If you master the aperture, you will have real creative control over your camera. Aperture adjustment is the main culprit behind many beautiful photographs and the place where the difference between one-dimensional and multi-dimensional images is made.
The aperture is the size of the lens opening at the time the photo is taken.
When you press the shutter button on the camera, a hole opens in the lens that allows the camera sensor to cast a glance at the scene you are shooting. The aperture you set determines the size of that opening. The larger the hole, the more light will fall on the camera sensor.
The aperture on the lens is also known as a “diaphragm.” It is an ingenious fruit of mechanical engineering that provides a variable-size opening on the optical path that can be used to control the amount of light passing through the lens.
For given shutter speed, lower illumination requires a larger aperture to get more light to the image sensor, while stronger illumination requires a smaller aperture to achieve optimal exposure.
Alternatively, you can maintain the aperture setting and adjust the shutter speed to achieve similar results. However, the aperture provided by the opening also determines how much light passing through the lens will be. This directly affects the depth of field, so you will need to control the aperture and shutter speed to create the images you want.
The aperture determines the amount of light reflected from the recording subject that will reach the film or its equivalent.
By adjusting it, we try to ensure that the film always receives approximately the same amount of light, regardless of the light conditions in which we shoot.
If we succeed in that, we will have pictures with beautiful colors and precise details. If we miss, the images will be highlighted (dark) or too light (pale).
Not to be confused, the largest number on the ring that adjusts the aperture is the smallest aperture and vice versa.
To make all of this more understandable, look at it this way:
- If it’s sunny weather and you’re taking pictures in the sun, the reflected light will be strong. Therefore, the aperture must be reduced. Set the aperture ring to the highest number (16).
- If it’s dusk, you will adjust the ring to the smallest number (2.8). Thus, the numbers on the ring correspond to the illumination conditions and inversely proportional to the aperture.
How is aperture measured
The aperture is measured in f-stops defined by numbers such as f-2.8, f-4, f-5.6, f-22, and so on.
Switching from one f-stop to the other to increase or decrease the size of the lens aperture, and therefore the amount of light entering the camera.
Note that a change in shutter speed (shooting speed) also doubles or increases the amount of light that falls on the camera sensor.
This means that if you increase the aperture and decrease the shutter speed or vice versa, you will release the same amount of light – which can prove very practical in fieldwork.
One of the things that easily confuses many new photographers is that
Small numbers indicate the big aperture (where a lot of light goes in).
Large numbers indicate the small aperture (where a little light enters).
This means that the number f / 2.8 indicates a much larger aperture than the number f / 22. However, after a little practice, you will get used to this inconsistency.
Depth of field and aperture
“Depth of field” refers to the range of distances from a camera within which the subjects photographed will look reasonably sharp.
In extreme cases of shallow depth of field, the depth of focus can be only a few millimeters.
As an opposite extreme, some landscape photographs with an extremely deep depth of field can be taken, with everything sharply focused, from the space directly in front of the camera to objects many miles away.
Depth management is one of the most useful techniques available in creative photography.
Larger apertures give a shallow depth of field, so if you want to take a portrait with a beautifully focused background, you will need a wider aperture.
However, there are other factors.
Lenses with longer focal lengths can usually give a narrower depth of field, and the distance between objects in the scene you are photographing also affects the perceived depth of field.
Aperture and photo styles
Some styles of photography require a greater depth of field.
For example, in most landscape photos, photographers will choose a small aperture (large numbers). This will ensure that everything from the foreground to the horizon is in focus.
On the other hand, in portrait photography, it looks very nice when the subject is in focus, but behind it is a beautifully blurry background.
This ensures that the subject is in the main focal point and is not distracted by the other elements in the photo. In this case, you would choose a large aperture (small number) to get a small depth of field.
Macro photography, almost as a rule, uses large apertures to ensure that the subject in the photo completely captures the viewer’s attention, while the rest of the picture is entirely out of focus.
Exposure and Aperture
Exposure is the ratio of aperture (amount of light) and shutter speed (duration of light). Exposure is the total amount of light that enters the apparatus.
- If the exposure is too high, then too much light (either quantitatively or induration) gets into the camera, so we get an overexposed photo. This means that the picture is too bright, so most of the bright surfaces look completely white.
- If the exposure is too low, then there is too little light in the camera, so we get an underexposed photo. This means that the photo is too dark.
If the image is too bright, it may mean that we have opened the aperture too much (we have let too much light into the camera), but it may also mean that we have put the shutter speed too low (it has remained open for too long, so it has let out too long light into the apparatus).
Exposure is typically seen on the digital camera screen as a single horizontal scale with adjustments, above which is the slider. If the slider is right in the middle, then the exposure is about as large as the camera thinks it should be. If the slider is too far left or right, you’ll get a dark or light photo.
If the dot on the photo is in the middle of the scale, it is called natural exposure. If we then increase the shutter speed (less light), the dots will go left, and the photo will be underexposed.
To fix this, you will open the aperture a little more, thus compensating for the exposure. In the same way, if we change the aperture, then we compensate for the exposure by changing the shutter speed.
The professional photographers use another trick: whenever possible, adjust the aperture when taking a photo that gives the highest sharpness with a given lens. For most lenses, it is by about two apertures (two f-numbers) less than the maximum (meaning the f-number is larger by two apertures).
For example, if you had an f / 2.8 lens, you would get the sharpest images with f / 5.6 and f / 8 aperture (two apertures less than f / 2.8). Of course, you can’t always choose these open apertures. Still, if you are in a situation that you can, this way, you usually get the sharpest images your lens can take. However, this is not usual with all of the lenses.
Tips for using aperture
Taking pictures with a beautifully defocused background is more complicated than simply selecting a bright lens and fully expanding the aperture. This is the first key factor, but sometimes a large aperture will not produce the desired results. Another key factor is the distance between the subject and the background. If the background is very close to the subject, it may be covered in depth of field or be so close that the amount of defocusing is not sufficient.
Whenever possible, leave as much distance between the subject and the background you want to defocus. The key factor is the focal length of the lens you use. As mentioned above, it is easier to reach a narrow depth of field with longer focal lengths, so take advantage of this feature. Many photographers consider focal lengths between 75 mm and 100 mm to be ideal for capturing portraits with a finely blurred background.