Written By: Vishal Parvannan
Photo via Unsplash.com
Introduction:
Cameras are the pinnacle of modern society. It is used to take photos of family or friends, take selfies, or show history and the change of life over time. Originally, there were film cameras, cameras with the sole purpose of taking pictures and storing them in their memory. Today, mobile phones have access to cameras that are much more advanced. How are phones and older cameras able to take photos? How can a 3D object be encapsulated onto a device to a 2D image?
The First Camera
The first idea of a camera was not an actual camera like today. It was a room, typically darkened for more effect) with a small hole on one side of the wall. The light from outside would be able to pass through that hole, and as the light is reflected in straight lines, it creates an upside-down image on the opposite wall. This is similar to a projector, where the light is projected onto a screen. Even though there was an image, the first camera took 8 hours to take a photo and it was still blurry. To take clear, adjustable photos with the click of a button, camera lenses were created.
Taking In Light
Light can either reflect off an object or pass through it and change directions. Camera lenses are made with glass, a material that reflects light. The light hits the sensor, divided into millions of megapixels, and converts it into energy. Each megapixel can be read to determine the intensity of light, which adds details to the image. More megapixels means that there is more detail in the image taken. Each color of light has a different amount of energy, which the film reads to determine the lighter and darker areas of the image. By manipulating the angle of the lens, it’s possible to redirect the light rays to one singular point, creating a sharp image. The sharp image is seen by the digital camera sensor or film. A lens contains an aperture, which can change the amount of light entered into the camera. A larger aperture allows for more light and a shallower depth of field, while a smaller aperture lets in less light but a greater depth of field. The aperture is necessary, as it creates a clear, sharp image for any type of view.
Focusing on Objects
Every camera has a focus, which uses the focal length to move the lens accordingly. The focal length refers to the distance between the lens and the image sensors, measured in millimeters. A lens with a longer focal length, found in telescopes, can be used to view objects the naked eye can’t see into a detailed live image. Modern devices have an autofocus system, where the device does the process on its own and adjusts the camera accordingly. When you zoom your camera far in or far out the camera takes a moment to adjust the lens so you can see the full perspective. Older cameras require the user to change the lens’ focus as it does not have the same automation process as cameras today.
How are images taken?
When you take a photo with a professional camera, you may hit a clicking sound, indicating a photo is being taken. The mechanism is a shutter that allows light to hit the sensor for a specific amount of time. Faster shutter speeds allow for more light, but create more blur and vice versa, which is why it’s important to understand both elements to find the perfect shutter speed.
A camera’s sensor captures light in an analog (voltage) form, which is converted to a digital form via an analog-to-digital converter (ABC) so the information can be processed by the camera’s processor. Since cameras see color in scales of RGB (Red, Green, Blue), the camera uses a process called demosaicing, where it generates an estimated color image that is closely related to the original one.
When the image is taken, it is saved as either a JPEG or RAW file. A JPEG file is better for sharing but smaller sizes, while a RAW file retains all the data captured by the sensor for more editing. These files are saved onto the memory card, which is typically an SD or CF card. Memory cards store memory, measured in gigabytes, and the more gigabytes it has, the more files it can hold.
Conclusion:
In short, cameras are able to capture images by directing all the light received into one sharp point onto a lens or film. The lens is able to record the scene’s details using millions of pixels. The data is processed, adjusted for color and clarity, and saved as a digital file to be shared, viewed, or edited. Each part of the camera works in harmony to turn a moment into a long-lasting memory.
Works Cited
Canon. “Canon : Canon Technology | Canon Science Lab | Photographs.” Canon Global, https://global.canon/en/technology/s_labo/light/003/01.html. Accessed 26 October 2024.
CreativeLive. “How Does A Camera Work?” CreativeLive, https://www.creativelive.com/photography-guides/how-does-a-camera-work. Accessed 26 October 2024.
ePHOTOzine. “This Cutaway Diagram Shows The Inside Of A DSLR.” ePHOTOzine, 3 February 2017, https://www.ephotozine.com/article/this-cutaway-diagram-shows-the-inside-of-a-dslr-30546. Accessed 26 October 2024.