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    How does a camera work?

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    Aina Prat Blasi

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    Do you always use a camera, but do you know how it works? Photographers took nearly 1,5 trillion photos in 2021. The importance of cameras cannot be overstated in the 22nd century, but most of us don't know how these revolutionary devices work. So how does a camera work?

    Types of cameras

    Cameras have evolved from huge devices that required 15 people to use to being able to fit into our pockets.

    For most people, smartphone cameras are more than enough to get the job done. But for professionals and enthusiasts, nothing less than a DSLR will do. Today, the most popular types of cameras include:

    1. Fotocamere SLR (Single Lens Reflex): SLR cameras use a single lens for all operations performed when capturing a photo composition, focusing and recording. The images recorded by the SLRs are captured on film.
    2. Fotocamere DSLR (Digital Single Lens Reflex): Using the same type of lens as DSLRs, these cameras record the captured image using a digital sensor. The images themselves are stored on a memory card instead of on film.
    3. Digital cameras: yes are point-and-shoot cameras that capture and record images using a digital sensor. While the image quality isn't on par with a DSLR, they are more portable and less complex to use.

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    Types of lenses

    Lenses are an important part of any camera. In some cases, they are more expensive than the camera itself. This is why it is important to know the different types of lenses and what they do.

    There are two basic types of lenses: fixed focal length lenses and zoom lenses. While primary lenses have a fixed focal length, zoom lenses contain multiple secondary lenses within them that allow for variable focal lengths. For this reason, fixed focal length lenses are cheaper and easier to carry than heavier zoom lenses.

    In addition to these, there are a few sub-types of goals that users should be aware of:

    1. Macro objectives: these lenses specialize in close-up photography and are primarily used for wildlife photography. The amount of detail captured by these lenses is unmatched.
    2. Teleobiettivi: a telephoto lens is used to isolate and capture distant objects at the cost of a narrower field of view. They are most commonly used in sports photography to focus on a single athlete.
    3. Wide angle lenses: Most commonly used in landscape and street photography, wide-angle lenses have a wide field of view and focus on everything in the frame.
    4. Standard objectives: the most common type of lens, a standard lens is an "all-rounder" that allows users to capture wide-angle and magnified photos. But none of this will be done like a wide angle or a telephoto lens.

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    How does a camera work?

    Each camera consists of three main elements: an optical element, an acquisition element and a recording element. The full picture that users see is the combination of these three. In a standard DSLR camera, the lens, image sensor, and memory make up the three elements respectively.

    Before understanding how cameras work, it will be helpful to familiarize yourself with some basic terms of photography.


    The lenses have apertures that let in light, and the aperture is the size of this aperture. A wider aperture allows more light to enter, and a smaller aperture allows less light to enter. To measure the aperture, the terminology f-stop is used. F / 1.8 is a wide aperture and lets in a lot of light, while f / 22 lets in only a tiny amount of light.

    Large apertures result in blurred backgrounds, with focus only on the main object. Narrow apertures, on the other hand, maintain the overall sharpness of an image. Aperture also affects how light or dark the final image will be - the exposure.


    Usually located behind the lens, the shutter opens and closes to control the amount of light the sensor receives. Changing the shutter speed affects the image in several ways. Basically, a longer shutter speed will result in a brighter image, but if something moves while the shutter is open, that object will become blurry.

    Digital and optical zoom

    There are two methods to magnify distant objects: digital zoom and optical zoom. Digital zoom uses software and the camera to zoom in on distant objects, while optical zoom adjusts the lens itself to zoom in on these objects. Basically, digital zoom is like cropping the edges of an image and zooming in on the center.

    In optical zoom, however, the lenses shift to achieve “true zoom” which results in superior quality. All smartphones use digital zoom, while DSLRs and SLRs use optical zoom.

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    Focal length

    Simply put, focal length is the distance (in millimeters) between the “optical center” of the lens and the sensor in a camera. A longer focal length will result in larger images and vice versa. Lenses with a longer focal length will have a narrower field of view but greater magnification than those with shorter focal lengths.

    For more details, be sure to read the photography terms every photographer should know.

    The process of acquiring an image

    Here's how a modern camera captures an image:

    1. When the user issues the capture command, the light bouncing off the scene in front of the camera is received by it.
    2. The light is then focused on a single point. The size of this depends on your opening.
    3. Light travels through the lens until it reaches the shutter, which opens to reveal the sensor behind it. Most cameras today use a Charge Coupled Device (CCD) or a sensor CMOS (Complementary Metal-oxide-semiconductor).
    4. The sensor then detects the different colors and converts them into the final image file we see.

    If you are looking to improve your photography skills, these key photography tips may come in handy.

    How does a smartphone capture an image?

    Smartphone cameras are becoming more and more advanced, but there is a big difference between them and DSLRs. For reasons of space, smartphones have an electronic shutter (e-shutter) instead of the traditional mechanical shutter.

    When you capture an image using a smartphone, your device tells the sensor to record the image for a specific time. Features like low light photo mode and optical image stabilization are all disabled by the phone's software. These are performed by manipulating the shutter speed.

    The cameras are simple

    While there are more variables that control how an image will turn out, the camera is by far the most important. That's why it's essential to know how they work so that you can use this knowledge to take better photos.

    Further Reading:

    • IPhone camera not working, how to fix
    • Galaxy A20 camera problems
    • Galaxy A40 camera problems
    • How to fix camera problems on Huawei / Honor devices
    • The camera does not work on Android, 7 solutions
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