In life, we are sometimes met with certain inalienable truths: water will always flow downhill, there will always be an unhappy baby on your flight, and the milkshake machine at your favorite fast-food restaurant will always be broken when you need it the most.
There are also some self-evident truths that we must accept regarding photography. For instance, one day, you will need to set your own exposure manually. And if you’ve been shooting exclusively in Auto mode, Aperture Priority mode, or Shutter Priority mode, that can be an enormous challenge.
Don’t get too discouraged, though! Shooting in Manual mode isn’t exactly a walk in the park, but there are powerful shortcuts you can use to make your work a whole lot easier. I’m about to show you one of the easiest and most long-standing methods for calculating exposures, and using it will help you almost always get a good baseline exposure when shooting your camera in full manual mode. (Yes, really!)
It’s called the Sunny 16 rule, and it’s about to be your best friend.
If you’ve been doing photography for a while, you may very well have heard of Sunny 16. But you likely never fully understood how simple it is to implement this handy little formula to fit the shooting situation, and how incredibly effective it can be.
Let’s dive right in!
What is the Sunny 16 rule?
The Sunny 16 rule is simple to understand. It relies on the relationships between the three key elements of exposure: ISO, aperture, and shutter speed.
Sunny 16 had its roots in film photography, and it was used to help photographers figure out their exposure when a light meter wasn’t available. But it works perfectly well with digital photography, too. In fact, since we have the added convenience of on-the-fly ISO adjustments with our digital cameras, the Sunny 16 rule is more useful than ever before!
As you might have guessed, the Sunny 16 Rule begins with bright sunlight and setting the aperture to (drum roll, please!) f/16.
Note: Bright sunlight refers to unobstructed sunlight on a cloudless day; think noon with a clear sky.
Once you’ve set your aperture to f/16, you can dial in your shutter speed based on the ISO you happen to be using at the time. To calculate your shutter speed based on Sunny 16, just put a “1” over your ISO.
Keep in mind that some cameras measure exposure in full, half, or third stops, so your shutter speed might not be exactly the same as 1 over your ISO. For example, if your camera measures exposure in half-stop increments, when shooting at ISO 400, then your exposure would be f/16 at 1/500s (since no 1/400s shutter speed is available). At ISO 100, your settings would be f/16 at 1/125s. For ISO 800, it would be 1/1000s.
And that really is the core of the Sunny 16 rule: On a bright, cloudless day, you’ll get a good exposure by dialing in an f/16 aperture, your ISO of choice, and a shutter speed of 1 over the ISO setting.
(You might be wondering how you should pick your ISO. In general, it’s a good idea to dial in your camera’s base ISO value, then leave the setting alone unless you absolutely need to raise it. There’s not much need to adjust the ISO as you can vary your exposure using the aperture and shutter speed settings. The exception is when the scene requires a higher ISO; more on this in just a bit!)
Why the Sunny 16 rule is so useful
The Sunny 16 rule is helpful for one huge reason: it gives you a usable exposure setting based on what will likely be the brightest light you will encounter (the sun!).
Once you know what your shutter speed will be at a given ISO and f/16 in bright sunlight, you can basically estimate any exposure for darker environments, as well as any exposure based on different f-stop, shutter speed, or ISO choices. This is because the f-stop, shutter speed, and ISO are all connected. You can adjust each relative to the other so that you can control your exposures based on the needs of a particular scene.
Perhaps one of the best things about working with the Sunny 16 rule is that it’s a great way to teach yourself to read light. Plus, it’ll help you adjust your exposure based on the creative requirements for your photo.
Let’s look at some considerations to take into account when you need a little more control over your photographs using the Sunny 16 concept.
How to modify the Sunny 16 rule for different shooting scenarios
Years ago, when I first learned the Sunny 16 rule, my first thought was “That’s great, but what if I don’t want to photograph at f/16? Maybe I want a shallower depth of field than what f/16 can produce.”
It’s a common response, and a good one, too. There are other related questions, such as: what if the indicated ISO-based shutter speed isn’t fast enough or slow enough for your subject? Or what if I’m not always photographing in blazingly bright sunlight (which is ironically not ideal for most photography!)?
The good news is that the Sunny 16 rule is incredibly flexible.
Remember, the Sunny 16 rule does nothing more than eliminate variables in your exposure to produce a baseline camera setting for a particular type of light. You can then manipulate and modify this setting given your specific needs and lighting conditions.
For example, let’s say you’re shooting a subject that requires a shallow depth of field, like a portrait or still life, and let’s assume you’re shooting in bright sunlight. At ISO 100, your resulting Sunny 16 exposure would be f/16 at 1/125s. For reference, here’s a sample photo I shot using those exact settings in direct afternoon sunlight:
Needless to say, if I were to then open my aperture to f/2.8 (five full stops wider) in order to better blur the background, the resulting image would be completely overexposed. Here’s how it might look:
So how do we remedy this problem so you can capture your shallow depth-of-field photo? Since we are working from the Sunny 16 rule, all we have to do is apply some basic photographic principles to set our exposure based on our new, wider aperture.
Specifically, since we opened up our aperture by five stops, we simply need to increase our shutter speed by five stops to compensate!
So if the initial shutter speed were 1/125s at f/16, the new adjusted shutter speed setting at f/2.8 would be 1/4000s. Here is the same scene as above, shot with the modified settings:
You can use the same approach to photograph fast-moving subjects. If you’re experiencing unwanted subject motion at 1/125s at f/16, you can boost your shutter speed to 1/500s, then compensate by widening the aperture. In this case, 1/500s is two full stops faster than 1/125s, so you would open your aperture by two stops from f/16 to f/8 while keeping the ISO constant.
Some adjusted Sunny 16 baseline exposures
But what if you’re photographing in lighting situations other than bright sun? Here’s a quick (but by no means definitive!) list of baseline aperture adjustments derived from the Sunny 16 rule. I’ve listed Sunny 16 at the top as a baseline exposure. To adjust your exposures as the light gets dimmer, all you need to do is change your aperture.
- Direct bright sunlight with harsh shadows: f/16 at 1/125s and ISO 100
- Indirect bright sun with soft shadows (shade/cloudy): f/11 at 1/125s and ISO 100
- Overcast skies with little to no shadow: f/8 at 1/125s and ISO 100
- Dusk/morning light: f/4 at 1/125s and ISO 100
I also want to address the elephant in the room: Why not just bump up the ISO?
In fact, this is a great option! You can adjust your ISO settings to compensate for more or less light in the scene, and modern cameras are becoming better and better at reducing high-ISO digital noise. The Sunny 16 rule was based on the fact that most film cameras are limited to the ISO of the film used. But if you would prefer to modify your exposure by adjusting the ISO instead of changing the aperture, go ahead!
Nail your exposures with Sunny 16!
The concept of Sunny 16 gives us digital shooters a way to capture accurate exposures (or near-accurate exposures) without constantly checking our images after each shot. And it works even when dealing with tricky subjects (such as dark rocks or white snow).
Of course, as with most things, the Sunny 16 rule isn’t a true “rule” in the sense that you must follow it to the letter. Instead, it is a rule in that it spells out a relationship between exposure and lighting conditions. Put another way, it allows us to relate the luminance of available light to our camera settings to achieve predictable and reproducible results.
Sunny 16 is also a great learning tool to help us understand the nature and measurement of light. And it’s extremely versatile once you commit a few basic principles of exposure to memory. I, for one, feel as if I don’t use Sunny 16 enough in my work. I think that is about to change.
Now over to you:
Do you practice the Sunny 16 rule? How has it affected your shooting? Let us know in the comments below!
