Free visual guide to understand the aperture in photography This free resource is part of the pedagogical approach of the course Photography for beginners: professional technical bases, taught by Gerardo Montiel Klint, photographer and teacher with a solid international career. Industrial designer by training and member of the National System of Creators of Mexico, his work is part of collections such as the J. Paul Getty Foundation, the Museum of Fine Arts in Houston or the Museu de Arte Moderna in Rio de Janeiro, among many others. Throughout his career, Gerardo Montiel Klint has combined artistic practice with teaching in different Latin American countries, developing a way of teaching photography based on technical rigor, critical observation and visual sensitivity. In his Domestika course, he guides those who are new to photography to understand the essential fundamentals of the camera and to use them consciously and creatively. One of those key fundamentals is aperture, a setting that directly influences two essential aspects of the image: the amount of light entering the camera and depth of field. To facilitate the understanding of this concept, this free downloadable visual guide is offered, designed to accompany beginners in their first practices and help them make better technical decisions from the start. What is aperture in photography? Aperture refers to the size of the lens diaphragm opening, through which light passes to the camera sensor. It is expressed by values known as f-numbers or f/stop. - A wide aperture (e.g., f/1.8 or f/2.8) allows more light to enter. - A closed aperture (such as f/11 or f/16) limits the amount of light reaching the sensor. Although it may be confusing at first, the smaller the f-number, the larger the aperture. This setting not only affects exposure, but also the way focus is distributed within the image. How does aperture affect depth of field? The depth of field is the area of the image that appears in focus, from the foreground to the background. - With a wide aperture, the depth of field is shallow. The main subject appears sharp while the background is blurred, an effect often used in portraits. - With a closed aperture, the depth of field is increased and more of the scene is in focus, which is common in landscape, architectural or documentary photography. Understanding this relationship allows you to decide which part of the image to emphasize and how to direct the viewer's attention. How does aperture affect light? Aperture also acts as a regulator of light intake: - In low-light situations, a wide aperture helps capture more light without raising the ISO too much. - In sunny exteriors, a closed aperture prevents overexposure. Aperture control must always be understood in relation to the other two elements of the exposure triangle: shutter speed and ISO. Learning to balance them is essential to achieve correct exposures in any situation.
