of the lighting.
Specifically, in on-camera light sources, the colour temperature can be either constant or adjustable. In non-adjustable models, the value of this parameter is the same as in most flash units...— 5500 K, which corresponds approximately to neutral white. Adjustment also provides the possibility of at least lowering the colour temperature — usually up to 3200 K, which approximately corresponds to warm white light. In addition, occasionally there are models in which the maximum colour temperature exceeds 5500 K, reaching 6000 K and even more.
The ability to change the colour temperature can be useful not only for shooting as such, but also for “matching” the lamp with other light sources. The fact is that if several simultaneously used light sources have different colour temperatures, the colour rendition on the scene being shot will be unreliable — to the point that a monochromatic object illuminated by different lamps from different sides may look like a two-colour one. One way to avoid this is to set the colour temperature of the on-camera light to match the ambient light. However, it is worth noting here that the methods of adjusting the shades and the accuracy of such adjustment may be different. The most advanced option is to use two sets of LEDs, with a warm and cold shade of glow; By changing the brightness ratio between these sets, you can also change the overall colour temperature — and quite smoothly and accurately. Another way is to use coloured diffusers (see below), but here the adjustment is stepped, with fixed values (with and without a diffuser). In some devices, both of these methods are combined.
Features
—
Autofocus illuminator. The flash has an auxiliary illumination function for the camera's autofocus system. Modern cameras overwhelmingly use the so-called passive autofocus systems that have one serious drawback: very low efficiency in low light and/or low contrast of the object being shot. The autofocus illuminator is designed to solve this problem: before focus, the scene is illuminated by a separate lamp, placed, in this case, directly in the flash body. This provides enough light for normal autofocus operation. Most often, backlight lamps give light with a characteristic reddish tint, however, in some advanced models, infrared illumination is used — invisible to the eye, but perceived by the camera. In addition, illumination systems can use a special light pattern instead of a solid beam, which further simplifies the task of autofocus systems. Anyway, the presence of this function is especially relevant given the fact that the flash is often used as a light source in low light.
— Control on the camera. The ability to change the settings for the flash using the controls of the camera itself, to which it is connected. In some cases (for example, with a wireless connection), this is much more convenient than switching attention from the camera to the flash.
—
Automatic zoom. The ability to automatically change the angle of dispersion of the flash light. For the angle of dispersion,
...see the relevant paragraph above, but here we note that this function provides synchronization between the flash and the lens: when the focal length of the lens changes, the angle of dispersion automatically changes. This provides the most effective illumination of the scene and at the same time relieves you of the need to manually re-adjust the flash to a changed angle of view each time.
— Manual zoom. Possibility to change the flash spread angle (see "Light spread angle") manually. This function expands the possibilities for "fine" tuning of work parameters and allows you to set parameters that are not available with automatic zoom (see above). In addition, it will be useful if you have to use several prime lenses with different focal lengths — the flash can be easily adjusted to each of them.
— Wireless control. Ability to wirelessly connect the flash to the camera or to another flash as master/slave (if available, see below). The format and specific features of such a connection may be different: wired connection, IR channel, radio, etc. Wireless control is indispensable if the flash must be placed away from the camera; it also makes it easier to create multiple flash systems for optimum lighting. These features are especially useful for studio shooting (although it's not limited to this).
— Work in master mode. The ability to operate the flash as a master flash for a system of multiple flashes. The entire system is controlled through the master flash, the operation parameters of the slave flashes are set, and the command to fire is given (note that the master flash itself may not fire at all). If you plan to shoot using a multi-flash system, you will definitely need a model with this function — without it, creating a system is impossible. Of course, master and slave flashes must be mutually compatible; this point should be clarified separately.
— Work in slave mode. The ability to work as a flash as a slave in a system of several flashes. In this mode, the device is connected to the master flash and fires on command from it. For more information on flash systems, see "Master Operation" above.
— Diffuser. The colour of the diffuser supplied with the on-camera light source (see "Type"). Colour can be: orange, white, pink or yellow.
A diffuser is a special filter designed to scatter light from individual LEDs, and also, in some cases, to give it a certain colour and change the colour temperature.
— Radio synchronizer. A device designed to wirelessly control a flash or a set of flashes (if each has its own receiver). Usually a separate module installed in the hot shoe; on command to fire, this module sends a radio signal to all receivers tuned to it, ensuring synchronous flash firing. At the same time, some models of luminaires with such a function are capable of receiving via the radio channel not only the start signal, but also the operating parameters (primarily the duration and power of the pulse).Screen
The flash has its own built-in
display. This feature greatly simplifies management and even provides a number of additional features. Various service information can be displayed on the display — from a simple display of various parameters (pulse duration, scattering angles, etc.) and ending with data from special calculators that provide the calculation of optimal shooting parameters.
