[EN] Aperture and diaphragm: what they are and how to use them

Hi! If you're new to photography, you're probably trying to learn a theory just because you don't know where to start. In this article I will explain what the aperture and diaphragm are, and in the next 3 articles I will tell you about ISO, shutter speed and exposure triangle (how to harmonize these 3 basic pillars of photography). Let's begin!

What is the aperture?

The aperture is, technically, the hole through which light passes to the sensor of the device. Basically, the aperture controls how accentuated the bokeh effect (blur) is and/or if it exists. Most of the time you will hear photographers telling you, "Shrink the aperture a little!" Instead of "Shrink the diaphragm a little!" In principle, these two do the same thing.

What is the aperture and diaphragm?

The diaphragm is the one that controls the amount of light that enters through the lens. It is made up of blades and works on the same principle as the iris (when there is a lot of light, the diaphragm closes and lets less light reach the sensor, and when it is dark, the diaphragm opens to let in as much light as possible). In short, the diaphragm is the mechanical part of the lens that blocks light, and the aperture is the hole that allows light to pass through.

            

The aperture is expressed in numbers f (f/1.2 , f/8 , f/11 etc.). The numbers f are also known as "f-stop" and represent the aperture value. A small f-stop number (f/1.2 , f/1.8 or f/2.8) represents a wide aperture (the diaphragm open and more light enter), and a large f-stop number (f/11, f/16 or f/22) represents a narrow opening (the diaphragm closes, letting in less light). Therefore, the f-stop number and diaphragm size are completely opposite. 

To find out what "f" your lense has, you need to look for an inscription like 1: 2.8 (for fixed f lenses,) which shows that the f-stop number is 2.8. For objectives with variable f you will have to look for an inscription like 1: 1.8-4, which shows that the f-stop number is between f/1.8 and f/4.

What is depth of field?

As I said at the beginning, with the help of the aperture you can control how blurred the background of a picture should be. This "technique" is called depth of field.

This depth of field is influenced by the aperture value. The higher the f-stop number (f/11, f/16 etc.) the clearer the background of the image. The lower the f-stop number (f/1.8, f/2, f/4) the subject will be better cut from the background covered with the bokeh effect.

In conclusion, if you want to photograph a landscape you will use a large f-stop (from f/8 upwards), and if you want to take a portrait or a macro photo you will use a small f-stop (from f / 1.2 to f /4).

I will stop here with this article which is already longer than I expected :)) In the following articles I will talk about shutter speed, exposure and ISO. Until then, try to perfect your techniques and take as many beautiful pictures as possible! Byee!😉👋