What Is Light?:
Basic Information for the Photographer and Videographer


What Is Light

What is light? Well… It's the most basic thing a videographer or photographer works with! Knowing a little something about it will make it easy for you to shoot like a Pro! Let's take a look at some of the fundamentals of this peculiar type of energy!


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If you are a photographer or videographer you've heard all the terms connected with the creation of a digital image:

What is light – Lightning Strike
  • Pixels,
  • Resolution,
  • Primary and Secondary Colors,
  • Brightness (Intensity),
  • Luminance,
  • Chrominance,
  • White Balance,
  • Gamma... etc. etc.

When you talk about any of them… You're talking about Light!

Light! What the human eye detects. It is, of course, only because of light that we can see!

What is light?  Modern photography and videography depend on creating an image from this peculiar type of energy that we can perceive so well with our eyes.… So… What is it?

To understand light we have to go into some of the simple basics of physics...

We have to explore what photons, electromagnetic radiation and what waves are to really understand the fundamentals of how digital images are made and how we can control light to get the type of shots that we want.

What Is Light?... A Simple Definition of Light...

A simple definition of what Light is:

Definition of Light

"Light is a type of energy. It's a form of electromagnetic radiation that is of a wavelength which can be detected by the human eye. It is a small part of the electromagnetic spectrum. Animals can also see light. Light exists in tiny particles called photons." (Simple English Wikipedia)

Okay… I believe in breaking things down into simplicities... so let's delve deeper into the terms used in this definition so that we can get an even clearer understanding of what light is so that we can better answer the question... What is Light?

What Is Light? ... The Component Parts of Light...

Waves:

Mechanical Waves

A wave is a surge or progressive movement. There are two types of waves: Mechanical and Electromagnetic.

Mechanical waves need a medium to propagate... such as air or water. The key to mechanical waves is the movement of molecules.

Light is propagated as a electromagnetic wave.

This type of wave does not need air or solid materials to move in… can also move through the vacuum of space.


Electromagnetic Wave:

Electromagnetic Wave

When an electrical field and a magnetic field are coupled together...

The two fields vibrate and a wave is formed and propagated.

This is called an electromagnetic wave.

The length of the wave determines its position on the electromagnetic spectrum.


Photon:

Photons

A particle of energy with wave-like properties.

It's the only type of energy that is a "thing". Photons travel at the speed of light (unless otherwise interacted upon), they have no mass but... They do have momentum.

Light is made up of these units of energy and is part of the electromagnetic spectrum.


Energy:

Types of Energy

Most people think of energy as: What we need to accomplish physical actions.

But that definition would be more like what energy is used for and not what it is.

A more precise definition of energy would be the potential capability of an object or system to do work or exert influence on another object or system. "Potential" because energy can be conserved.

The physics definition of work applies here: Work = Force x Distance.

Energy breaks down into nine different forms: 1. Sound Energy. 2. Nuclear Energy. 3. Kinetic Energy. 4. Potential Energy. 5. Thermal (Heat) Energy. 6. Chemical Energy. 7. Electrical Energy. 8. Electrochemical Energy. 9. Light (Electromagnetic Energy).


Electromagnetic Spectrum:

Electromagnetic energy spans a broad spectrum. 

It is energy in the form of electromagnetic waves and can be broken down by the length (frequency) of the wave from the longest to the shortest.

Electromagnetic Spectrum

They are:

  • Radio Waves,
  • Microwaves,
  • Infrared Waves,
  • Near-Infrared Waves,
  • Visible Light,
  • Ultraviolet Waves,
  • X-Rays, and the shortest which are...
  • Gamma Rays.

Visible Light:

The part of the electromagnetic spectrum that we can perceive with our eyes. It has characteristics such as; Color, Direction and Intensity.

How Does This Pertain to You...? The Photographer or Videographer...

NASA Electromagnetic Spectrum Tour

If you want a deeper dive into what the Electromagnetic Spectrum is...

NASA has a great website that will help you do this!

Click here for a Tour of the Electromagnetic Spectrum

Enjoy!


All of those terms I mentioned in the first part of this article…

All stem from this basic and fundamental information of what is Light.

It is one of the most important subjects to learn if you're going to be a great photographer or videographer.

You have to master the use and control of light to be able to manipulate it in a way that you get exactly the image that you want when you're shooting a subject or scene.

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So... know the basics of what light is and how to control it, manipulate it, compensate for it, and how to use it to enhance an important element in the shot...

That way you will always be able to capture a great image of what you're shooting... Every time!


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Have fun...!  Dan


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