Cinematic Lighting Vs Natural Lighting

INTRODUCTION

You may think that cinematography would be all about using a camera. However, the most important part of a cinematographer’s job is actually lighting. 

Scenes are lit to: create a look that tonally suits the story, to provide a consistent source of illumination that doesn’t change or effect continuity, and to give the camera enough light to be able to properly expose.

In this video I’ll show you two different lighting setups for two different looks and compare how you can get away with using only natural light, or how you can elevate that look a bit more by supplementing natural light in a motivated way. 

MOTIVATED LIGHTING

Lighting can take two forms. It can be more expressionist and exaggerated, to completely elevate the footage out of the real world. Or it can be naturalistic, where, although artificial lights are used, they are used more subtly in a motivated way to keep the story within the bounds of realism.

Today we’ll focus on creating a naturalistic look by using motivated lighting. What exactly is that?

Motivated lighting involves first examining the natural light sources that are present in the space and then placing additional artificial film lights to supplement the natural light.

Or, sometimes, if a source doesn’t exist, cinematographers will create an imaginary motivation for it in their head (outside of the frame of the shot) and then add artificial light using that idea. 

There are three things to consider when lighting in this way: the direction of the light, the quality of the light and the colour of the light.    

Let’s keep these three factors in mind when we go about creating two different looks: a brighter illuminated high key look and a more shadowy low key look.

HIGH KEY - NATURAL 

Let’s start by showing how we can create a high key look - without many shadows on our subject - using only the natural available light.

When only using ambient light in a space, it’s very important to be aware of what the natural light is doing. 

I chose to shoot the natural light look at a specific time in the morning where the sun was still low enough in the sky that it would angle in I through the main window in the space. I checked the forecast beforehand and made sure it was a sunny day. Light scouting, weather observation and scheduling is very important when dealing with only natural light.

Next we need to think about direction. In this room the main source of light comes from a large window on the side and a smaller window from the back. 

Another important part of natural lighting is how you position the subject. Rather than placing her so that she is directly in front of the window and the light source is totally front on and flat, I’ve positioned her so that she is side lit by the sun coming through the window.

Also, placing the main source of light directly behind the camera is normally not a good idea as it may cast the shadow of the camera onto the subject. 

This positioning of the subject means the natural light comes through and creates contrast on one side of the face. Also this little window provides a small backlight which separates her from the background.

Now that direction is sorted we can focus on the quality of the light. I’ve used a muslin curtain to diffuse the intensity of the light, softening any shadows, and reducing the brightness of the illumination outside the window. 

When setting the exposure level for a high key look I’ve focused on the illumination of the skin by increasing exposure - in this case with an ND filter - until I’m happy with the level of light on the face. This may mean that the area by the window blows out a little bit - or turns to pure white - which isn’t ideal but we can’t control that. Not without lights anyway.

Finally, the colour of our light is that of the natural sun - which also can’t be changed. One reason I usually don’t turn on any overhead house lights when using natural light is because mixing the colour of artificial warmer ceiling bulbs and natural daylight may throw off how colour is recorded.

So there we go, a high key look using only natural light.

HIGH KEY - CINEMATIC 

One reason that DPs use lights to still create a naturalistic look is because of this curtain in the background. It’s a bit blown out. In other words the natural light from outside is much too bright and turns to white, lost information. This is not pleasing to the eye.

So to create a better look I will start by setting the exposure of the camera so that it is balanced to the light in the background by only looking at this window. Now it’s not blowing out, however, it’s much too dark to be a high key look. 

So, we need to add light. Let’s start by thinking about direction. 

Our strongest source of light is coming from the window - we’ll call this our key. Then some of that lighting from the window is coming inside and bouncing back as a soft ambient source - we’ll call this our fill. Then, finally, ambient light from that little window is hitting the back of her head - we’ll call that our backlight.

Using three light sources in this way is called three point lighting.

Now that we’ve identified where the light is coming from, let’s add film lights that mimic the direction of the natural sources. 

With our lights on hand, let’s think about the quality of the light that we want. Because the sunlight coming through the big window is strongest we’ll put our biggest light there - a Nanlite Forza 500B II.

The sunlight coming through the window has been diffused by the curtain and is nice and soft, so we’ll do the same and add a softbox, with a layer of stronger diffusion in front of it to soften it as much as possible. I’ve also added an egg crate grid to it which controls the spread of the light, focusing it more directly on our subject and preventing it from spilling everywhere.

Next, we’ll take our second strongest light, a Forza 60B, and use it to recreate some of the natural ambient fill light. This we’ll also diffuse and make nice and soft by using a lantern. This creates more of a soft spread of light. As you can see here it hits the little plant on the table. This mimics the spread and quality of natural ambient sunlight bouncing off a wall. 

Finally I rigged a little tube light on an extended c-stand arm as a backlight. This ever so slightly adds to the feel of the light coming from the back window. 

Now, for our third variable: colour. To me, the brightness of high key lighting feels like it would go well with a warm, morning look, so I cranked all the colour temps on my lights to 5,000 Kelvin - which is just a bit warmer than normal sunlight. 

The 500B also comes with a cool new feature of being able to adjust the amount of magenta or green tint to the light. So I added a bit of magenta which to my eye helps give a warmth to the skin tones.

And there we have it. A high key look - this time with added artificial lighting that should still feel quite natural.

LOW KEY - NATURAL 

Let’s take away those lights and create a new low key look with only natural light. 

Rather than being bright like the high key look, low key lighting accentuates shadows and darker tones and usually has an overall higher contrast between areas of light and shadow.

Since we’re not allowed to use any lights we’ll keep the same positioning, quality and colour of light as before. However, we are going to change our overall exposure. 

To prevent those window highlights from blowing out like they did for the high key look, we’ll lower the exposure using an ND filter on the front of the lens, until we can still read information on the window and it’s not blown out.
This leaves the frame looking much moodier than before, even though the only change made was in exposure, not in lighting.

This creates plenty of shadows across the frame, which may work as a nice look for some stories, however may be a bit too dark for others.

LOW KEY - CINEMATIC 

So, let’s see if we can’t find a middle ground between the very shadowy low key, natural light look and the high key look - by introducing some film lights.

We’ll use almost the same placement for our key light as before. But this time, instead of being more in front of the character, we’ll bring it around a little bit more until it’s right on the edge of the frame and is lighting more from the side. 

This will create just a little bit more contrast, as less light will fall on the side of her face nearest to the camera.

We’ll go ahead and turn on the same backlight as before. However, this time, we’ll leave our fill light off. 

If you compare the high key lighting shot that uses a fill light and the low key shot without one you’ll see that not illuminating the one side of her face creates a gentle shadow on the side that favours the camera - therefore creating more contrast.

Because I’ve moved the key light around, there is less light that spills on the wall behind her, which also makes it feel like more of a low key look.

On top of this, there is a slight difference in colour. Because the low key look is a bit moodier, I cooled down the colour temperature on my fixtures from 5,000K to 6,000K.

So there we go. A low key look that was achieved with motivated lighting, by simply eliminating the fill.      

ADVANTAGES OF USING ARTIFICIAL LIGHT

Four different looks: two created without any lights and two created using artificial sources. Lighting is always subjective and should change depending on the nature of the story you are telling. 

This look may be better suited for commercial applications, while this look works for a film with more dramatic content.

But besides the look, what other advantages does using lights provide? Perhaps most importantly using lights creates a consistent look, which will hold up for much longer periods of shooting. 

If it takes a couple of hours to shoot a scene using only natural light, the look of the ambience may have completely shifted as clouds came over, or the sun got flagged by a building. This means that the consistency and continuity when cutting to different shots will be off.

Using film lights means that even if the natural light changes, the artificial light should maintain the continuity of the look, which means you will be able to shoot for longer.

Also, relying purely on natural light means you have limited to no control over the look of the image. For this video I could pick a day and a specific time where I knew we would get strong sunlight, but that isn’t always the case. If you need an interior to look warm and sunny, but it rains that day and you don’t have any lights, then there’s not much you can do.