Type
— Regular. Classic external flash. Typically installed in the camera's hot shoe. This is a universal type of flash that is suitable for a variety of shooting types, from portraits to shooting objects at long focal lengths.
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Macro. Special flashes are intended for use when photographing objects at a short distance (macro photography). Such flashes are usually made in the form of a ring and are attached to the front part of the lens, which allows for uniform illumination of the object being photographed. Connection occurs through the camera's "hot shoe". It is worth noting that such flashes are not intended for regular shooting due to their low power.
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On-camera light can be described as an analogue of a photo flash, used mainly when shooting video. Hence another popular name for such devices — "video flashes". However, this name is not entirely correct due to the fact that on-camera light does not work in pulses, but in a constant mode. Simply put, it is a specialized spotlight attached to the camera.
Camera compatibility
Camera models that the flash can work with. Note that this parameter is usually indicated in the characteristics very approximately — only camera manufacturers are named, but there is no talk of models as such. Therefore, before purchasing a flash, it makes sense to separately clarify whether it will work normally with your camera — for example, on the manufacturer's website or thematic forums. This is especially true for devices from third-party manufacturers — for such models, the likelihood of problems is somewhat higher than for “native” flash cameras. At the same time, devices from the same company usually have the same requirements for connecting flashes, and therefore this parameter is with a fairly high degree of accuracy allows you to evaluate compatibility.
If the specifications of the flash indicate compatibility with several brands of cameras, this usually means that this model is available in several variations, each of which is designed for a different manufacturer.
It is worth noting that the "non-native" camera and flash may be quite compatible and work fine in most shooting modes. Nevertheless, support for TTL (see below) and a number of other specific functions in this case is usually out of the question, and in general, the reliability and efficiency of this combination is lower than that of a camera with a "native" flash. Therefore, it is better to choose all the same accessories with directly claimed compatibility.
Of t
...he compatible cameras currently in use: Canon, Fuji, Leica, Nikon, Olympus, Panasonic, Pentax, Samsung, Sigma, Sony.Guide number
The guide number is the main characteristic that describes the power of the light pulse of the flash. It is described as the maximum distance (in metres) at which, at ISO 100 and f/1 lens speed (aperture 1), a flash is able to illuminate an "average" subject sufficiently for a normal exposure; in other words, at what distance from the flash it will be possible to normally shoot the scene at the specified ISO and aperture.
There are formulas by which, knowing the guide number, you can derive the practical shooting distance for each specific value of sensitivity and aperture. The simplest formula used to calculate the distance at ISO 100 is: S=N/f, where S is the distance, N is the guide number, f is the aperture value. For example, for a guide number of 56 and an f/2.8 lens, this distance would be 56/2.8 = 20 m. Increasing or decreasing sensitivity by a factor of 2 would increase or decrease the specified distance by approximately 1.4 times, respectively. If you need to calculate the distance as accurately as possible, you should refer to more detailed formulas that can be found in specialized sources.
Separately, it is worth noting that the leading numbers of flashes, usually, are indicated by manufacturers for specific focal lengths of lenses. This is due to the fact that the shorter the focal length and, accordingly, the wider the viewing angle, the more light is needed to illuminate the scene being shot and the more powerful the flash pulse should b...e (at the same distance). Therefore, when choosing by the guide number, it makes sense to pay attention to the focal length indicated by the manufacturer and select a model with a power reserve — especially since guide numbers are often prescribed for rather “long-range” lenses (with a focal length of about 80-100 mm in equiv. 35 mm).
Pulse duration
The duration of the pulse of light provided by the flash. This indicator can range from thousandths to hundred thousandths of a second; it is usually expressed as a fractional number with a unit in the numerator, such as 1/880 s. The human eye does not notice the difference, but in some shooting modes it can become critical. For example, to capture fast-moving scenes (such as splashing water, the flight of an insect, or the movement of machine parts) you need to choose a flash with the shortest flash duration possible — otherwise the image may be blurry.
The longest pulse duration in modern photoflashes is about 1/800 s; the minimum value can reach 1/30,000 s or even less.
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.
TTL
Flash units with TTL support. TTL is an abbreviation for "through the lens", i.e. "through the lens"; this is the name of the method of measuring exposure by the amount of light that passes directly through the camera lens.
In digital photography, TTL works like a pre-flash: before the main exposure, the flash fires one or more test flashes. The amount of light coming from the object being filmed is measured by special sensors, based on these data, the control electronics sets the necessary shooting parameters, after which the actual exposure takes place. This allows you to fine-tune the camera and get an image of optimal quality. The interval between the test and operating pulses is so small that it may not be visible to the naked eye at all (especially when the flash is synchronized with the front curtain or with a slow shutter speed).
Many modern camera manufacturers have their own developments and varieties of TTL technology, respectively, differing in name: for example, Canon has E-TTL and E-TTL II, Nikon has D-TTL (in early models) and i-TTL (in later ones) , Pentax has P-TTL, etc. Support for one or another variety is directly related to the compatibility of the flash with cameras (see above), and different formats are usually not compatible with each other.
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.