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.
Power dissipation
Dissipated power of the on-camera light source (see "Type"). For traditional pulse flashes, this parameter is not indicated due to irrelevance.
Dissipated power describes the amount of energy that, during operation of a luminaire, is not spent on light radiation, but is dissipated in the surrounding air in the form of heat. Simply put, we are talking about the heat dissipation of the device. Although most modern LEDs are very energy efficient, it is still impossible to achieve 100% efficiency in them — some part of the energy inevitably goes to heat; and given that the number of LEDs in modern on-camera light sources can reach several hundred, then the heat release can be quite noticeable — at the level of tens of watts.
First of all, the overall efficiency of the device depends on this indicator: with equal brightness values \u200b\u200b(see above), a model with a higher power dissipation will inevitably consume more energy. In addition, high heat dissipation may require special cooling systems — including active, using fans; and this further increases energy consumption, and also affects the price, weight, dimensions and noise level generated by the lamp. However, in most cases, these points do not play a special role, and it is worth looking specifically for an on-camera lamp with a minimum power dissipation if efficiency and low heat generation are fundamental to you.
