What’s the Sunny 16 Rule in Photography?

by David Em

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The sunny 16 rule is also known as the sunny f/16 rule. It’s a method of determining the right camera settings for daylight exposure.

Sun with slightly cloudy blue skies.

What’s the sunny 16 rule?

The sunny 16 rule goes back to the film photography days, which was before cameras had built-in light meters.

With modern technology and cameras having a light meter, the sunny 16 rule may seem like something from the past that doesn’t matter anymore.

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While it’s true that the light meter replaced the method of determining the exposure, understanding the principles of metering and exposure will increase your knowledge.

The sunny 16 rule states that using an aperture of f/16, ISO of 100, and a shutter speed of 1/100 will give you good exposure during a sunny day with clear skies.

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At f/16, you can also use ISO 200, and make sure you increase your shutter speed to 1/200.

If you stick with f/16 and increase your ISO, just turn the ISO into a fraction, and that’s the shutter speed you should use.

This rule is a great starting point, however, you may not want to use an aperture of f/16 for all of your images.

If you increase your aperture by one stop, you’ll have to make your shutter speed faster by one stop.

For example, if you’re sticking with ISO 100 and changing your aperture to f/11, your shutter speed needs to be 1/200.

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Use it as a guideline

Consider this rule more of a guideline than a strict rule because there are exceptions and times that it won’t work.

The direction of light can cause an incorrect measurement of exposure, as will reflections.

You’ll find that it can lead to underexposure or overexposure. That’s why it’s a great starting point, and you must look at your light meter to make it perfect.


The sunny 16 rule is a useful method to help you measure the perfect exposure without using the light meter. If you want to expand your knowledge and skillset, practice this method before looking at the light meter.

Featured image courtesy of Unsplash.

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