What’s the correct exposure on a normal sunny day? There’s a formula to answer that, don’t you know? The correct answer is a shutter speed of 1/ISO at ƒ/16. So, with ISO 100 dialed in to the sensor, the correct exposure on a normal sunny day will be 1/100 sec. at ƒ/16. This handy rule of thumb is very helpful as it always gives you an idea of where to start while dialing in a manual exposure. The Sunny F/16 Rule is incredibly accurate as well.
But did you know that rule also corresponds to every other lighting scenario you might find outdoors? Here’s a handy guide to this, the Sunny F/16 Rule, that tells you what aperture to switch to as lighting situations change—from the brightest sunlight to the deepest dusk. In every case, the corresponding shutter speed will remain 1/ISO.
Bright Sun, Snow or Sand = ƒ/22
Normal Sunny Day = ƒ/16
Hazy/Lightly Cloudy = ƒ/11
Cloudy = ƒ/8
Overcast = ƒ/5.6
Sunset/Shade = ƒ/4
Dusk = ƒ/2.8
Part of the process of becoming a better photographer is taking control of your camera and its controls. Use this guide to know where to start dialing in manual exposures in any outdoor lighting situation. It will give you confidence and help you feel like you’re a master of manual exposure.
This technique has the added benefit of making you stop and think. With your camera on auto exposure, you may not be thinking very much about your shot. But, on manual, as you’re considering the exposure, you may find yourself thinking about composition and creative elements as well. Any technique that gets you to slow down a bit and think about your picture taking is okay by me, and will result in better images.