The Basics Of Physics For Photography

The Basics Of Physics For Photography

Understand the basics of physics to photography is vital to understand how a camera and above all to make the most. In this chapter, as well as the next to be published, we will give, in a still surface, a general understanding of the principles that are the basis of photography, or the light, optics, electromagnetism and so on.

The light, photons, and the waveform

The nature of light was the subject of much speculation over the centuries. For Newton his nature was made of particles corpuscular ie, a theory but was not able to “adapt” to all the facts known about the interaction between light and the world around us For this reason it was short-lived, replaced by the wave theory of Huygens young. Subsequently, the physicist Planck discovered that many facts can be explained only on the assumption that energy is always emitted in discrete amounts, said many. The theory that ensued took the name of Quantum Theory. In modern times, interpretations of the phenomena of light is made in terms of wave quantum models. The quantum of light is called the photon.

Many of the properties of light can be easily predicted if we suppose it is a wave. A difference of sound waves (for which the air or any other physical medium in order to propagate) the light waves travel freely in the empty space at a speed of 2.998 × 10 ^ 8 meters per second (about 300 000 km per second). In the Earth’s speed loss it is negligible, while in the water is reduced to three quarters and in the glass to two thirds.


In space, however, it does not only light but there are many other waveforms, generically called electromagnetic waves. The electromagnetic waves propagate vibrating perpendicular to the direction of travel. For this reason it can be described as transverse waves, on the contrary of longitudinal waves (such as sound waves) whose direction of vibration is along the direction of travel. The distance between an intersection with the plane of rotation and a subsequent call is the wavelength of the radiation and is generally indicated by the Greek letter ? (lambda). The number of intersections with the plane of travel of the wave in one second is called frequency of vibration that is generally indicated by the Greek letter ? (nu). The speed of light is given by the following equation:

Finally, there is a third very important parameter that distinguishes one waveform, namely the amplitude: is the distance between the plane of rotation and the farthest point that the wave reaches before returning towards the plane of travel itself. The scale measures the intensity of the wave.

The figure above shows precisely the schematic of an electromagnetic wave. The electric field vibrates in the plane parallel to the running direction (Y axis), the electric one on the plane perpendicular to the axis (Z axis).

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