Whether you are shooting with an iPhone or a $5,000 DLSR, knowing how your camera functions makes taking better pictures easier and fun.  At its core, photography is just capturing light, so learning how to capture light correctly can turn you into a very talented photographer! Here are a few fundamentals about how cameras give us the ability to capture the light efficiently.

In the days before digital cameras and smart phones, photographs were simply composed of the effects of contrasts, demonstrating how the sun changes the color of an object. Just think about a time that something that was left on the lawn too long changed the color of the grass due to the lack of sunlight. The concept is the same but the sensors in camera are so sensitive to light that light is measured in hundredths and thousandths of seconds instead of days.

A few components in cameras that change photo composition and dynamics are explained below.


  1. F-Stop: Aperture is the circular iris in the camera that enlarges or shrinks based on the f-stop number selected. The smaller the f-stop number, the wider the opening is that allows more light into the camera. Think of a backwards funnel, the wider the iris, the more light comes in from the sides. Conversely, the narrower the iris, the less amount of light can enter.
  1. Depth of Field: Depth of field is the second concept of aperture, which is the focal distance between objects. The best way to think about it is if you make that iris’s funnel wide, a lot of information is trying to come in too quickly, but if you narrow it down and let the information come in slowly, it is easier to read (or process) all the information to make a clearer picture.


The shutter is the door to the sensor of the camera that opens and closes based on the shutter-speed number.  It is gauged in seconds (1/250th of a second). The faster the shutter-speed, the more the motion is stopped.


ISO stands for International Organization of Standardization, which is just the main governing body that standardizes the rating for camera sensors. This is the sensitivity that the sensor has towards light. (Film used to be the sensor and was bought according to what ISO you wanted as the foundational point.) The higher the sensitivity the brighter the photo, but if the ISO is too high you will start to see grain or pixelization due to the sensor being put the max capacity of its sensitivity.

Camera Sensors:

Cameras have different sized sensors, Full-Frame, Cropped (APS-C) and Micro 4/3. The size of the sensor reveals how much data can be collected, usually the bigger the sensor, the more information can be collected. Also, if the sensor is a crop sensor, the lens is cropped based on its crop sensitivity. If you are using a 1.6 cropped sensor, your 50 MM lens becomes an 80 MM lens (1.6*50) which might make a difference when you are trying to get a particular shot.

By knowing the Megapixel data, you can tell how high-quality the camera sensor is. The quantification is determined by how many pixels can be read by the sensor. An 18 Megapixel camera is roughly 18 million pixels in the camera sensor. This number can also be found by multiplying the number of pixels of the image gathered. For example, if the photo is 5184px by 3456px, it is equal to 17,915,904 pixels or 17.9 megapixels.


Now that you understand the basics of how light is captured, you are a bit closer to correctly capturing images worthy to frame and display in your home. Even people who know everything about photography are not always the best photographers; great photos capture the right image at the right moment – and it is exciting to get that shot that tells the story you want to tell.

In future articles, I will explain exactly how aperture, f-stops, depth of field and sensors can be manipulated to achieve the results you are looking for.  I will break each concept down and demonstrate each one with a series of example images – before and after adjustments are made, so you can remember when and how to use each new trick. I would love to hear about and see your successes (or help you understand your failures).  Send your feedback to marketing@southernexposurephoto.com.

If you just put your camera on automatic settings and snap away, you might still get some great shots, but knowing more about how the camera works may increase the chances that your images will convey the right message and tell the right story.