# Camera ## How old analog cameras work? They require **film**. The film is a light-sensitive material that undergoes chemical changes when exposed to light. To capture a photograph, the camera must allow light to hit the film. The amount of light is controlled by the **aperture**, and the duration for which the light is captured is known as **exposure time**. The shutter is a mechanical component that can be set up to allow light to project onto the film for a specified period. > [!info] > The film would eventually get completely white without a shutter. ![[Pasted image 20231014064523.png|An old film by Kodak|300]] ## How digital cameras work? They work very similarly to analog cameras. They feature a digital sensor (electronic) for capturing light. The mechanical shutter is not needed because the electronic sensor can simply "stop" receiving light; for night shots, the duration is longer. ## Focal length ![[Pasted image 20231014064355.png|Focal point|500]] The focal length of a lens is a measure of how strongly it focuses or diverges light to the focal point. In the context of photography and videography is a characteristic that determines the lens's angle of view (how much of the scene will be captured) and the magnification (how large individual elements will appear). It is usually measured in millimeters (mm) and is the distance between the optical center of the lens and the image sensor (or film) when the lens is focused at infinity. 1. **Ultra Wide-Angle Lenses (< 24mm)** 2. **Wide Lenses (24-35mm)** 3. **Normal Lenses (~ 50mm)** 4. **Telephoto Lenses (> 70mm)** ## Sensor - **Sensor Size**: The physical dimensions of the image sensor in the camera. Commonly measured either diagonally, or by width and height dimensions. *The bigger, the better.* - **Pixel Size**: The size of individual pixels on the sensor. Larger pixels generally capture more light, leading to better low-light performance and greater dynamic range. > [!info] > Having the Pixel size of 200 Megapixels means that every pixel receives only a fraction of the light compared to 12 MP (considering the same Sensor size for both). ## Exposure ### Aperture ![[Pasted image 20231015061721.png|Aperture|450]] Aperture in a digital camera refers to the opening in the lens through which light passes to enter the camera body and hit the sensor. It's one of the three main factors that determine the exposure of an image, along with shutter speed and ISO. The size of the aperture is measured in f-stops (e.g., f/2.8, f/4, f/5.6), and it works in a somewhat counterintuitive way: the smaller the f-number, the larger the aperture opening, and thus more light hits the sensor. A larger aperture (smaller f-number) will result in a shallower depth of field, meaning a blurry background, while a smaller aperture (larger f-number) will produce a greater depth of field, rendering more of the scene in focus. ### Exposure time/Shutter speed Typically measured in seconds or fractions of a second (e.g., 1/1000s, 1/500s, 1/30s, 1s, 2s, etc.). ### ISO ISO refers to the sensitivity of a camera's sensor to light. Higher ISO values make the camera sensor more sensitive to light, allowing for photography in lower light conditions, but they also introduce more noise or graininess into the image. - ISO 100: Base level for many cameras; ideal for bright conditions. - ISO 200: Also used in bright conditions, slightly more sensitive than ISO 100. - ISO 400: Suitable for overcast days or indoor environments. - ISO 800: Good for lower light situations, such as during dawn or dusk. - ISO 1600: Useful for indoor photography without a flash or low-light outdoor settings. - ISO 3200: For very low light conditions, often seen in newer camera models. - ISO 6400: Used in extremely low light conditions; expect higher noise levels. ## Lenses Smartphones don't have the full size sensor. Because of that, they have *XY mm equivalent*, it's usually a "35mm equivalent" figure. This is a way to express the angle of view of a lens in terms that are familiar and comparable across different formats. ### Telephoto Lens (> 70mm) Specialized for capturing distant subjects with a narrow field of view. > [!info] iPhone 13 Pro: 77mm equivalent - real 9mm. ### Normal Lenses (~ 50mm) Mimics the field of view of the human eye, offering a natural perspective. ### Wide Lenses (24-35mm) Captures more of a scene than a standard lens, useful for landscapes and interiors. > [!info] iPhone 13 Pro: 26mm equivalent - real 5.7mm. ### Ultra-Wide-Angle Lenses (< 24mm) Provides an expansive field of view, great for capturing large scenes or tight spaces. > [!info] iPhone 13 Pro: 13mm equivalent - real 1.6 mm. This lens is usually re-purposed also as **Macro camera** too. ## References - https://www.youtube.com/watch?v=NzE7qj20Xwo