f/8 and be there.
"Sunny 16" is (in addition to being the title of a Ben Folds (I think) EP (I think)) a photographer's rule of thumb for setting exposure values without metering. I suppose it's more accurate to say it's a mnemonic for the rule of thumb.
(Let's not diverge into a discussion of the origin of the term "rule of thumb.")
In any case, the rule of thumb is that if one sets one's shutter-speed to the inverse of the ISO rating of the film one is using (or the ISO the camera is set to, in a digital world), then in bright sunshine setting the aperture to f/16 (i.e., 1/16 the focal length of the lens in use) will yield an approximately correct exposure. In other words, if you film (or camera setting) is ISO100, set your shutter speed to 1/100 of a second, and as lighting conditions change, adjust your aperture. In bright sunshine, you want f/16. I'm a little vague beyond that, as my camera has through-the-lens (TTL) metering that I rely on almost exclusively, but there are a bunch of steps down from there.
I looked it up. The easy way to identify the lighting condition is by looking at shadows. Hard edges equals bright sunshine, and f/16. Soft shadows equals light overcast, and f/11. Barely visible shadows equals overcast, and f/8. No shadows equals heavy overcast, and f/5.6. You'll note that those numbers are full f-stop increments. Or maybe you won't ... the electronically controlled apertures of lenses for digital SLRs tend be be adjustable in increments of 1/3 or 1/2 stop, which has the effect (at least on me) of making it harder to learn what the full f-stops are. Perhaps writing this out will help me remember.
Anyway, knowing that rule, and understanding the way ISO, shutter speed, and aperture all trade off, and can be measured in exposure value (EV), means you can make shooting decisions. Suppose, for example, your camera is set to ISO 100. With your shutter set to 1/100 of a second, in slight overcast, you would want an aperture of f/11. But suppose you're shooting a moving subject, and you'd like to freeze that motion? Well, adjust your shutter speed to 1/200 of a second (-1 EV) and your aperture to f/8 (+1 EV), and you still have the same basic exposure. Or if you want more motion blur? Shutter speed to 1/50 of a second, and aperture to f/16.
But this post isn't entitled "Sunny 16," it's entitled "f/8 and be there."
"f/8 and be there" is (I'm told) a photojournalists saying that emphasizes the importance over being where the photo is happening and being ready to shoot over technical details. And it's something that I've found really helps my photography and, to some extent, my life. I'm a big old geek, with a big old geek's tendency to wallow in the technical details (see, for example, this post.) But thinking about every setting for every shot takes away not just from my ability to be ready to shoot and to be where I need to be, but from my ability to see the scene, to pick my subjects and frame my composition. (Please. I'm *not* claiming any great mastery at composition when I'm not focused on EV, just that I'm worse when I am.) And I think the lesson can be read as sort of zen message about life ... f/8 and BE THERE. Don't worry about the technical details to the detriment of being present and aware.
So, photographically rather than philosophically, this is what I do. I've got a sense of the noise-levels in the sensor of my 30D at various ISO settings, and I know I'm generally comfortable with the noise at ISO400. So I leave my camera set there almost all the time. I shoot "aperture priority," which means I tell the camera what aperture to use, and it combines that with the ISO setting to select a shutter speed that will yield an appropriate exposure.
When I'm shooting I generally pay attention to the shutter speed it's giving me for the first couple of shots, to make sure it's fast enough to avoid blurring effect from hand-shake (i.e., faster than the inverse of the effective focal length of the lens I'm using ... for an 85mm lens on a 1.8 crop factor body, faster than 1/150). If I need a faster shutter, I open up the aperture. But after those first couple, I just shoot ... I focus on what I'm seeing and not what setting I'm using. If I change venues or scenes, I'll re-set. And if I'm looking for specific effects, either compressed or expanded depth-of-field or motion-blur or -freezing, I'll adjust to get that effect.
One other thing that simplifies my decision process is the use of prime rather than zoom lenses. While the primary advantage of a prime lens is often the larger aperture, not having one more thing to worry about is kind of a benefit for me. When I do mount a zoom, I often find myself deciding if I want to be wide or long, racking the zoom all the way to the widest or longest focal length, and leaving it there. If I need to adjust framing a little, I tend to zoom with my feet, adjusting my distance from the subject. Maybe this is a weakness in my "game," but I'm young enough in this that anything that makes my decision-making simpler is a good thing.
I don't know if that applies to life as well as photography, or not.
(Let's not diverge into a discussion of the origin of the term "rule of thumb.")
In any case, the rule of thumb is that if one sets one's shutter-speed to the inverse of the ISO rating of the film one is using (or the ISO the camera is set to, in a digital world), then in bright sunshine setting the aperture to f/16 (i.e., 1/16 the focal length of the lens in use) will yield an approximately correct exposure. In other words, if you film (or camera setting) is ISO100, set your shutter speed to 1/100 of a second, and as lighting conditions change, adjust your aperture. In bright sunshine, you want f/16. I'm a little vague beyond that, as my camera has through-the-lens (TTL) metering that I rely on almost exclusively, but there are a bunch of steps down from there.
I looked it up. The easy way to identify the lighting condition is by looking at shadows. Hard edges equals bright sunshine, and f/16. Soft shadows equals light overcast, and f/11. Barely visible shadows equals overcast, and f/8. No shadows equals heavy overcast, and f/5.6. You'll note that those numbers are full f-stop increments. Or maybe you won't ... the electronically controlled apertures of lenses for digital SLRs tend be be adjustable in increments of 1/3 or 1/2 stop, which has the effect (at least on me) of making it harder to learn what the full f-stops are. Perhaps writing this out will help me remember.
Anyway, knowing that rule, and understanding the way ISO, shutter speed, and aperture all trade off, and can be measured in exposure value (EV), means you can make shooting decisions. Suppose, for example, your camera is set to ISO 100. With your shutter set to 1/100 of a second, in slight overcast, you would want an aperture of f/11. But suppose you're shooting a moving subject, and you'd like to freeze that motion? Well, adjust your shutter speed to 1/200 of a second (-1 EV) and your aperture to f/8 (+1 EV), and you still have the same basic exposure. Or if you want more motion blur? Shutter speed to 1/50 of a second, and aperture to f/16.
But this post isn't entitled "Sunny 16," it's entitled "f/8 and be there."
"f/8 and be there" is (I'm told) a photojournalists saying that emphasizes the importance over being where the photo is happening and being ready to shoot over technical details. And it's something that I've found really helps my photography and, to some extent, my life. I'm a big old geek, with a big old geek's tendency to wallow in the technical details (see, for example, this post.) But thinking about every setting for every shot takes away not just from my ability to be ready to shoot and to be where I need to be, but from my ability to see the scene, to pick my subjects and frame my composition. (Please. I'm *not* claiming any great mastery at composition when I'm not focused on EV, just that I'm worse when I am.) And I think the lesson can be read as sort of zen message about life ... f/8 and BE THERE. Don't worry about the technical details to the detriment of being present and aware.
So, photographically rather than philosophically, this is what I do. I've got a sense of the noise-levels in the sensor of my 30D at various ISO settings, and I know I'm generally comfortable with the noise at ISO400. So I leave my camera set there almost all the time. I shoot "aperture priority," which means I tell the camera what aperture to use, and it combines that with the ISO setting to select a shutter speed that will yield an appropriate exposure.
When I'm shooting I generally pay attention to the shutter speed it's giving me for the first couple of shots, to make sure it's fast enough to avoid blurring effect from hand-shake (i.e., faster than the inverse of the effective focal length of the lens I'm using ... for an 85mm lens on a 1.8 crop factor body, faster than 1/150). If I need a faster shutter, I open up the aperture. But after those first couple, I just shoot ... I focus on what I'm seeing and not what setting I'm using. If I change venues or scenes, I'll re-set. And if I'm looking for specific effects, either compressed or expanded depth-of-field or motion-blur or -freezing, I'll adjust to get that effect.
One other thing that simplifies my decision process is the use of prime rather than zoom lenses. While the primary advantage of a prime lens is often the larger aperture, not having one more thing to worry about is kind of a benefit for me. When I do mount a zoom, I often find myself deciding if I want to be wide or long, racking the zoom all the way to the widest or longest focal length, and leaving it there. If I need to adjust framing a little, I tend to zoom with my feet, adjusting my distance from the subject. Maybe this is a weakness in my "game," but I'm young enough in this that anything that makes my decision-making simpler is a good thing.
I don't know if that applies to life as well as photography, or not.