The Sunny 16 Rule or Sunny (f/16) Rule
The sunny 16 rule is a simple way to determine a good exposure for a photograph. On a clear, sunny day, when you are using an aperture of f/16, this rule recommends a shutter speed is the inverse of your ISO value.
To exemplify, imagine you’re photographing a landscape under clear, blue sky. You have dialed in f/16 as the aperture and are using an ISO of 100. Based on those settings, the Sunny 16 Rule recommends that the shutter speed be 1/100 seconds. Doing so will get you close to a well-exposed image.
The Sunny 16 rule works as a general guideline. It never was meant to be a precise way to find your optimal exposure – simply a guideline to help you down the right path.
Exposure Rules :
The Sunny 16 Rule is easy to remember because it’s used in the most common of weather situations. Though there are other rules also. They are not a guarantee, but will certainly help you to start in on the best exposure given the specific circumstances.
Observe Weather Technique:
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- Snowy/Sandy 22 Rule: If the sun is shining over a snowy landscape.
- Sunny 16 Rule: when photographing in an open field during a sunny day.
- Lightly Cloudy 11 Rule: when the sky is variable.
- Cloudy 8 Rule: cloudy weather, but not dark.
- Overcast 5.6 Rule: bad weather, may be rainy.
- Sunrise/Sunset 4 Rule: for typical sunset/sunset conditions.
Observe Shadows Technique (Forget the Weather):
The best way to guesstimate which rules best match, look at shadow hardness. Actual sky conditions can be misleading or confusing.
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- Snowy/Sandy 22 Rule: hard, deep shadows (snowy landscape, desert).
- Sunny 16 Rule: hard, deep shadows.
- Lightly Cloudy 11 Rule: soft shadows.
- Cloudy 8 Rule: very soft shadows.
- Heavy Overcast 5.6 Rule: With very soft shadows or no shadows at all.
- Sunrise/Sunset 4 Rule: very long shadows.
It is best to choose the lowest ISO setting on your camera which is normally ISO100 or ISO64 depending on camera model. To obtain good image quality (noise free) I would recommend not to go beyond ISO 640. Doing this will ensure your images will have the least amount of noise and you will have the widest aperture available to you. So, in all examples I have kept the ISO 200.
Have a look at the chart below to see how ISO remains constant. Note that with the Sunny 16 Rule, at f/16 and an ISO of 200, the shutter speed is 1/200. However, as you move down the list to the Slightly Overcast 11 Rule, the aperture changes by +1 stop(f/11), and the shutter speed changes by -1 stop (from 200 to 400), but the ISO remains the same to maintain overall exposure same. This pattern continues through each of the other shooting rules.
Assume that when you head out to take photos under heavily overcast sky, necessitating the use of the Overcast f/5.6 Rule. Just keep in mind Sunny 16 Rule, at f/16 and an ISO of 200 that the shutter speed is 1/200. So, in the Overcast 5.6 Rule, u have increased exposure by +4 stop using Aperture (from f/16 to f/5.6), in order to maintain overall exposure, now you have to decrease exposure by -4 stop using Shutter-speed (from 1/200 to 1/1600), as the ISO remains the same for better image quality (ISO 200 in this example).
In short, on a sunny day your settings would be like this: Aperture: f/16, Shutter Speed: 1/200 seconds, ISO: 200
But on a overcast day your settings would be like this: Aperture: f/5.6 (increased +4 stop compare to sunny 16), Shutter Speed: 1/1600 seconds (decreased +4 stop compare to sunny 16), ISO: 200
The Sunny 16 Rule is an easy way to start to get a good exposure, no matter the weather conditions. Rather than shoot via trial and error by checking for blinking highlights on the camera’s LCD until we have correct exposure. Some experienced photographer might argue that it is obsolete at this point, which is true. However, in my opinion, for photographers who are trying to expand their personal skill set and intuitive understanding of photography, the sunny 16 rule still has value. It also helps beginners understand the relationship between a scene’s appearance and the camera settings needed to capture it successfully. Practising with the sunny 16 rule is a great exercise to learn to read the available light – a must for any outdoor photographer. And you can start practising right away! Take a look out the window: is that sunny 16 weather or something else?
Now, it’s your turn. Tell me what settings (Aperture and Shutter Speed) do you prefer for the below image, when ISO is 640?
Hint: Put ISO 640 in Sunny 16 rule and then calculate
