Understanding the Science That Makes Photography Possible

As photographers, we often focus on the art of photography. But how well do you know about the science that makes photography possible?

As the old adage goes, “a picture is worth a thousand words.” To say that photography has been one of the most influential forms of communication in the history of humanity is an understatement. Today, photography is one of the most prevalent art forms found around the world. Throughout modern history, it’s played an important role in our ability to communicate and connect with one another. Photography is arguably one of the most effective means of conveying ideas. It has the ability to distill lots of information into a single frame. A single image can also transport us to far-flung corners of the globe. More images are created today than ever before. Despite the transition from analog to digital, however, the principles that make photography possible remain fundamentally unchanged. If you’re not familiar with the science of photography, this infographic by the Huffington Post has you covered.

The Photographic Lens

Photographic lenses control how the light is transmitted onto cameras’ sensors. As light passes through a lens, the different elements within the lens focus and refract the light onto the sensor where the image is recorded. You can control how your final image appears by using lenses with different focal lengths and magnifications.

Recording the Image

Resolution describes the amount of detail an image contains. The more pixels in an image, the more detail the image has. Analog films have a resolution that roughly equates to 20 megapixels. Some of the latest digital cameras have resolutions that far exceed that (i.e. Sony A7R IV and Fujifilm GFX 100).

Most digital cameras utilize the same basic design. A camera’s shutter opens, allowing light to travel through the lens and reach the sensor. Typically, a CCD or CMOS sensor is used. The image sensor records the optical light information and converts it into digital files. These files are the images that we see on the back of our cameras or computer screens.

Defining the Image

Aperture (Depth of Field or DOF)

  • Aperture controls the size of your lens’ opening and the amount of light that is transmitted onto your camera sensor
  • Wide Aperture (smaller aperture number):
    • More light is transmitted through the lens and onto the camera sensor
    • Depth of Field appears shallower
    • Background elements will appear blurred
  • Narrow Aperture (larger aperture number):
    • Less light is transmitted through the lens and onto the camera sensor
    • Wider Depth of Field, more objects are in focus
    • Background elements will appear sharper
  • Depth of Field describes the area in front and behind the object that you’re focusing on within which everything will appear in focus.

Shutter Speed (Duration)

  • The amount of time that the shutter on your cameras is open and exposing your camera sensor to light
  • Long Exposure
    • Your camera sensor is exposed to more light
    • Objects in motion will appear blurred
    • Great for showing motion (i.e. landscapes, astrophotography, etc)
  • Short Exposure
    • Your camera sensor is exposed to less light
    • Objects in motion will appear sharp
    • Great for freezing motion (i.e. sports, wildlife, etc)

ISO (Light Sensitivity)

  • Back in the analog days, ISO was used to describe the speed of the film you chose
  • Today, ISO describes a camera sensor’s sensitivity to light
  • Low Sensitivity
    • Most cameras start with a base ISO of 100
    • Great for situations with plenty of light available
    • You’ll tend to get the best image quality shooting at low ISO settings
  • High Sensitivity
    • Many modern digital cameras allow you to raise the sensitivity far beyond ISO 3200 or 6400
    • Great for low light situations
    • The higher the ISO setting, the more noise will start to affect the overall image quality

For more in-depth looks into how Aperture, Shutter Speed, and ISO work, check out the following:

By the Numbers

  • 27,800 photos are uploaded onto Instagram every minute
  • over 300 million photos are uploaded onto the Internet every day
  • over 6 billion photos are uploaded onto Facebook every month