Shooting with the natural light coming through windows is not as easy as it looks.
Filmmakers working with a low shooting budget might think that they can cut a few corners using nature's best and cheapest lighting tool, sunlight coming through windows, but doing this can yield messy results if you're not keeping track of your indoor and outdoor exposures.
You might light your interior perfectly, but end up with blown-out (or "hot" white pockets of light) in your view of the exterior, because it's being overexposed.
One option is to wait for golden hour each day, which usually offers optimal lighting, although only for a few minutes. What if you need to shoot for longer periods and at different times of the day?
PremiumBeat has put together these great tips for using windows as natural light sources for daytime interior shots.
1. Use neutral density gel sheets
ND gel sheets are usually sold in rolls and can be either affixed to the windows in your shot or hung on C-stands. This will lower the intensity of the light coming through the windows from outside and will balance the exposure.
Another option would be to put ND filters directly over the camera lens to even out all the lighting in your shot.
2. Allow the exterior lighting to be blown out
When this is done purposefully, it can help focus your scene on the interior action and look professional.
This is accomplished by hanging a fabric like grid cloth at the window, instead of ND, which blows out the entire exterior and creates an even white light.
If you're shooting a period film and you have an exterior view that doesn't match the period of your interior, this is a great option for maintaining your setting. If you've seen 2012's Lincoln, you may have noticed this technique being used.
You can also add exterior lighting through the grid cloth if you desire, which gives the scene a kind of heavenly look and would allow you to shoot both day and night.
3. Add interior lighting to balance the exposures
A third and probably least attractive option would be to add lighting inside, matching the interior and exterior exposure levels.
However, this requires buying additional lighting, which you might not have the money for. It also doesn't look as natural and cinematic as the other lighting methods. And finally, actors might not appreciate having light blasted into their faces.
What's next? Check out some more of No Film School's lighting resources.
Learn more about bouncing natural light in your scenes, or how DP Rachel Morrison achieved a natural lighting look for Mudbound. And here are some tips for faking natural lighting effects like fire or the moon.