Not exactly, we don’t need to understand photon and stuff. We just to understand the basic and how it effects a photograph.
Light from a source, reflected by an object is captured by our eye.
Now we add in a camera in front of the eye and the scene is recorded on device sensor.
Understanding the source is important as it will help you determine the overall mood and other aspects of a photograph. And there is no good or bad light source. If you ask a landscape photographer, he will tell you natural light is the best. If you ask the same question to a studio portrait photographer, he will swear by artificial light.
(Disclaimer – I shoot exclusively with available light, if you are looking for advice on external flashes and lighting systems, I am not the correct guy to follow)
|Light Direction One|
Here the light source is on top with beamed light falling on the subject.
Here the light source is coming from top right, as you can make out from the direction of shadows. The intensity of light is also hard and close to subject, which you can make out as the bell on right got more light than the left one.
Leaving three four images for you guys to dissect in comment section. Give it a try will be a good exercise.