LED lights Optional: please pay attention to three key factors

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(Free-Press-Release.com) November 30, 2011 -- LED lights as energy saving, environmental protection, high efficiency, long life, etc., are sought after more and more television people. For professional photographers and DV enthusiasts, choose a high-quality LED lighting is essential, its greatest extent, a solution must take the problem of insufficient ambient light. Present everywhere in the domestic market, domestic production of various brands of LED lighting, uneven quality, often make it difficult for photography enthusiasts, here's some of my feelings and experiences to share with you.

First: selection factors: light ball

First, LED lights the key is to look at its use of light ball, light ball determines the efficiency and brightness of LED lights.

Common one is very common on the market visible LED lights. It is composed of many small light balls, each of these small light ball power less than 1 watt, the cost is very low, and the brightness is not enough. Especially in the studio or on-site interview with the play of light is very uneven, some are in a bright light, but there is no exposure to light will cast a shadow at the interval. So that when the light hit the object, there will be that there are dark, unevenly distributed.

Another effect we usually call it the big, high-brightness LED ball. This is not only the brightness of light ball than ordinary LED light ball off a lot, but also relatively large volume and multi-effects, usually from 1 watt to 3 watts. As the production of this light needs a relatively high level of technology, the price is higher than the small light ball, the effect is relatively good.


Second: selection factors: the drive circuit

The LED lights, the other most important factor was undoubtedly the driving circuit. Consensus now is that constant current LED light source driver is the best drive. In this manner, to avoid the LED forward voltage due to changes caused by the current changes, and constant current LED brightness and stability is a major factor, so the constant current source driver has been used for most LED manufacturers. However, constant-current source and drive it very easy to do, LED manufacturers need to be controlled to achieve constant current drive circuit.

The current control circuit divided analog and digital circuitry, analog circuitry in the control current size of the battery will be affected. In other words, when the battery power is sufficient, the current large, the brightness of the light will be brighter, the color temperature will be accurate. Conversely when the battery power is low, the light will be dim obviously, a lot of color temperature difference, and some LED lights will be flickering ball phenomenon.

Compared with analog circuits, digital circuits would be much better, even if the power instability, but also make the current constant, we are most worried about is the lighting before the stability of flickering is taboo photography , I have observed in the field of LED lights change, the naked eye was barely visible.

In the later samples taken daily during the playback and can not see the lights were flickering, can be said that digital circuits can be truly realized only constant-current drive, and only digital circuits in order to truly ensure the LED light brightness and color temperature to ensure the use of in the recording process can take high quality images.


Third: selection factors: heat

In addition, the LED light chip temperature, light-emitting device performance will lead to changes in attenuation and photoelectric conversion efficiency, even when serious failure, the LED lights of the heat dissipation problem is quite critical.

During use, LED will emit heat, so that the die junction temperature rose rapidly. LED effect that the higher the greater the heating effect. According to the experimental tests show that: LED temperature increase of 5 degrees Celsius itself, luminous flux decrease of 3%. Therefore, LED light must pay attention to the work of their own heat. Staff before lighting the most troublesome is the process of exchange take place when light caused by high temperature as lamp lighting staffed accident and burn burn. Even a red when fully opened headlamp lit a cigarette, lighting after shooting as high temperature, lighting equipment can not be immediately finishing packing, must wait for the lamp to cool down before they can, very easily. It is recommended that users try to choose the time of purchase with a temperature indicator and large heat sink of the LED lights.

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