Lighting is so important in ensuring a quality picture in videos. On film sets, there is an entire department dedicated to designing a light setup and they work under the direction of the Gaffer, who works under the direction of the Director of Photography.
In smaller productions (documentaries & videography) you have to be a bit creative and use whatever light is available. Smaller light sets can be used but depending on what you are doing and where you are, they may not be logical (i.e. shooting out in the woods). Generators can be used but the more equipment you have the more crew you need to lug it around and set it up so there are other ways around it if you don’t have the money to pay for the extra crew members for your video production.
Reflectors are great. These are just two sided pieces of fabric stretched out over a flexible oval/board frame. They are great because they compact, lightweight and cheap. Reflectors don’t have a huge amount of power and they need light to reflect so they are great for just filling in shadows on faces or lighting up details that can be lost when the lighting is too low.
Clip on LED lights. I like these sometimes. Rarely though. I have them but I don’t tend to use them much. The reason being is that they are like a giant flashlight accouncing what the video camera is shooting. I tend to capture a lot of candid video so I don’t like when people know I am shooting them because they will act differently and having a light in their face takes them out of the moment. I understand this and I myself do not enjoy being in-front of the camera, trust me. They are also like a spotlight, so everything around the subject is dark but the subject is well lit. This can be a nice effect if that is what you are looking for but for me I generally avoid it.
Interior lights in houses. These are not usually very flattering. Tungsten lights are usually fairly yellow and come from above or from the side on a lamp so they are low light and can sometimes cast shadows on faces. If you want a dramatic yellow shadowy face then great, but other than that I am not really super fond of them. Fluorescents look green on a video camera so if you are in a room with both tungsten and fluorescent lights then you will have to be creative. I usually adjust my white balance accordingly and then find one that has a good distribution and shoot around it. Sometimes I will turn certain lights off if they are contrasting other lights in my shot.
Natural light. This is the bees knees. While natural light can be a bit problematic (clouds going over the sun) you can use it to your advantage to create a clear image in your video with the right amount of shadow and light. I love the way it shows up on camera without adding anything extra that needs to be removed in post production. Playing around with different angles of natural light is fun too. Typically people are told to shoot with the light on their backs to it lights up their subjects but if you actually do the opposite you can have a really night lit background with some fun lens flares shooting through. My cinematography teacher in Prague didn’t like that look too much but I personally love it. Natural light changes with the day so it’s always a good idea to know when and where the sun rises and falls so you can work with it instead of fighting it.
There are of course many many more types of lights to use in your video so explore and experiment and see what happens, that’s the best way to learn!
Take a look at this video by Nacho Guzman on how different colors and light angles change this woman’s face: