How do Cameras Work? A Comparison of Cameras over the Ages

The first thing to understand about cameras is how they capture what is in front of them and imprint it on film or your phone. As we all know, cameras have lenses. These lenses are normally curved pieces of glass or plastic to focus the light from in front of it into the camera. These lenses have shutters that prevent it from taking in too much light for the photo. When you take the photo, the light enters the lens and then the shutter closes, preventing any more light from entering and ruining the image. Professional photographers can change the speed at which the shutter closes in order to let more or less light in to change the image. Older cameras used to have rolling mechanical shutters, however, you could not use standard flash with them after you had them closing at a certain speed. Digital cameras have digital shutters which do not physically close. Instead, the camera reads the sensor’s data at an instantaneous moment in blocks, usually rows of pixels (smallest component of an image). This allows for super fast images (up to 1/32000 of a second). Digital cameras are advantageous here, due to having less mechanical parts in the camera. This makes the camera smaller and more compact, allowing it to fit on the back of a phone.

The next thing to understand is how you can set the camera to take an image a certain way using camera settings. The first aspect to adjust is the zoom. Zoom works by extending the distance between the lens and the point of convergence. The point of convergence is the point at which the light from the photo converges to a single point. By extending this distance, you can zoom into certain elements of the scene. Some lenses have more zoom or less zoom depending on focal length, measured in millimeters, which represents this distance between the lens and the point of convergence. Next, cameras allow you to modify the aperture. Aperture is the size of the opening of the lens. The light then moves into the iris. The iris is a series of mirrors that can fold in on each other or also expand out. In a camera, the aperture dictates how much light gets into the iris and therefore, into the film or sensor. The aperture opening is measured in f-stops. The lower the f-stops, the larger the opening is. As mentioned before, you can also change the shutter speed of a camera, regarding how fast the opening closes after the camera takes a picture. Another setting you can change is the flash. Some cameras have a light that brightens the scene to allow the camera to capture it better. There are different types of flash. One is strobe, when the flash turns on and off at a certain speed. Another is continuous flash, when the light is on for a continuous period of time.