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The Ultimate Guide to Using the Sunny 16 Rule in Your Photography

As much as photography can be an experimental creative endeavor, there are several rules that have been in play since the medium’s creation. Between the Rule of Thirds for composition and exposure rules for landscapes, there is a lot to remember! One of the oldest rules is the Sunny 16 Rule, which has to do with exposing your image properly on a bright sunny day. 

Here is the Sunny 16 Rule explained! 

What is the Sunny 16 Rule? 

The Sunny 16 Rule is intended to be a quick photographer’s guide to some simple settings for a good exposure.

To refresh, exposure is the amount of light that reaches your camera. Too much light and your image will be too bright. Too little, and it’ll be too dark. To create exposure, you need your ISO level, your shutter speed, and our aperture. Exposure is a formula.

ISO + shutter speed + aperture = exposure. 

This rule aims to help you fill in the above formula the best. 

The Sunny 16 Rule states that when you are using an aperture of f/16 on a clear sunny day, you will also be using a shutter speed that is the same as your ISO value. For example, if your ISO is set to 100, you use a shutter speed of 1/100. If your ISO is 500, you use a shutter speed of 1/500, and so on. This is utilized often by landscape photographers and portrait photographers

That being said, keep in mind that not all are worthwhile, such as an ISO of 3200 shot with a shutter speed of 1/3200 (you’d never need such a high ISO on a bright sunny day). 

Implementing the Sunny 16 Rule 

Now, the rule is not always as straight as it sounds. You can use Sunny 16 to calculate the relationship between other aperture values and the shutter speed and ISO values, because it doesn’t always apply perfectly. 

With exposure being a formula, like any mathematical equation, if one variable is changed, the other variables are affected by the change. If you find that you don’t want to use an aperture of F/16, you can still use the Sunny 16 Rule to help you figure out how to fill in the exposure equation. 

If one factor goes up by one stop, another factor should go down by one stop. The most common examples are as such: 

If F/16 has no stop difference because that is your baseline, then say you want to change to F/11. This has a +1 stop. This can continue forth with F/8 having +2 stops, f/5.6 having +3 stops, f/4 having +4 stops, and f/2.8 having +5 stops. Those are the most common aperture settings that lenses tend to have. 

Likewise, if you leave the shutter at 1/200 at ISO 200 you have no stop difference, 1/400 at ISO 200 you have -1 stop, 1/800 at 200 ISO is -2 stops, 1/1600 at ISO 200 is -3 stops, 1/3200 at ISO 200 is -4 stops, and 1/6400 at ISO 200 is -5 stops. Phew, I think we got most of the settings covered there!

Sunny 16 Rule Variations 

Now, what if your location isn’t bright and sunny like the rule relies on? Here are the commonly known variations on the Sunny 16 Rule: 

  • Snowy conditions: f/22
  • Slightly overcast: f/11
  • Overcast: f/8
  • Heavy overcast: f/5.6
  • Open shade or sunset: f/4

How Does the Sunny 16 Rule Work with Modern Photography Equipment?

The Sunny 16 Rule originally came into play during the film era, when cameras were very simple. Some consider this rule a relic today because of the brand new functionality of DSLR and mirrorless cameras. 

The Sunny 16 Rule is based on the brightness of light only and not how that light is being reflected into the camera. You can use the Sunny 16 Rule to make sure that your exposure meter inside of the camera is not showing a bad reading. 

However, remember that the way your subject is facing the light can cause your picture to be too bright or too dark regardless of the Sunny 16 Rule. The color and reflectiveness of your subject can make a big difference in your exposure meter reading. 

There is a catch to the Sunny 16 Rule and a lot of newer lenses. The aperture width is determined by the lens build. Each lens has an optimal focus point, which means that at specific settings the lens has reached its full potential in regard to focus, clarity, and sharpness. 

For some lenses, narrowing the aperture to f/16, for example, doesn’t allow the lens to reach its optimal focus because the lens is best used at f/4, for example. Just keep this in mind if you’re finding a discrepancy in your lens when using it at different apertures! 


In conclusion, the Sunny 16 Rule is a great guide to use (especially for newer photographers) to ensure that your image isn’t too bright or too dark! But keep in mind that this rule is more of a suggestion and a guideline rather than a mandatory setting. 

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