Understanding the exposure triangle of shutter speed, aperture, and ISO is one of the first steps in learning photography. To help people wrap their heads around the concept, photographer Tony Catalano has created the Interactive Exposure Tool, an online tool for experimenting with how changing camera settings affects the resulting photo of a scene.
As you can see from the screenshot above, the page is extremely simple and straightforward. On the left side is a low-light scenario showing a spinning fan and Christmas lights in the background. On the right side are three sliders for shutter speed, aperture, and ISO.
Drag the sliders to see how the resulting photo changes. Change the mode from Manual to Shutter Speed Priority or Aperture Priority to see how those specific settings alter the image. Use f/1.8 (a large aperture) to throw the background out of the focus, or use f/22 (a small aperture) to have your foreground and background both in focus:
A fast shutter speed will freeze the spinning fan, allowing you to clearly see the individual blades. A slow shutter speed will cause it to be captured as a blur:
You’ll also notice that your shot becomes more or less noisy depending on what you set ISO to.
Head on over to the Interactive Exposure Tool if you’d like to play around with it yourself — it’s both free and mobile friendly. It’s also great for sharing with someone who’s just starting out in photography.