With this, I start a new thread of articles which explore creativity in photography. Until now, most articles penned by me have been restricted to the threads "Let's get technical" and "Blasting the myths" which dealt with laying down the technical fundamentals and clearing the mist around photography resp. Along the way, I believe I have chalked out a sound understanding of photography and laid the foundation for the next generation of posts.
Simplistically speaking, perspective is the spatial distance between objects in the image, that helps you judge the spatial placement/location of the objects and their heights/forms relative to each other. Perspective is affected by the focal-length & subject-to-lens distance combination. You can alter perspective by either moving around or by changing the focal-length of the lens or both.
How to alter perspective?I'd say that more than focal length, it is the subject-to-lens distance that determines perspective. After all, change in focal length is an eventuality that follows when you change the distance. Unleash your creativity with perspectives by moving around the subject and clicking from various distances while maintaining the subject's height/width the same across images. You will notice that if you kneel down and click a standing person's pic from a close distance, the person looks gigantic as compared to his/her surroundings. This attributes a larger-than-life or a heroic feel to the persona of the subject. On the other hand, if you click the same subject by standing on a stool and looking down at the subject, he/she appears dwarfed, which creates a sense of suppression.
How perspective is used in movies
This is where the director of photography in movies/sitcoms comes into play. Using a telephoto lens, the director positions the actor far away from the lens. When the director zooms in on the actor through the telephoto lens, it looks like the oncoming truck is right in the actor's tracks and is going to overrun him when in fact, they are on parallel tracks made to look superimposed because of the manipulated perspective (zooming into an object from a distance flattens the perspective, thus making things look closer than they are). Also, when the director wants to show an actress/actor along in a dense area like a forest/garden, he uses a wide angle lens to introduce more depth in terms of perspective into the frame.
So choose a position because of what it does to the perspective; then choose the focal-length/zoom. The next time you click a pic, remember the "perspective" concept and put some thought into the composition of the image. I guarantee that you will like the entire process of photography even more down this road :)