Understanding and Using ISO to Take Great Pictures


Today, digital cameras made taking pictures inexpensive. To get the best images, you need the correct setting, and a splendid way to learn is to experiment. You’ll discover how changing the ISO, shutter speed and angle of the shot, will give you the best outcome.

Professionals do the same thing. Once they’ve set-up an important shot, they’ll take dozens of the same shot. This ensures the best possible combination of ISO and shutter speed.

Concerning ISO

For a technical foundation to photography, understand what ISO is and how it works. Three technical pillars are involved with photography:

  • ISO
  • Aperture
  • Shutter speed

1. What exactly is ISO?

This is your camera’s level of sensitivity to light, which gathers it and turns into usable images. It’s the most expensive part of any camera.


  • The lower the ISO number, the less sensitive it is.
  • The higher ISO number means the more sensitive it is to light.

This can be easily adjusted via an internal menu (different with each camera) and in turn controls an ‘image sensor’. While this sounds like a perfect solution, there is a drawback; as the ISO increases, so does the noise (grain) in the picture.

Experiment with different ISO settings for immediate feedback. Also use your camera’s manual for an excellent overview of how everything works.

Camera Settings

The settings you use will also affect the end result. Do these:

  • Set your camera on the highest resolution and highest JPEG compression.
  • Adjust as you gain experience.

Each camera has a ‘Basic ISO,’ meaning this is the lowest number an ‘image sensor’ can use to:

  • Gather light.
  • Produce a quality image, without adding noise.

Newer cameras have a base number between 100 and 200, which varies depending on manufacturing costs incurred. For most purposes, stick with the base ISO number, then adjust as you experience level increases.

How ISO Works

You’ll find an ISO sequence like 100, 200, 400, 800, 1600, 3200, 6400. This represents a geometric x2. It might be confusing, but just understand that each double numbering increases sensitivity by 2, thus:

  • 200 is twice as sensitive as ISO 100.
  • ISO 400 is four times as sensitive (meaning it needs four times less time to capture the same amount of light for an image).
  • When in doubt, use auto-exposure and auto focus. Avoid auto-ISO for anything other than low-light action shots. Try your camera’s lowest ISO setting before venturing higher, since this will generate more noise.

ISO Speed Examples:

• ISO 100 – 1 second

• ISO 200 – 1/2 of a second

• ISO 400 – 1/4 of a second

• ISO 800 – 1/8 of a second

• ISO 1600 – 1/16 of a second

• ISO 3200 – 1/32 of a second

This may all be confusing but take heart. It only means you lack a bit of experience. Get out there, have fun, take pictures and learn from the images you capture.