How Does My Camera Work?

These days, you’d be hard pressed to find a person that doesn’t own some sort of camera. But considering the high number of camera owners globally, very few have a solid grasp concerning the machine’s elementary controls:

Listed below are a few terms and concepts that every beginning photographer should know as explained by Some Stuff Explained.

Shutter Speed

Shutter speed refers to the amount of time that a camera’s sensor is exposed to light. Light particles continuously flow from a light source, but the shutter inside of the camera acts as a gate that either blocks out light or allows it to be registered by the device. Naturally, the longer the shutter stays open, the more light will enter the exposure. For this reason, shutter speeds are often measured in mere fractions of a second. Other than controlling exposure, shutter speed also directly correlates to the amount of movement captured by the camera. Fast shutter speeds freeze motion in place, while slower shutter speeds blur action within the frame.

shutter letting in light


Aperture is the opening at the front of the lens. It controls how much light enters the camera by expanding and contracting, with smaller openings restricting light flow and larger openings allowing more light in. Aperture is measured in f-numbers, which refer to the ratio between the lens focal length and the diameter of the aperture.

increments between f-numbers


The image sensor is the technology inside of a DSLR that records the image. It resembles a chessboard in that it is made of thousands of tiny square parts called pixels. Each pixel measures the amount of light entering its corresponding area, and when combined together, the shading of each individual pixel forms a part of a full fledged photograph. Sensors also capture color through red, green, and blue channels.

image sensor recording light


ISO describes the camera’s amplification of incoming light. In short, the light that reaches an image sensor is converted into the data necessary to create a digital image file. When the camera receives “weak” signals bouncing off of subjects reflecting very little light, the sensor has the capability to increase the light signal in order to create visible data. Too much amplification can result in digital noise, which distorts existing image pixels.

ISO analogy


Stops are used to measure the amount of light that reaches an image sensor based on the camera’s shutter speed, aperture, and ISO settings. Each stop increases or reduces the incoming light by a factor of two. For instance, a stop lower from a shutter speed of 1/500 of a second would be a shutter speed of 1/1000. Likewise, a stop higher than 1/500 of a second would be 1/250. Stops can be adjusted through any of the factors that effect an image’s overall exposure.

graph showing stop differences

Exposure Value

Exposure value (EV) represents the camera’s aperture, shutter speed, and ISO in a numerical form. Images with the same EV will allow the same amount of light to reach the camera’s sensor, regardless of which settings are adjusted to attain the EV. Adjusting the camera’s EV by one or two stops will therefore bring the exposure of an images up or down one or two stops.

demonstrating EV

Understanding these core controls brings sense to the photographic process. Take the time to get to know your camera and learn how these factors affect your images. You’ll take dumb luck out of image making equation and replace it with skills that can carry you through the duration of your journey as a photographer.

Like This Article?

Don't Miss The Next One!

Join over 100,000 photographers of all experience levels who receive our free photography tips and articles to stay current:

One response to “How Does My Camera Work?”

  1. Brian Palmer says:

    Thai is the best discussion of camera basics I have ever seen. It covers {almost) everything you need to know and it does it correctly.
    IMHO, as a teacher, the presentation is a bit too fast so a beginner may need to watch it several times to absorb all the information but that is OK

Leave a Reply

Your email address will not be published. Required fields are marked *