The diaphragm is one of the parts of the camera lens, it takes an important part in the "construction" of the image. What it is, how it works and how it can be used is a must for every photographer who is discovering the wide range of shooting possibilities with manual settings.
What is aperture and how does it work
To understand how aperture works, it is important to understand how cameras generally convert incoming light into an image. In order to better understand the principles of the camera, it is better to give an illustrative example.
Imagine a completely dark room that has a black glass window that does not allow light to enter. If you open it a little, leaving a small gap, you will see a thin strip of light on the opposite wall. If you open the window completely, then the whole room will be filled with light. In both cases, the window was open, but the lighting characteristics are completely different. In the camera, the diaphragm plays the role of the window, and the matrix that captures the image plays the role of the wall on which the light falls. How wide the aperture is open determines many of the characteristics of future photography. Many, but not all, as the diaphragm is not the only element involved.
What does a diaphragm look like? This is a flap, assembled from the so-called "petals", which, rotating around the circumference, form holes of different diameters (see attached photo). Remember the window analogy? The size of the round hole, which is formed by the movable petals, is the same as the opening width of the window. The diaphragm can be composed of a different number of blades, and this also plays a role in the construction of the image.
How to use the diaphragm
In the camera settings and on the lens markings, the aperture characteristics are indicated by the letter f with its assigned numerical values, for example: f / 1.2 or f / 16. It is important to remember that an inverse relationship is used here, that is, the lower the number, the larger the aperture opening (the wider the “window” is open). Thus, a value of f / 1.2 means that the aperture is wide open and a lot of light will hit the matrix, and f / 16 - little. It is important to pay attention to the f / mark when choosing a lens. The lower the value (based on standard f / 3.5), the better.
When the aperture is maximally open, a large amount of light enters the matrix. This allows you to take pictures in low light without using flash and long exposures. By the way, shutter speed is a time interval that determines the time during which the camera shutter remains open, letting light through to the matrix. Returning to the analogy with a window, this is the time during which you will keep it open.
In addition, the width of the aperture opening determines the depth of field. To put it simply, this is the number of objects in the frame that are in focus and have clear, sharp edges. With a wide open aperture, the number will be small. Surely many have seen portraits in which a person is captured clearly, and the background is blurred. Or only a small detail of the subject is in focus, and everything around remains blurry. In photography, this beautiful effect is called "bokeh".
With the apertures as wide as possible, you can focus on the smallest details, and all other light sources in the picture will blur into multi-colored round dots. Now is the time to go back to the aperture blades. The more of them (in standard, inexpensive lenses, there are usually five to seven of them), the more round the hole they form, and the softer the blur will be.
Unlike wide openings, a covered aperture provides a greater depth of field, which means more subjects will be in focus. This is widely used in photography when it is necessary to show all the details, for example, architectural or landscape.
Also, these aperture settings should be used when shooting at night with a tripod and long exposures. Not in low light, but at night when the number of light sources is minimal. The narrow aperture allows you to take clear pictures without "overexposure", in which all the details are visible.
Knowing the theory, it's important to experiment with different apertures yourself. By seeing the difference in the pictures, you can learn to choose the right value for different conditions and always achieve great results.
