Aperture is a dark horse for beginners in photography. Many of them get confused in the values and do not understand what specifically changes because of them (“f / 1.4 or f / 5.6 — what’s the difference??”). In this article, we’ll explain, without getting too technical, how aperture works, as well as a few interesting uses for it.
What is a diaphragm: in simple words about the complex
To make it easier to navigate when setting the parameter, it is enough to know about the technical device of the aperture only that this is a hole in the lens that transmits light to the matrix. The diaphragm works like the human eye: when we look at something in the dark, our pupils dilate, while in the light they constrict.
The aperture in the lens is almost like its pupil, which can be adjusted manually based on the specific situation. The values of this parameter are capable of introducing a novice photographer into a stupor, since the lower the number, the wider the hole is open.
For example, f/1.4 is much larger than f/8. This is a little inconvenient, but there is one elementary explanation that will make the indicator more understandable. Imagine, for example, that f/10 is a fraction of something whole (like 1/10). It turns out that at f / 10 the aperture in the lens will be smaller than at f / 2 (after all, 1/10 of the circle is much smaller than 1/2).
We figured out the aperture values, so you can move on to the methods of using it in practice.
1. Exposure, shutter speed and aperture — how to set
Adjusting the aperture changes the exposure. The wider the petals of the lens are moved apart, the more the light-transmitting hole in it is open and the more the matrix will be exposed. As a result, we get a brighter frame. Try it out by taking a series of shots of the same subject under identical lighting, changing only the aperture (shutter speed and ISO sensitivity). In this case, you will see how brighter photos are obtained with smaller apertures.
Accordingly, the wider the aperture is opened, the slower the shutter speed must be to achieve the correct exposure. It is also necessary to select the ISO sensitivity (ISO value), although the rule always applies for inexpensive lenses: the lower it is, the less graininess and noise in the picture. It is better not to set the ISO above 200–400 units. With professional lenses, you can work at higher values without noticeable deterioration in quality.
Thus, the exposure is controlled by the aperture, although this is not its main purpose. The main property of the aperture is to change the depth of field, or DOF.
2. DOF and camera lens aperture — how to achieve the desired blur
Depth of field (DOF) defines the areas of sharpness and blurring from the foreground to the background. Have you seen portraits where the background is completely blurred? All of them were shot with a shallow depth of field (or processed in a graphics editor, but that’s another story). When both the foreground and the background are clearly visible in the picture, it means that the photo was taken with a high depth of field.
To achieve bokeh, where the main subject is sharp and the background is out of focus, you need to open the aperture as wide as the lens can. This is especially appropriate for portrait photography, when you need to “blur” the entire environment and focus on the main character.
But there are also reverse situations when a small aperture is required (remember, these are high values). For example, it is necessary when shooting architectural objects or landscapes. We will talk about this further.
3. Aperture value in the camera when shooting moving objects
By changing the aperture, you can “freeze” or “blur” the movement, depending on the situation and the idea of the shot. A hole in the lens opens — more light enters the matrix. As a result, the camera, in order to maintain the previous exposure, shortens the shutter speed. This makes it possible to photograph fast-moving objects with maximum detail. This technique creates an interesting effect, as if moving objects in the camera are static. Although it is not always appropriate, as it is not able to emphasize the dynamics.
There is also a reverse situation when you need to “blur” the movement. In this case, you can use the technique of shooting an object with panning: you focus on an object and follow the camera in the direction of movement, and then take a picture. With proper skill, very dynamic shots are obtained: the main object is sharp, and the surrounding background is blurred. In this case, the aperture must be closed in order for the shutter speed to increase.
4. Open aperture in the camera in low light
When shooting in low light conditions, the ability to open the aperture wide can be very useful. For example, if you are photographing actors during a performance in a theater or shooting indoors with insufficient lighting, you will need to set the aperture lower.
For such situations, fast lenses are suitable — from f / 2.8 and below. They literally help the camera to see in the dark almost better than the human eye. With budget photography equipment, this effect cannot be achieved. For example, the aperture of a Nikon or Canon camera in kit lenses does not drop below f / 3.5, so it is more difficult to shoot in dark conditions with them than with high-aperture fixes.
5. How best to set the aperture and shutter speed in the camera for a family report or shooting children
If you are a beginner and you are faced with the task of photographing active children, you can give the aperture setting to automatic. The fact is that when moving objects in the frame, shutter speed plays a more important role. Set it so that the image of running children is not blurred in the picture (average value is from 1/125 to 1/500 s).
If you still want to control the aperture manually, first achieve such a depth of field that all the actors “fit” into it. Experience is important here: for example, it will be difficult for a beginner to shoot active children with a prime lens with an aperture of f / 1.4 or f / 1.8. But an inexpensive whale lens is much better for this: its depth of field will be quite enough (its aperture ranges from f / 3.5 to f / 5.6).
6. What is the aperture value of a digital camera to choose for landscape or architectural photography
In these situations, we start from the depth of field. If you need both the foreground and the background, we select a sufficient depth of field so that it covers all the key elements. In this case, we cover the hole to f / 11 — f / 16. If set even lower, sharpness may deteriorate.
When there is no foreground, and the subject is far away from you, it is better not to use the widest aperture. Instead, adjust the exposure by lowering the ISO. A tripod will also help to achieve the best result.
7. Portrait mode in the camera and aperture, or how to create a bokeh effect with it
When working with a posing model, you can safely “play” with the adjustments, thus choosing the best ones for an aesthetic shot. To get a beautiful portrait, isolate the subject from the background with a minimum depth of field and a blurred background. To do this, on a whale lens, open the aperture to the limit f / 3.5. If you have a fast prime lens, you can even close the aperture a little. For example, if it allows you to set f / 1.4, even f / 1.8 may be enough for you. This way you will increase the detail and get rid of chromatic aberrations.