Photography Guides: Digital Camera Basics

How Do Digital Cameras Work?

• DSLR: light comes through the lens and bounces off a mirror through a pentaprism into the eyepiece
  • To take a picture, mirror moves up to expose sensor
• Mirrorless: as the name suggests, no mirror in front of sensor
  • No optical viewfinder, only shows what the camera sees via live view on electronic display
  • To take a picture, no mirror has to move out of the way

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What About My Phone?

• Functions effectively identically to a mirrorless camera
• Much smaller sensor
• Most feature only one catch-all lens
• Great for convenience and portability, bad for control and options
• Some apps allow for manual controls, but options still limited

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Understanding Camera Controls

• It’s all about the light metering triangle
• Aperture, Shutter Speed, ISO
• By changing these 3 settings, you control your picture’s exposure
• Understanding the relationship of these 3 is pivotal to taking better photos

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Aperture

• A series of overlapping metal blades within the lens that adjust to let in more or less light
• Represented by f/ number, where smaller numbers mean a larger aperture
• Constant vs variable aperture lenses
• Most kit zoom lenses are variable aperture, much cheaper
• Larger aperture results in shallower depth of field (how much of the picture is in focus)

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Large Aperture vs Small Aperture Comparison

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Shutter Speed

• How long the sensor is exposed to light
  • Ranges generally between 1/4 s and 1/4000 s
• Slower shutter speeds can introduce motion blur
  • Good rule of thumb to avoid motion blur, shoot with a speed no slower than 1/ focal length of your lens
  • To stop action, shutter speeds of ~1/200 or faster are needed
• Large apertures allow for faster shutter speeds and slower shutter speeds allow for small apertures

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Fast vs Slow Shutter Speed Comparison

Image Credit: exposureguide.com

ISO

• Determines how sensitive to light the camera's sensor is
  • Values range typically between 100-6400, nowadays some cameras can go up to 12800 and beyond
• Lower ISO means less sensitive to light, resulting in longer shutter speeds and larger necessary apertures
  • also results in higher image quality and detail
• High ISO introduces grain/noise, makes images appear fuzzy

Image Credit: exposureguide.com

Why Does Any of This Matter?

• You can control all three of these settings yourself
• Strategic manipulation of these three settings based on what you’re shooting results in better overall pictures
  • Landscape vs Sports
  • Studio portraiture vs environmental portraiture
• Auto on cameras works ok for everything, but isn’t great for anything