Starting to Focus: Depth of Field

Last time we talked about the common scene modes that you may have in your camera. These scene modes were created to enable your camera to adapt to certain situations such as enabling you camera to focus on closer objects for macro mode or putting your camera on a lesser aperture to blur out your background in portrait mode.

Other common scene modes include sports mode, night or night portrait, landscape, and your full auto mode. We also learned that some of the other special scene modes simply combine the concepts of two fundamental scene modes such as fireworks mode.

We said that by learning how these scene modes specifically adjust your camera, we will be able to take a step closer to better manual photography. Furthermore, once we practice the applications of scene modes, we will slowly transition to our own style of photography with our own tweaks.

Learning the scene modes serves as a checkpoint in our lesson because from here on we will now be discussing the core fundamentals of photography. To kick things off, what we will be talking about today is an element that we have touched on a bit last lesson and that is the depth of field.

We may have not mentioned the concept of depth of field explicitly last lesson but you may recall reading about how the camera is able to change focus points to blur backgrounds or show them.

Well, that’s depth of field.

Focusing on focusing 

Last time we talked about the portrait and landscape modes, right? On a basic level, we talked about how they adjust your camera in such a way that will enable it to focus on one object or focus wider for landscape shots.

As mentioned, if you have read all the previous articles before this then you should have the right foundation already for more advanced concepts. During the previous lessons we simply described focusing as a general concept but today we will dwell on it more by studying the concepts under it.

By learning about depth of field, you will now be able to tweak your camera more manually and somewhat produce portrait or landscape shots on your own without the use of their respective scene modes. Furthermore, the concept of aperture is part of THE triumvirate that you will carry forever which includes the ISO and shutter speed.

Depth of Field

On a beginner’s level, focusing is basically avoiding a blurry photo. However, now that you are past that stage, we will now be talking about the depth of field. More than focusing, depth of field is concerned with what is focused, what is not focused, how wide or narrow you want your focus to be, and basically how to manipulate focusing.

What an upgrade, right?

Aperture

So the first thing we will discuss today to fully understand is the aperture. We mentioned this last lesson and if you can still remember it, the aperture translates to the world “opening” which refers to your lens diaphragm.

The lens diaphragm is your lens’ gate much like your shutter. However, unlike the shutter, your aperture is initially open and remains that way. This mechanism works together with your shutter speed in order to manage the light coming in.

F-Stops

Your aperture is measured in f-stops which is your focal length divided by the diameter - an equation that may only be useful for additional knowledge and to follow the logic. What you really need to know is what those number signify.

The greater the number, let’s say f/16, the smaller the opening is which means lesser light will be initially allowed to enter for the shutter. On the other hand, the smaller the number is, f/2.8 for example, the bigger the opening is and the more light to be allowed.

Your depth of field are greatly affected by these two and I will explain it in the most logically-sound way. You may think that because you aperture has a wider opening, it will automatically yield more sharp areas as compared to a smaller opening but that’s not the case.

In fact, it is the exact opposite.

The smaller your f-stop number is, the less sharper your background will be which is why portrait modes would prefer around f/2.8- 3.5. The technical reason for this is one whole new session for lens physics but the important thing you need to know is that your camera can only focus on one point. When you can only focus on one subject, the rest becomes peripherals and a bigger opening means more peripherals.

On the other hand, if you narrow down your opening, you increase the capabilities of your camera’s focus by “making your scene smaller thus enabling your camera to focus on a bigger area.

Apply and Adjust 

Understanding this one on paper can be quite hard and I suggest you get to your camera to practice the concepts we just mentioned. Try out putting a subject around 15-20 inches away from your lens and another 15-20 inches away from its background. Set up a tripod and shoot at f/3.5, f/8, and f/16. From these three photos you will notice that f/3.5 will have a blurred background and your focus widens to reach the level of f/16.

However, focus is not the only thing that your aperture affects and at the same time the aperture is not the only thing affecting your depth of field.

If you would notice, the narrower your aperture gets, the darker your photos come out mainly because a narrow opening will allow lesser light to come in. Furthermore, the larger the focal length you are using or the closer you are to your subject, the more you are able to blur the background.

That’s the lesson for today and we will be dwelling more on the concepts surrounding exposure next article. For now, just familiarize yourself with the depth of field logic and keep on practicing. Don’t forget to share this one with your peers as well!