Fundamentals of photography: diaphragm, durability, light sensitivity – the exposure triangle

Basics of Photography: Diaphragm, Durability, Light Sensitivity - Exposure Triangle

To begin with, all these elements have been key terms in photography from the moment of its creation and remain unchanged today. Given these basic principles, you can create beautiful photographs. If you need to remove certain types of images, you may need to sacrifice something to organize your priorities. It is important to know what all these terms mean at the moment you need to make the right choice.


diafragma f

The lens diaphragm is the hole through which light passes into the sensor, indicated by a numerical value of F (e.g., F/2.0 or F/2.8). The smaller the diaphragm, the larger the hole and the more light that passes through the lens, resulting in better camera performance during low-lighting conditions. The number shown in the specifications is the maximum number of diaphragms for this focal length (for the following focal lengths).

For example, if a camera is removed at f/5.6, it will be less light than at f/2.0. An f/1.8 lens can be called a “light core” lens. This means they can shoot at higher shutter speeds. The higher the lens aperture (the lower the diaphragm count), the better the lens is suited for shooting inadequate scenes inadequate scenes. Therefore, choose a camera with the smallest diaphragm count (f/1.8 is better than f/2.8).

A zoom lens, for example an 18-55 mm camera, will almost always give two sets of numbers, such as f/3.5-5.6. This is called the diaphragm variable. The first diaphragm number indicates the maximum diaphragm when shooting at the widest angle and the minimum focal length is 18 mm, while the second value indicates the maximum diaphragm when shooting at the maximum focal length (55 mm). Diaphragms also change with scaling and focal length.

It is also important to note that for cameras with large sensors, the diaphragm value affects the depth of sharpness. Thus, with a large diaphragm, a small depth of sharpness can be obtained. Thus, it is possible to create beautiful blurry backgrounds, “sides” where the SO is covered. Unfortunately, it is almost impossible to achieve such an effect with a small sensor.

By: Domnique

Photo by Lothar Adamczyk /


The time the camera shutter is open and the light enters the sensor (the light-sensitive element) is called the exposure. For example, 1/60 second (long exposure) exceeds 1/2000 (short exposure). The longer the endurance, the more light is exposed to the sensor.

The diaphragm and the excerpt are closely interconnected to each other and are referred to as “expopara”. With short exposures, the picture becomes uneasy (dark) and if the shooting is done by hand, will be long re-specified (too bright) or lubricated due to shaking the camera.

By: Domnique

Photo author: ario wibisono /

By: Domnique

Photo credit: Leonardo Fava /

Light Sensitivity (ISO)

This is a unit of measurement of a camera sensor’s sensitivity to light; the higher the number, the more sensitive the sensor. For example, a camera sensor at ISO 3200 is more sensitive to light than at ISO 200. This allows frames to be created in poorly lit conditions, but at the same time the pixels will appear stronger and warmer as a result. Such phenomena, like “noise,” appear in the form of multicolor points.


Exposure, diaphragm, and light sensitivity are the three main factors that need to be considered in setting the exposure. This is the S O-CALLED “exposure triangle”. Exposure is obtained during the interaction of these three elements and is in the center of the triangle.

Exposure Triangle

Most importantly, all these elements are in dense interaction with each other and one cannot ever emphasize just one of the main elements. Understanding the exposition is less complicated because many people use the ratio phor to describe the ISO, excerpt, and diaphragm. We will share two metaphors with you to better understand.


Imagine that the camera is a window that opens and closes blinds. The diaphragm is the size of the window. The larger the window, the more light falls through it and into it. Exercise is the number of hours, the blinds are raised by the light, entering and illuminating the room. Now imagine you are in a room with sunglasses (I hope you can imagine this). Your eyes are not less sensitive to light (same thing happens at lower ISO values). There are several ways to increase the amount of light in a room. First, you can increase the amount of time the blinds are open (i.e., increase exposure). Open the window wider (increase the diaphragm) or remove the glasses (make more ISO). Maybe these are not the best comparisons, but at least you got a good idea and understood the principle.


Photo author: Sanchez

Some people burn very quickly in the sun. Some people cannot sunbathe. Figuratively speaking, your type and its skin sensitivity can be compared to the ISO value. In this example, the shutter speed (excerpt) refers to the duration spent in the sun. Those with more sensitive skin should spend less time in the sun or sunbathe in the morning. If the sun is less active, i.e., the diaphragm is closed, the exposure and value of ISO can be increased.

Understanding the interaction of exposure, diaphragm, and ISO requires constant practice. In many ways, it is based on intuition and luck, and even the most experienced photographer can randomly configure the camera, not always providing all options. Keep in mind that changes in each element not only affect changes in exposure to the image, but also affect other points in the picture. For example, a change in the diaphragm will change the depth of sharpness – the smaller the hole, the greater the depth of sharpness. High ISO adds noise to the photo, and removing it from your hand too long will lead to lubrication of the photo.

The most remarkable thing about digital cameras is that they are the ideal choice for studying exposition. You can take pictures with different values of one or the other parameter. Remember that you do not always have to shoot in automatic mode. There is also a manual mode and a semi-automatic one, where you can choose the priority of the diaphragm or of the excerpt. In this case, you can manually set the camera with a value for one of these components and the camera will automatically select the required values for the other components.

And now you know about the important components that affect the quality and attractiveness of your photos.

By: Domnique

Photo credit: mal smart /

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