Depth of field; Cinema and Photography

Depth, well, it is one of the words that is analogous to many other things. While all the other secondary meanings of the word are related, the primary meaning would be ‘the distance between the top and bottom surfaces’. Even when it comes to a movie, the depth becomes a lot of things too. For suppose, the depth of a film can indicate the story going to deeper levels or the subject of the movie being deep. But we are particularly talking about the depth of field!

But technically, or to say, visually, depth or precisely depth of field is something that deals with focus. Depth of field is the field of vision that is in focus in a particular shot. Different camera lenses allow a certain depth of field. The aperture of a camera lens decides the amount of light that the sensor captures. Hard to understand, right? Let us break it down!

How does a camera function?

A camera is something that captures light through sensors. When you click the capture button, the light reflecting from the subject falls on the sensor. The shutter closes, and the captured light develops an image. Cameras are something that can control time with light. You can capture a moment of running time, and you can freeze that particular moment and hang it in your homes.

Aperture

Aperture is the hole of the lens. The light that passes from the subject is passed through the aperture of lenses before hitting the sensor. You can adjust the size of the aperture, and it affects the photo differently. When the aperture (opening) of the camera is wide open, it lets in all the light coming from outside. When more light falls on the sensor, only the subject appears clearly, and the rest of the background becomes blurred.

Because of the vast light that is going in through large aperture, this blurring of the background happens. And the blur occurs because the background is not in the depth of field. Depth of field is the area of focus in an image or a video. By making the aperture wide open and letting in more light, you decrease the area of focus, and only the subject of the image appears clearly.

depth of field and aperture

Similarly, if you decrease the size of the aperture, the light hitting the sensor is reduced. By each point of decrease in the aperture, the area of focus begins to increase. And if you tighten the aperture to the largest and closest, you can observe that now even the background is clear and not blurry. This blurring and focusing of subject and background happen because of the light going in and hitting the sensor.

F – stop

Something much more critical and confusing here is that the values of changing the aperture are referred to as ‘f-stops’. If you change the f-stops, the aperture either increases or decreases as per your requirement. The f-stops are fractions and are measured as f/1.8, f/2.8 and may have greater f-stops till f/22 or even higher. The common mistake one can commit while talking or understanding f-stops are about how they impact aperture.

It is clear to use that if aperture (hole) is wider then it lets more light in and the depth of field (area of focus) decreases. And if the aperture is close and tight having a smallest possible opening, it only lets little light and the depth of field increases. The f-stops with smaller numbers indicate wider aperture and the ones with bigger numbers indicate tighter aperture.

f stops and depth of field

It is that, greater the number of f-stop, lesser the opening of the aperture. And lesser the number of f-stop, greater the opening of the aperture. So, if you want to take a picture focusing only the subject and blurring out the background, you should choose lesser f-stop number on camera as it means that you are widening your aperture and letting more light. Thus, decreasing the area of focus, i.e., depth of field!

depth of field cheat

Wrapping up!

We have discussed how the depth of field is created, shifted and used to take pictures or videos. In the following week, let’s get into the practical use and ways of depicting the depth of field. We shall also see different types of uses of the depth of field to tell stories visually.

Understanding Cinema

What is a movie? We can define the term in several ways, but what is the actual operation and definition of a movie? Is it art? Or a Craft? To understand what it is, you need to have a perception of what ‘craft’ means and how it is different from ‘art’. A craft is an activity to create something. Many activities go behind the screen of a film, and all these activities are unhesitantly called crafts and the people who perform these activities are craftsmen. So is the film a craft? No! But filmmaking is a craft! Cinema is an art. This piece of art is made by various craftsmen combining their crafts such as direction, cinematography, music, sound, colour and various other aspects.

Cinema, the prodigal son of multiple arts

Now let’s strip down this art called movie to understand it in the right way. But before we do that, why did I use the term ‘right way’? Is there a wrong way? Yes, there is! The way we understand films impact a lot on what we are taking from it. If we understand cinema as a ramp, then we start taking the beauty of those ramp walking models, here actors. Somewhere we have lost our perception and movies have become nothing more than ramps. We have started watching movies to look at these sparkling actors. We have begun praying them, watching their films and defending their crappy works because we like them. Fanaticism is not our concern, though. So let us not worry about the wrong understandings of a film and dive into the proper way.

The Expression

Any art is an expression, and the artists are expressers. What they express is an artistic choice. But the purpose of art’s existence is to express something. Let us assume this expressing subject as ‘information’. Because no matter what the expresser (artist) chooses to communicate through their art, it conveys some information to the viewer. The entire purpose of a movie too is to speak something; to express some information to the viewer. Regardless of what that information is, every movie does talk about something. Like their ancestor, the painting, even a movie is visual art. It does speak something and its medium to communicate is visual. 

Cinema has the attributes of almost all the art forms. It is a visual art like paintings; has sound and music, and has characters, actions and spectacle like stage plays. They are the hybrid form of art, and it takes all of those artists to make it work. Sometimes when you hear certain music, it impacts you. It reaches your brain and triggers certain emotions. Music and sound are auditory art where they tell you something too. Some music has lyrics to say to you directly, and some music talks to you through its tune and instruments. Similarly, characters speak a lot of things through their dialogue and sometimes with their expressions. But when you dig into the actual lineage of cinema, you will understand that its heritage comes from paintings more than any other art. They are called movies for a reason. And that is, moving pictures!

person holding camera film
Photo by Luriko Yamaguchi on Pexels.com

The stripping down of cinema

When you strip down a movie, that is simplifying it. You can call a film as a collage of multiple video clips arranged in a particular order to tell a specific story. And if you strip that clip to its toes, a video is a bunch of photos taken at a certain speed and animated later. So all movie is just a bunch of pictures! Let us call these photos as frames! Because that is what a movie is. It has 24 frames per second, meaning 24 photos clicked per second. When you compile these continuously clicked photos into a clip and organise all these clips to tell a story, you have a cinema!

Note to film enthusiasts and aspiring filmmakers!

Now telling a story, that is where the difference lies. How do you tell a story? In a movie, you have all the arts available to you. You have many different ways to tell a story. It is up to you to make sure that you don’t over-use any aspect and never use any other. That is what happens in many mainstream cinema. They over-use ‘dialogue’ by conveying all the information through the character’s dialogues. It is an easy way out because the character directly speaks out. But you have all the other arts to use. When we strip the film down, we understood that it is just a series of photographs. What a photo is a modern version of paintings. 

With the available technology, we can edit all the details in a picture and convey some story even through a single photo. Now in a film, you have several thousands of images, 24 per each second. How fair is it to convey all the information through dialogue and character’s actions? Why not become more artistic by choosing to share information visually. Why not use music to say something? Why not use light, colour, make-up, properties and every other aspect that appears on screen to tell the story? Do use dialogues and do use character’s action, but in a film use all the available crafts equally to convey information, and that is a story!

To know more about my opinions on films, refer to the article where I have written about Om Dar-B-Dar (1988) and Satantango (1994).