When the Lighting Gets Tough…
This week, let’s look at some slightly challenging lighting situations: green screen, low-light/night shots, and the great outdoors.
Want a quick way to make your footage look better? Shoot it outside! There is a ton of light outdoors and digital cameras love light. The ambient light you get outside will help your image quality, but it can also make shaping and controlling the light more difficult. Here are the tools and techniques you should be using.
- Reflectors and Bounces – A reflector is your best friend outdoors. If you’re having a hard time with shadows or shade, bring a reflector close to your talent to help illuminate them. A white reflector or bounce will provide the softest light; silver and gold will reflect more, but the quality of light isn’t as pleasing. If you can’t tell whether or not you have a reflector aimed correctly, ask your talent if they can see the reflected light. If you don’t have an actual reflector with you, any flat white surface can be used as a bounce.
- Diffusion and Shade – One of the most challenging aspects of outdoor filming is having too much light. It can be difficult to get correct exposure and you may have harsh shadows depending on the cloud cover and the position of the sun. In those cases, try blocking some of the light using a white reflector or diffusion. If that’s not enough, you can use a black flag – or move your subject to a shady area.
- Battery Power – Just because you’re outside, it doesn’t mean you can’t use lights. You may need to get the lights quite close to your subject to make any significant impact. If you don’t have access to electrical outlets, your best bet is probably battery-powered LED panels.
- Location, Weather, and Time – Because you can’t control the position of the sun, you need to be mindful of where and when you are shooting. If the sun is behind your subject, you may need lots of front lighting to avoid them being silhouetted. Filming when the sun is high in the sky – late morning to early afternoon – can result in unflattering “raccoon eye” shadows on your talent. The sunrise and sunset “golden hours” give beautiful light, but that light also changes and disappears very quickly, so organization is a must. Overcast days are ideal for filming, because the light is diffuse and easy to work with, no matter the angle.
- Exposure Tools and Filters – If you are outdoors in daylight, you can probably keep your ISO as low as it will go; there usually isn’t any need for additional gain. If your image is still over-exposed, you can close your aperture, but then your depth-of-field will get deeper. To maintain a shallow depth-of-field, you can use ND filters – some cameras (such as the FS5 and AF100) have them built-in; otherwise, you can use screw-in filters on the lens or drop-in filters with a matte box.
Lighting at night – or lighting for a nighttime look – poses the opposite problem from shooting outdoors in daylight. Virtually all digital cameras struggle in low light, so night shoots require an extra level of planning.
- ISO, Shutter, and Aperture – If most of your image is going to be dark, your camera may warn you that things are under-exposed. That’s okay, embrace the darkness! Exposure tools and automatic settings assume that you are looking for a well-lit shot and will try to raise your ISO, open your aperture, or lower your shutter speed. Keep your ISO low – grain and noise show up in the dark parts of an image first, so you want to protect those. Opening the aperture instead is a good idea, as long as you don’t mind a shallower depth-of-field. You can lower your shutter speed a bit if you are desperate, but don’t overdo it. Your best option is to bring more light into the scene.
- Back and Side Lighting – Single-source lighting is one way to get that nighttime look. Remember that the light should be motivated – is it coming from the moon, car headlights, a computer screen? This is especially important for night shoots, since “unmotivated” lights will stand out. Lighting your subject primarily from the back or side is another way to get a usable image while maintaining a style that reads “night.” Finally, consider lighting the background of a shot and letting your subjects fall into silhouette – this can be a cool effect.
- Using Color – We tend to associate warm orange and yellow light with sunny days and cool blue tones with night. Use this to your advantage and light your scene using a blue color palette to simulate a nighttime look.
- Believability Versus Realism – Moonlight isn’t really blue and you probably wouldn’t really be edge-lit in a dark and spooky forest. That’s fine. Instead of trying to realistically recreate a dark scene, think about what might believably represent a dark scene.
Green Screen Lighting
The key to good green screen compositing isn’t the post-production process you use – it’s the prep you do on set. Lighting and exposing your green screen effectively will save you countless headaches later.
- Screen Prepping – Your green screen should be as smooth as possible, with no obvious wrinkles or folds. If you are using a fabric screen, you may want to use a portable steamer to smooth it out. You can also use weights to pull it taut.
- Screen Lighting – Use soft, even lighting and make sure that the light is cast equally over the entire screen. You want to avoid having some parts of the screen lighter or darker than others. In the studio, we have special green fluorescent lights that we can use to help even things out.
- Camera Exposure – If you have access to an RGB waveform, set your exposure so that the green channel is hitting around the 40-50% mark. Pushing it higher (brighter) can introduce other colors into the spectrum, which will make keying more difficult. You may also want to shoot with a wide aperture so that the green screen falls out of focus a bit – this will help smooth out any small wrinkles or imperfections.
- Backlighting and Spill – If your subject is too close to the green screen, it will reflect green light onto them. Get your subject as far from the green screen as possible and use a longer lens to compress the distance. Back-lighting is also extremely important for green screen work, since you want to separate the subject from the background. You may want to try using two backlights, one on each side.
- Key and Fill – If at all possible, you should have a good idea of the lighting you will be trying to match when you film against a green screen. Will the final composited scene be high key or low key? Outdoors or indoors? Match that lighting on your subject as closely as you can. You may also want to light your green screen using daylight-balanced lighting and your subject using tungsten – this will help create separation between them and the backdrop.
- Green Screener – I haven’t tried it yet, but there is an app called Green Screener that uses your phone’s camera to check the quality of a green screen setup. You can get it at both the iTunes App Store and the Google Play Store.