- Let there be light.
- Cinematography is often described as painting with light.
The primary tool in this process is the light meter,
which to this day, helps filmmakers create stunning images.
This is 'What is a Light Meter'.
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Now, entering light speed.
- You ready, Hecrum?
- Alright, should we do this?
- A light meter is a device that measures quantities of light
either in footcandles or lux.
Light meters that calculate camera settings based on these measurements
are also referred to as exposure meters.
Exposure is controlled using three elements.
ISO, shutter speed, and aperture.
Once a photographer or cinematographer knows the amount of light, they
can adjust these elements to obtain the desired exposure.
For a deep dive into exposure triangle, a playlist of the videos and our free
ebook are linked in the description.
Now that we understand what they do, let's look at the
different types of light meters.
The most common variations of meters fall into two categories,
incident and reflective.
Incident meters measure the amount of light hitting an object.
They can be identified by the white sphere near the top of
the device called a lumisphere.
The sphere allows the equipment to take a reading of the light hitting
the subject from all 180 degrees
mimicking the spherical shape of a face.
Reflective light meters, also referred to as spot meters, measure the amount of
light being reflected off of an object.
Spot meters are typically used for more specific readings of smaller areas.
Rather than measure the amount of light hitting the entirety of a
subject, they may be used to measure highlights and shadows independently.
Reflective light meters usually work best when measuring a mid-tone or middle gray card,
a color that refers to the exact halfway point between white and black.
Some cameras have light meters built into them, and these are also usually
reflective with different metering modes.
Light meters can either be analog or digital.
Analog meters display results with a needle.
Digital meters use an LED screen.
While analog meters are typically cheaper, they also are sometimes less accurate.
For filmmakers looking to save money, there are light meter apps
for smartphones that use a phone's camera to measure light levels.
But these too are often less accurate.
There are also light meters which include readings on the intensity
of different light wavelengths.
These tools are called spectroradiometers, or spectrometers, and give filmmakers a
detailed idea of the different colors and qualities of light present in a scene.
Because these devices include such intricate measurements, they
are usually much more expensive than common light meters.
No matter what type of meter you're using, you'll want to
ensure they have a cine option.
Light meters for photography will have different reading settings,
typically calculating shutter speed rather than aperture.
There are other ways to ensure an image is exposed correctly.
Some monitors have false color features, which use different colors to indicate
different levels of exposure in a shot.
Monitors may also have a zebra setting, which adds stripes to anything
in the frame that is overexposed.
Filmmakers may also utilize histograms, graphs that show the prominence
of different exposure levels.
But meters can bring a level of precision and tactility that
readings on a monitor cannot.
Let's look at why filmmakers use light meters.
In an era where digital cameras have a wider dynamic range than ever, and
post-production coloring can transform images, it's easy to see why some think
light meters are becoming obsolete.
But even today, they can be vital tools on set.
First and foremost, light meters allow you to get a more detailed
understanding of the light in a scene.
Monitors, and even the naked eye, can be deceiving.
Meters can decisively tell you what is properly exposed in your frame.
They also allow a cinematographer to communicate
with their gaffers and grips more effectively.
Rather than speaking in vague terms like lighter and darker
a DP can give their team specific values to hit in certain locations.
Meters allow for light setups to begin before a camera has even arrived.
With a meter handy, gaffers and grips can rig a scene without having to
check how the light looks on camera.
This is particularly useful for tech scouts as well.
A crew can measure the pre-existing ambient light in a given location
to better understand how to approach lighting on the shoot day.
A light meter can also ensure exposure continuity for shots where the
camera moves through space, like a long tracking shot for example.
- What's a foot massage?
- A foot massage is nothing.
I gave my mother a foot massage.
- The meter can take measurements throughout the camera's path to make sure the
frame will remain adequately lit.
Similarly, meters can maintain lighting consistency from shot to shot.
- But what if I need you?
- A DP will typically use the device to measure the contrast ratio in a shot
which refers to the difference in intensity between the key light
and fill light on a subject.
Typically 2:1, 4:1, or 8:1.
Some meters will have save readings, allowing for contrast ratios
to be calculated more easily.
A DP will often aim to keep this ratio throughout a given scene.
This is especially useful if a scene is outside where the sun is moving throughout
the day, or if reshoots are necessary and a DP has to match lighting from a
shot taken days or even weeks before.
Light meters can also be helpful when conducting camera tests.
Some cinematographers will measure shadows and highlights with a
meter and then color the footage.
This allows them to better understand the dynamic range they
are working with on a given camera.
More rigorous camera testing using a meter can help a cinematographer determine
the true ASA of a camera, which is often slightly different than they are labeled.
Of course, a light meter is only useful if you know how to use it.
Using a meter is relatively straightforward, but there are
a few factors to keep in mind.
First, set the device to the same ISO as your camera.
If you're shooting on film, match the ISO to the roll of film.
Next, match your shutter speed and shutter angle to the same as your camera.
For most projects, this angle should be 180 degrees.
For wide shots of landscapes, you can hold your meter in front of the camera,
averaging light in the general setting.
If you are using an incident light meter, make sure the
lumisphere is facing the camera.
If your subject is flat, you can flatten the sphere, depending on the device.
If you are using a reflective meter, face the device towards the
subject rather than at the camera.
You should face the subject from the same direction as your camera.
Finally, press the button on the side of the meter.
The tool will then indicate the f-stop for normal exposure.
From here, you can decide to over or underexpose.
When shooting on film, it's usually best practice to expose for the
shadows, since film can handle overexposure better than underexposure.
For scenes with high contrast, getting multiple readings in different
areas of a frame is a good idea.
This will give you better understanding of what will be under and overexposed.
For heavily backlit scenes, you may be able to get a reading of the light source.
Since it's facing towards the camera, but is obstructed by the subject.
Finally, it is always a good idea to consider reflectance.
Black material will reflect light less than white material, and vice versa.
This is where a spot meter can be useful.
Light meters have a multitude of uses.
Using one of these small but mighty devices can allow you to light
more confidently, and makes a colorist's job easier down the line.
Great cinematography relies on great lighting and lots of preparation.
Start planning out your shots with StudioBinder's storyboard software.
Goodbye for now.
Shine brightly, but not too bright.