The key ingredient to photography? The light.

The word "photography" derives from the composition of 2 words in Greek: photo (phos) and graphy (graphis), therefore literally "photography" means drawing with light. The latter is therefore the essential element to be able to take an image, without it we could not speak of photography. But what is light?

The term light (from the Latin lux ) refers to the portion of the electromagnetic spectrum visible to the human eye. This portion is very limited and is between the wavelengths of approximately 400 and 780 nanometers.

The fact that we humans can perceive only such a limited part of electromagnetic radiation in the form of light is due to the particular nature of our eyes. When the eye receives a radiation whose wavelength is, for example, 470 nanometers we see blue light while with a radiation of 650 nanometers we see red.

Color perception is due to the fact that objects retain some light frequencies and reflect others. They are the latter to determine its color.

The various colors visible to the human eye are clearly distinguishable in the rainbow and are indicated below with the relative wavelengths:

Violet 410 nm

Blue 470nm

Green 520nm

Yellow 580nm

Orange 600 nm

Red 650nm

If we add up all the various wavelengths (ie all the colors visible to us) we get a white light .

In 1666, Isaac Newton scientifically demonstrated that by passing a ray of white light through a crystal prism, it is deflected, giving rise to a succession of colored light rays (corresponding to the different electromagnetic frequencies).

Types of light

One of the first things to evaluate before taking a picture is the type of light we are facing: natural light or artificial light.

1 - Natural light

Natural light is that which comes from the sun. It is the most sought after in photography even if it is not always easy to manage. It changes rapidly in colour, intensity and direction and it is therefore essential to get to know it quickly to enhance the characteristics and atmosphere of the subject we are photographing.

In the absence of clouds, the best times to photograph are in the early morning or late afternoon when the light is softer and comes from a side angle. Soft light allows us to collect more details, it is warmer in color and therefore more pleasant for us. Furthermore, the shadows are long and allow us to give three-dimensionality to the subject we are photographing. The only precaution is to position our subject (in the case of a portrait) so that the light does not come only from one side in order to avoid half of the face finding itself in the shadow.

The worst time to photograph, always in case of full sun without clouds, is midday. The light is very hard and consequently also the contrast. The shadows are very sharp and the lights very strong. It is therefore very difficult to find the right setting to take a photo, there is always the risk of burning the highlights or closing the shadows too much, furthermore direct light flattens everything and does not give three-dimensionality to the objects around us. So try to avoid the central hours of the day.

My personal favorite time of day is what photographers call the “blue hour”. Immediately after sunset, before the light disappears completely, there is a short period of time in which the little light present takes on shades ranging from dark blue to violet. You need a tripod to take pictures as the light is very low and you risk camera shake. Furthermore, particular effects can be created (with water or moving clouds) by lengthening the exposure times without having to resort to particular ND filters used during the day in full light.

2 - Artificial light

Artificial light is light that comes from a light source other than the sun and can be divided into many sub-categories: tungsten, incandescent, fluorescent, halogen, LED, laser, flash. The latter, unlike all the others, has the same color temperature as daylight and is among the most used in photography.

While I prefer never to use flash and artificial lights, this type of lighting still has several advantages, one of which is total control over the lighting. Not only will you be able to shoot at any time of the day and in any place but you will also be able to decide the power of the light, the direction and any color, something that cannot be done with the sun. Plus, when exposure times are too long, flash lets you freeze the action for a sharply focused photo.

The 4 basic concepts of light in photography

Knowing that you need light to take photography is nothing overwhelming or innovative, it's a well-known thing. If you're a photographer who wants to become aware of what he's doing, then memorize these four basic concepts

1. The intensity of the light

The first thing you have to do when you enter an environment that you have to photograph is to evaluate the intensity of the light . Whether natural or artificial.

The intensity of light can also be identified as a quantity, in the end it is just a matter of understanding how much is present .

Leave the camera aside for a moment and imagine how your eyes react to changes in brightness:

• if you go from a light room to a dark one for a while you won't see anything… everything is dark. In this case you find yourself in a situation of “ underexposure ”.
• if you go from a dark room to a light one for a while you will be dazzled by the brightness. As long as your eyes don't get used to it, you are in an " overexposure " situation.

You will have to behave in the same way with the camera : if the scene has an enormous amount of light you will have to set a suitable combination of ISO — TIME and APERTURE aperture. If you shoot in Shutter Priority mode, you just need to specifically adjust the chosen shutter speed and ISO sensitivity : the aperture will be adjusted automatically by the camera.

Obviously in this case you must be aware that you cannot use a shutter speed that is too slow , because the excessive amount of light would make it impossible for the camera to set an adequate aperture and you would risk finding yourself an overexposed photo.

The same is true if you shoot in Aperture Priority ; in this case you have to be careful not to use an excessively open aperture which would put the camera in difficulty, which may not be able to use a sufficiently fast shutter speed.

The same principle applies to the opposite situation: with a low amount of light. You'll have to pay attention to the most suitable settings, but with the advantage of possibly being able to increase the ISO sensitivity to make the camera more sensitive to light.

2. The quality of light

The quality of light is not something we can measure . It has to do with visual perception and therefore we talk about:

• Hard Light
  
• Soft (soft) light

Harsh light is usually easy to spot because it's the one that " bothers ": as we said above, that intense light typical of the summer noon on a clear day to understand. Hard light creates very dark and defined shadows of objects. Consequently it also creates strong contrasts between the dark areas and the light areas of the photographed scene.

Soft (or soft) light is the opposite. It is the typical lighting situation of a cloudy day, with the sun behind the clouds that fails to illuminate the scene violently and consequently the objects present soft shadows, often not very evident without creating great contrasts between the shaded areas and those exposed directly to light.

For this very reason we speak of " soft light " or " soft light ".

If we consider sunlight , it is the presence of clouds that differentiates a scene lit by hard light from one with soft light .

Ok, you can possibly take advantage of opaque panels (also called diffusers) to break the hardness of the light if you have to photograph small objects, but how do you do it in case of artificial light?

Add a diffuser to get a “soft” light
Photographers, by and large, much prefer soft (subdued) light as it is suitable for most photographic contexts — from landscapes to portraits — but that doesn't mean you can't use hard light to create some “dramatic” effect. ” (i.e. with strong contrasts).

3. The temperature of the light  

When we talk about the temperature of light we refer to its color .

The photo you see above is obviously tending towards “blue”. Below the correct dominant.

Light does not always have the same color and the most striking example is the fiery red tint it takes on during beautiful summer sunsets or at sunrise.

In reality, however, the light varies continuously during the day with the variations given by the presence of cloudy skies, fog or other particular atmospheric conditions.

The color temperature (or color) of light has a profound impact on digital photography , so you'll need to remember to properly adjust the white balance on your camera.

With the same white balance adjustment tool you can also intervene to modify the visual aspect of the image you are photographing: if, for example, during a sunlit scene you set the shade or cloudy parameter as the white balance, your image will immediately a warm color and dominant ( more intense reds and yellows ).

PS: with artificial light things are a little simpler , in fact the next time you go to the mall try to check the technical data on the light bulbs on sale, they usually also indicate the radiated color temperature to let you understand if it will shed light cooler ( blue ) or warmer ( yellow ).

4. The Direction of light

The direction of the light on our subject is essential to determine the final result of the shot. Depending on the direction of the light we will get completely different photographs. So let's examine the differences on the subject caused by lights coming from different directions.

Front light

It is the most widespread situation (thanks also to the built-in flash on the machines) but it is also the least effective. The light is flat, devoid of shadows and lacks three-dimensionality. The photos will therefore be trivial and devoid of charm.

Side light

Lateral light is widely used in photography precisely because it lengthens the shadows, giving a three-dimensional look to the subject. The only precaution is to check the contrast between the illuminated part of the subject and the one in shadow. Avoid double side lighting which would cause ugly double shadows, it is better to use a reflective panel to lighten the part of the subject farthest from the light source.

Backlight

It is the frontal light to the camera, it is the most difficult light to manage but also the most creative and particular. We just need to avoid that the light source directly hits our lens otherwise that bad effect called "flare" will be created. When photographing against the light, our subject will be between us and the light source therefore, if we let the camera choose the exposure and we don't use the flash, we would create what in photography is called a silhouette.