This week, we’ll wrap up our series on shooting modes with a very easy way to shoot in manual, called “Sunny 16.” Some photographers have even gone so far as to say that using this method, you can replace your light meter (which I think is too optimistic by half). What it does instead, I think, is eliminate some of the guesswork from choosing your exposure settings.
Your first step is to choose your ISO. If you’re shooting in daylight on a clear day, you can easily get away with an ISO of 100 or 200. ISO 400 is good for days that are a bit overcast, or when your light is unpredictable. ISO numbers of 800 and above should be used either when your lighting is awful, or when you need to use a higher shutter speed in conjunction with a stopped-down aperture (think sports and event photography). As previously discussed, try your camera out at various ISO settings when the results don’t matter, so that you know what tradeoffs come with higher ISOs, and how well your camera does, or does not, handle noise and loss of detail in those higher reaches.
Having chosen your ISO, leave it on that number and forget about it. You will now choose your shutter speed, which will be the reciprocal of your ISO. So, in other words, if your ISO is 200, your shutter speed will be 1/200.* You may now also forget your shutter speed.
All that leaves is your aperture. In broad daylight, under normal conditions, f/16 coupled with a “matched” ISO and shutter speed will give you a correct exposure. If your exposure is off, one of two things are wrong. The first potential cause can be the camera itself; some cameras will simply under- or over-expose slightly, more or less by default. You have the option of either correcting this via exposure compensation, or by changing your aperture.
The other possibility here is that the camera’s right, and there’s either more, or less, light in the scene than you thought. Remember, just because we’ve set our ISO and shutter speed and then effectively set them aside, that doesn’t mean it’s a good idea to ignore what the camera’s light meter is telling us. Check the metering, and make adjustments accordingly.
Of course, the light doesn’t always do what we’d like. On different days (or even in different locations on the same day), you may find that f/16 isn’t quite cutting it. There are a few rules of thumb, therefore, for dealing with lighting situations that fall outside the “standard.” If f/16 is our baseline, then we may need to step up, or down, depending on lighting conditions, like so:
- f/22 (down one stop) for beach scenes and snow
- f/11 (up one stop) for weak sunlight, or dawn/dusk light
- f/8 (up two stops) if it’s overcast
- f/5.6 (up three stops) if it’s seriously overcast, or if your subject is in shadow
- f/4 (up four stops) for sunset or open shade
If you’re not altogether sure what kind of light you’re dealing with, look for shadows. The sharper and more detailed the shadow, the higher the f/number you’ll need. If shadows are indistinct or nonexistent, you’ll need more light, and a wider aperture.
Bear in mind, as well, that you may not always need a full stop’s worth of light in one direction or another. Sometimes going from f/16 directly to f/11 means going from a shot that’s slightly underexposed to one that’s washed out; use your meter and your common sense. With that caveat in mind, however, this can be a great way to demystify shooting in manual, and taking more control over your camera and the exposures it gives you. Have fun with it!
*Shutter speed settings vary by camera; some cameras won’t have a shutter speed that precisely matches the ISO you’ve chosen. If that’s the case, choose the closest applicable shutter speed by rounding up. Example: if your ISO is 100, your shutter speed may well be 1/125.