How does the diaphragm of a camera work?

The diaphragm is one of the fundamental elements when it comes to taking high-quality photographs. A piece whose control requires certain knowledge both regarding its usefulness and the effects that its adjustment produces in our photographs.

In the world of photography, there are many elements that we can play with to take different images with attractive compositions. These elements can be external, such as lights, umbrellas, backgrounds and others, or internal or specific to the camera and the objectives that we are using. In this last section, is the diaphragm. This piece is basic to any lens or digital camera, which allows us to adjust the input of light when taking photos. Something that makes this element a key piece to take the greatest control over our photos.

However, unless you have training in this field, you probably don’t know much about this piece. To solve it, we leave you this article, where we tell you what the diaphragm of your digital camera is for (you can find here some options to compare), how to adjust it and other interesting information to make the most of its functions.

what is the diaphragm

The diaphragm is the element responsible for regulating the amount of light that enters the interior of the camera when taking a picture. Something essential to obtain different results, since a larger or smaller diaphragm opening will generate lighter or darker photos, depending on what your composition needs.

Without going into the more technical operation of a photography diaphragm, we can equate its approach to that of the human eye. More specifically to the iris, which is responsible for adjusting the amount of light we receive depending on the environment. However, there is a fundamental difference between the two. The iris is autonomous and responds automatically to changes in light, with the aim of preventing excessive luminosity from damaging sight, while helping us to see something better in the dark. However, even when the function of the diaphragm is the same, in this case we are the ones who are going to open this element more or less, allowing a smaller or larger amount of light in the composition that we are making.

What does f mean on a digital camera or lens

It is likely that when you bought your camera you have read something about f among its features. This f value informs us of the different apertures that the camera lens can offer. Depending on this value, we will have more or less light adjustments when taking photos.

Simplifying a bit, the f factor measures the focal opening of the diaphragm, being adjustable at different levels. They are measured using a normalized scale, taking values ​​such as 1 – 1.4 – 2 – 2.8 etc. However, the aperture values ​​are specific to each lens or camera, so some may have certain values ​​and other models take different ones. In any case, there are tables where these values ​​are collected. The larger the f value, the smaller the lens aperture and vice versa.

When we go from one value to another, the so-called diaphragm steps appear, which are also usually useful information when buying cameras and lenses. A product with 12 stops, for example, will allow you to set 12 different values ​​for the opening of that diaphragm. By the way, each of these steps involves doubling or halving the amount of light that enters the camera during shooting.

How to adjust the diaphragm

With all that said, you probably want to start playing with the light and see how an open or closed aperture influences your photos. However, before doing so, it is necessary to know how to adjust the aperture of the diaphragm.

In general, the adjustment of the diaphragm is carried out by turning the moving part of the lens, each of the movements that this lens allows being each of the steps that we have commented on previously. On fixed lens models, aperture adjustment is done through the device’s setup menus, so you’ll need to take a look at your camera’s instruction manual to proceed.

This same setting adjustment may be required on cameras with interchangeable lenses, in order to go from automatic to manual settings. Consider that the assistants that many of these cameras have automatically adjust the aperture of the photo according to the environment and light conditions, so if we do not activate the manual mode, you will not be able to make those custom adjustments.

Other implications

Until now we have talked about light, but the truth is that the greater or lesser opening of the diaphragm has other implications. The main ones have to do with the depth of field and the sharpness of the image.

To better understand the concept, let’s take the following example. In front of us we place some of the best micellar waters that we have at home or bottles of shampoos or gels and have the smallest part of the letter facing the camera. The idea is to have a large object but with smaller elements, to see how the image evolves as we play with the diaphragm.

If we take a photo of that bottle with a small aperture, with the diaphragm more closed, we will see how the sharpness of the letters on the label is less and we will also notice a shallower depth of field in the image. The reason is that, by having less light, we are also giving less information to the sensor when it comes to seeing what is in front of it.

On the contrary, if we take that same photo with a high aperture, we will not only obtain more light in the image, but we will also gain in sharpness. The result is that we will see the letters more clearly in the final photo. In addition, this greater amount of light also allows us to gain depth of field, so we will not only see that pot more clearly, but also the nearby elements.

This relationship is another interesting element to play with when taking photos of all kinds, as it helps us define more or less certain elements of the image. So, depending on whether we want more clarity or a less defined image, we can also adjust this parameter, beyond the light approach that we have been discussing. It’s all a matter of experimenting.