7. Use the aperture to control exposure
If you're new to manual mode, you might feel overwhelmed by all the settings—ISO, shutter speed, and aperture—and not know where to start. Here's what you should do: Set the ISO at 100 (or its lowest value), choose a shutter speed of 2 seconds, and an aperture of f/8. Then take some pictures, varying the aperture setting after reviewing the results. The smaller the f-number you dial in, the brighter your fireworks will be. If your photos are getting overexposed, increase the f-number. If the photos are too dark, shoot at a smaller f-number. This scene is the result of a 4-second exposure at f/8.