The Inverse Square Law

The inverse square law is the intensity of light from a constant source falls off as the square of the distance from the source. Any light source that spreads light in all directions, i.e. a lightbulb obeys this law. If you were to walk away from a campfire in the middle of a dark woods, it would get dark pretty quickly. Basically, the double the distance you are from the light, you quarter the light intensity. The light falls off 1 over the distance multiplied by itself. The light measured at 2 metres from the source will be half squared the intensity, if it was one meter it would be a quarter of the intensity. a light measured 4 metres from the same source would be a quarter squared or a sixteenth the intensity at one metre. In photography, as every stop means halving or doubling the light, a quarter of the light is two stops down and a 16th of the light is four stops down. A light reading of f/16 at 1 metre, for example would be f/8 at 2 metres and f/4 at 4 metres. The only light source that conflicts with this law is the sun, as the distance we move something on earth is quite trivial in comparison to the distance between the earth to the sun.

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What is Light?

Light is a gift in some photographic moments, and when light is presented, you must make the best of what you have. However, in the studio, you have full control of the light. I am researching the simple rules and guidelines to improvise my lighting skills and have a better understanding of the aesthetics I can achieve in the studio. I would rather learn from my mistakes, learn from lectures or even books and the internet than have poor quality lighting and ruining my images. Before taking my images or even brainstorming ideas, I feel that I need to understand lighting and build a relationship with it. Understanding the simplest of qualities, will help me understand how to bring out shadows, highlights, detail and saturation. I have chosen three books and various websites to give me the tools to develop my studio skills. As I am aware of photographic lighting, I have no real experience, though I have worked with lighting in moving image. This kind of lighting however, is different.

What is lighting?

Scientifically, light is a narrow band of electromagnetic radiation, we can see it because the optic nerves are sensitive to these bands of radiation. There are no accurate boundaries to the range in which we can see light as individuals are different, but on average our eyes are receptive to a range of wavelengths between 400 – 700 nanometers.

Radient energy exists above and below the visible spectrum of light. Above the visible spectrum is ultraviolet and below is infrared. The digital revolution has allowed us to use technology such as photography and film, to pick up these colours and and convert them into a range of visibility.

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The Electromagnetic Spectrum

Photographers are typically interested in three physical properties of lighting – The wavelength/Frequency, the amplitude/intensity and the angle of vibration/polarization. The intensity of the light determines the brightness, the wavelength determines the colour and the changes of polarization are barely visible to the human eye, however these can be manipulated using polarizing filters.

Light causes shadows because it travels in straight lines, it is then reflected off a shiny surface like a mirror that reverses the angle of which the light falls. These simple laws allow the photographer to manipulate light to their advantage, using reflectors, mirrors and cutters. Light can also be refracted, meaning lenses can be designed to focus an image.

Light allows us to see colour, without it, the world would be colourless. For example, a green pepper only looks green if the corresponding wavelengths are present in the illuminating light. If an orange light that contains no green, falls over a green pepper, the pepper would appear grey and colourless.

Light that contains all the colors of the spectrum is known as daylight, but photographers use this term precisely. White light comes from radiating sources, the sun, lightbulbs, flash guns etc. However there is some underlining connection with heat. Photographers use the theory of colour temperature, the theory wavelengths on the spectrum heating up to describe the exact colour of a lightsorce (tungsten, florescent etc.)

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The Nomograph

Objects – An Introduction to Lights

Today we had the opportunity to play with some of the lighting kit after a demonstration of how to set them up. We had a brief introduction as to what lights are used for what and the extensions that go with them; soft box etc.

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This handout is incredibly useful, it lists the external components and their functions on various Bowens lights. (GM400, Esprit, Esprit 125) It also explains the components and functions of a general light stand.

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This is a photo of the light I set up and the soft box I had attached.

Objects – Assignment Introduction

For our very first assignment in our Objects module, we have to photograph eight objects. The assignment brief states that we must photograph and print one image for each of these eight objects, edit them and analyze them individually. I may take it one step further and compare a few that are similar. I feel that in doing so, I will improve my observation and analytical skills. The objects we must photograph are as follows;

  • A glass Tumbler of milk
  • A Motorcycle, a motor scooter or a horse.
  • A pushbike
  • An egg
  • A fish
  • A loaf of artisan bread
  • A violin
  • A paperclip

We also have to use a large format camera, work with a classmate and shoot in natural light for at least one of those images. We also have a writing task. We must find three still life photographs from each of these photographers;

  • Josef Sudek
  • John Blakemore
  • Richard Caldicott
  • Jan Groover
  • Robert Mapplethorpe
  • Irving Penn
  • Paulette Tavormina
  • Paul Kenny

We must then analyse all 24 images, describing the composition, the lighting and the image quality in high detail.