Sunny 16
Sunny 16 (Andreas Feininger called it "magic 16") is a rule-of-thumb guideline that says proper exposure on a sunny day is achieved with aperture set to f/16, combined with shutter speed set to the reciprocal of your film speed.
Exposure control by aperture setting:
Aperture should be wider in less bright light situations, i.e. half to full f-stop wider (f/13-f/11) for sunny but hazy, two f-stops (f/8) for clouds, and three f-stops wider (f/5.6) for strongly clouded sky, or even an f-stop smaller, i.e. f/22 for snow or white sands in bright sunshine. Of course small format cameras will produce diffraction unsharpness at such small aperture.
| Condition | Aperture for shutter speed set reciprocal to film speed |
| Bright sun | f16 |
| Hazy sun | f11 |
| Cloudy | f8 |
| strongly clouded, Overcast, Dull |
f5.6 |
Exposure control by shutter speed setting:
Of course a small aperture might be fine for landscape photos. So let it be set to f/16 and control exposure by shutter speed, setting it higher for bright snow, or lower for hazy or cloudy weather.
If we use a good ISO 100 film it has a fine color grain, allowing sharpest analog photographs. Thus a camera with a good lens will be prefered to shoot that film. But a good lens usually has its finest sharpness at an aperture wider than f/16! The third sample in the following table is given for a lens with optimal sharpness at aperture f/5.6
| Condition | Shutter speed for f/16 with film speed ISO 100 |
Shutter speed for f/16 with film speed ISO 400 |
Shutter speed for f/5.6 with film speed ISO 100 |
| Bright sun | 1/100 sec. | 1/400 sec. | 1/800 sec. |
| Hazy sun | 1/50 sec. | 1/200 sec. | 1/400 sec. |
| Cloudy | 1/25 sec. | 1/100 sec. | 1/200 sec. |
| strongly clouded, Overcast, Dull |
1/12.5 sec. | 1/50 sec. | 1/100 sec. |
For f/16 in bright sun use the closest match to the film speed's reciprocal value as shutter speed. For example 1/125 instead of 1/100 if speed scale doesn't offer 1/100, or 1/300 instead of 1/400 if the speed scale ends at 1/300.
Weather Symbols
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| Weather symbols on the shutter speed ring of a Cosmic Symbol. The aperture of this camera is preset depending on film speed. image by AWCam (Image rights) |
Sunny 16 is sometimes formalised onto a camera as weather symbols. The exposure controls are marked with sunny/cloudy (etc) symbols, mainly for aperture setting on cameras with single-speed-shutter.
