Tips for Using LED Continuous Lights for Video
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Hi folks. This article I want to spend some time on continuous lights, particularly in the context of video, but there are (limited) applications for LED type continuous lights for still photography as well. Specifically for things that do not move where you can use long shutter speeds. Otherwise, mostly useless for stills.
By continuous light, we mean a light that has an off/on switch that stays lit while power is provided. Ostensibly the device puts out continuous light so long as there is power. That light should have consistent colour temperature and luminosity but may not depending on the engineering.
We are long past the days of incandescent, halogen, mercury, sodium and other halide based lighting which used a lot of power to produce a level of luminance with enormous amounts of the power applied being dissipated as heat. Fluorescents used less power, and produced less heat for similar levels of luminance but have serious colour shift and flickering issues. Except in the really high end fluorescents, it was an idea that did not last all that well.
Bring On the LED Lights
Today we have LED based lights, and as happens somewhat regularly, as time has passed, more options exist and prices have dropped. The professional grade LEDs have not gotten less expensive, but more companies have entered the space with options.
An LED or Light Emitting Diode is not a new idea. LEDs are very power efficient with minimal energy loss to heat. However, like fluorescent lights, LEDs flicker and the better lights use timing electronics to try to have the LEDs go through their flicker cycles at different intervals. Diodes, are fundamentally switches and at a very simplistic level that’s why they flicker. Once could get very particular and say that then they are not continuous and be factually correct, but that is for elsewhere on the interwebs. So long as we understand and accept that LEDs flicker we can move on.
The brightness of an LED is fixed. It generates luminance as a function of voltage. Some LEDs are only ever on or off. Some LEDs can produce illumination of different levels by varying the power to them. Some LEDs are more complex diodes that can vary their colour temperature based on an electronic instruction. In this regard, they are very powerful little lights. As always, what sounds like a great idea might be, or might open a bag of trouble.
Lighting on Set
The term “on set” means a shooting location where the environment is very well controlled and indoors. You have control over the temperature, the weather and access and you also have control over the light and the power sources for the light.
In this scenario LED panels make a great deal of sense. They put out a reasonable amount of light relative to their size, and are relatively inexpensive. Some run on batteries and most will run off AC, which in a studio is to my mind preferable as I don’t want voltage changes to change the light during a series of shots. I would buy the largest panels possible and where it makes sense, gang them together into a single larger panel, the larger the source, the softer the light as you know. Scrimming LEDs cuts the amount of light on subject which will necessitate an increase in gain. Variable power is nice, but in all my years of doing video, I have very rarely turned a light down in output, instead using gain, or ND filters to get where I need to go. I have seen colour temperature shifts when the output is changed and I do not have the money for high end KinoFlo LED panels that don’t do this.
I don’t care about variable colour temperature. Just a light that gives me accurate and consistent 5600K is all I need. If I need a different colour temperature, I will use a Rosco or Lee colour specific gel and some gaffer tape. That’s my choice, but some experimenting proved enough that variable colour temp delivers inconsistency and that if you do not have a colour meter on set you’re potentially in trouble
On The Go
In an on the go shooting situation, the lowest denominator is an on camera LED panel. These are light and convenient until you put a battery of decent capacity on the back and then you have a top heavy wobble box. They also tend to have a limited number of LEDs and produce very hard light due to small size. The illusion that a diffusion filter softens the light is, as we all know by now, a load of poop. If the source does not get bigger, the light does not get softer. Period. Because they are so underpowered, using that diffusion panel is going to cost you light on subject and that means a gain change will be needed. While I like the idea of the little Lume Cubes, in practical terms for video, they are pretty useless unless you get them really close, or are videoing a very small subject with the light pretty much on top of it. Far better to put a large panel with a big battery on a light stand and work from there. We’ve talked about using gain to compensate for poor light overall, so your use of an LED panel is mostly to fill shadows and fix annoying colour shifts.
Unless you have a colour meter, matching LEDs to existing light is near impossible and if you will do it, your box of gels is typically a better option, or make the LED the dominant source through the use of gain and ND filters.
Buying LED Panels
Do I get more buying an Arri or KinoFlo panel? Yes you absolutely do. However if you are not getting paid for your videos in large chunks renting for those occasions or going with less expensive offshore built panels may make more sense. There is a line between less expensive and junk, and sadly this line is rather hard to find. Before Bowens went under, they had a line of really fine LED panels that were really tough, and really accurate from a colour temperature perspective, but they are gone so that’s out. In that kind of range, I have had success with Lowel and LEDGO panels. I like the Rotolight stuff but it’s underpowered for the price. At the less pricey level, I have a lot of experience with varying brands or labels, and the only one that I would recommend is the Godox line. They cost about the same or less than other very similar offshore made lights and they are not pro grade durable, but they are consistent and you can get a decent level of output from them.
The most important thing to look for, after 5600K colour temperature in an LED light is output wattage. LUX and other metrics are so widely misconstrued as to be an exercise in detective work just to find out the truth. More watts is better. Always. Any other features such as adjustable output or adjustable colour temperature are might be benefits, but personally I don’t use them and so don’t look for anything other than colour temp and as much power as I can find for the dollar spent.
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I'm Ross Chevalier, thanks for reading, watching and listening and until next time, peace.
