Surely it is not the first time you hear about the importance of focus when composing an image. How it highlights some elements above the rest, the ability of the focus to highlight the center of interest of the compositions.

Sure you also hear the term opening, because in this blog we always try to become a daring photographer and you dare to shoot in manual mode, so you can control yourself all the variables of the shot.

And surely also that, if you have dared at some point with the semi-manual or manual modes of the camera, it sounds to you that there is a relationship between the aperture and the focus. In case you have a little forgotten, before starting, we will refresh the basics.

Diaphragm opening
It sounds fatal and smells of something impossible to understand, but the truth is that the opening of the diaphragm is simply the opening through which your objective lets in the light. The bigger this hole, the more light will enter through the lens, and the closer it is, the less light will enter, just as the more you open a tap the more water comes out, and the closer you close it, the less.

That is the first concept that must be clear with the opening, when more or less light enters and the possibilities offered by playing with this knowledge. For example, in a scene where you do not have enough light, the ideal thing is to help the diaphragm to let in as much light as possible through it. This is done by opening the diaphragm (low f-values). On the contrary, if you have more light, the logical thing is that you close the diaphragm to avoid too much light through it (high f values).

But not only controls the entry of light that passes through the lens, but also controls what we know as depth of field or area focused on the image, ie, controls the focus. That is why it is important that you are clear that to control the focus you have to know how to use the opening. Once this brief review is done, let’s see another of the most important compositional decisions: Where to put the focus.

Where do I put the focus?
Because so important is the decision of how much of the area focused on the image we want, as where we want it because, as we already said at the beginning of this article, the focus is used to highlight and reinforce the centers of interest in the image. Now, it is not always easy to know what to focus on and in what quantity, let’s look at a few more or less typical situations in which a correct use of the focus will help you improve your photographs.

Individual portrait
Surely if you follow this blog, you have already heard our insistence at the time of focusing well on the eyes of the person portrayed. In the gaze is the strength of each one of us, it is the most expressive part, the one that we instinctively look for when we analyze a portrait, in which we most stop when we look at it. That is why, unless you look for another sense, unless you want to highlight another part of the scene for a specific reason, it is best to focus your eyes. If you also play with a shallow depth of field, remember to focus the eye that is closest to your goal.

Self-portrait
Since the artist behind the camera stands for a time in front of it, it is difficult to work with small depths of field, because in the self-portrait we lack the most important part of the photographic equipment, you. So it is best to work with half-diaphragm openings to ensure that the face will be well focused, because although it is a somewhat unusual portrait, for compositional purposes follows the same “rules” as a “normal” portrait.

You can help yourself with some tricks for focusing, dolls, marks on the floor, mirrors, etc. to help you adjust the focus of the scene. The most advisable thing is that you approach from a tripod and manually, and then you place yourself in the exact place you marked.

Landscape
In landscape what we usually look for is the greater sharpness and area focused on the image. For this, we not only use small diaphragm apertures (high f values) but also what we also know as hyperfocal distance. Or what is the same; the place where we place the focus to achieve the greatest amount of sharp and focused area in the image. To calculate it depends on several factors, including the distance to which we place the focus, the focal length of our optics, and so on.