What Is the Sunny 16 Rule

The Sunny 16 rule is one of the simplest and most reliable ways to expose film without a light meter. It helps you estimate the correct settings outdoors using only your eyes and basic camera controls.

The rule states:
On a sunny day, set your aperture to f/16 and your shutter speed to the reciprocal of your ISO.

For example, if you’re using ISO 100 film, your shutter speed should be 1/100s (or 1/125s if that’s your camera’s nearest setting).

This combination gives a well-balanced exposure in bright sunlight. From there, you can adjust the aperture or shutter speed as lighting conditions change.

Why Sunny 16 Works

The Sunny 16 rule is based on the fact that the sun’s brightness is consistent at sea level on clear days. By starting at f/16, you’re using an aperture small enough to control the intense light and maintain good depth of field.

Because film has wide latitude, small exposure variations are usually forgiven — making Sunny 16 a dependable method even without a meter.

Sunny 16 Base Exposure Formula

This table forms the foundation of manual exposure judgment. Once you understand these relationships, you can confidently shoot in most outdoor conditions without a meter.

Sunny 16 in Real Life

Let’s explore how Sunny 16 works across different outdoor lighting scenarios with real-world examples.

1. Midday Beach Scene

Bright sand and water reflect a lot of light, often tricking meters into underexposing.

Start with f/16 at 1/100s for ISO 100 film.
To protect highlights in very bright conditions, close down slightly to f/22.

Result: Perfectly detailed sky, natural skin tones, and bright but not blown-out sand.

2. Portrait in Open Shade

When your subject stands under a tree or near a building, light levels drop by about two stops compared to direct sun.

Open up your aperture to f/5.6 while keeping shutter speed constant.

Example: ISO 400 film → f/5.6 at 1/400s.

Result: Balanced skin tones and softer contrast, ideal for flattering portraits.

3. City Street on a Bright Afternoon

Urban environments include mixed lighting — sunlit areas and deep shadows.

Start with f/11 at 1/200s for ISO 200 film.
If most of your frame is in shadow, open up to f/8.

Result: Well-exposed subjects even in high-contrast conditions.

4. Snow or Beach Under Full Sun

Snow and sand reflect enormous amounts of light, often leading to underexposed results if you rely on automatic meters.

For these high-reflective scenes, stop down one additional stop from Sunny 16 — use f/22.

Example: ISO 100 film → 1/100s at f/22.

Result: Preserved detail in bright highlights and crisp, clean whites.

5. Cloudy or Overcast Day

Overcast skies scatter light evenly, creating a softer look with less contrast.

Switch to f/8 for light overcast or f/5.6 for heavy clouds.

Example: ISO 200 film → 1/200s at f/8.

Result: Evenly lit images with gentle tones and no harsh shadows.

6. Golden Hour or Sunset

During late afternoon or sunset, light intensity drops quickly but remains directional and warm.

Open up your aperture by two or three stops — try f/5.6 or f/4.
You can also slow down your shutter speed if shooting handheld light allows.

Example: ISO 400 film → 1/250s at f/4.

Result: Warm highlights and soft contrast that retain the film’s characteristic glow.

Adapting Sunny 16 to ISO Changes

The rule adjusts easily with film speed.
Use the reciprocal relationship between ISO and shutter speed as your baseline:

If your camera doesn’t have those exact shutter speeds, use the nearest setting (for example, 1/500s for ISO 400 film).

Sunny 16 Cheat Sheet for Travel

Here’s a quick reference for when you’re shooting on the go without a meter:

This cheat sheet fits perfectly on a small card in your camera bag and works reliably across most film types.

Combining Sunny 16 with the Exposure Triangle

Once you know your base exposure, you can creatively adjust it using the exposure triangle:

• Use slower shutter speeds to brighten or capture motion.

• Use wider apertures for shallow depth of field.

• Keep ISO constant based on your film type.

For example, if your Sunny 16 reading is 1/125s at f/16 and you want a shallow depth of field, open to f/4 and increase shutter speed by four stops to 1/2000s.

Sunny 16 and Film Latitude

Film’s wide latitude makes Sunny 16 even more forgiving.
Color negative film can tolerate two or three stops of overexposure without losing highlight detail.

If uncertain, slightly overexpose rather than underexpose — especially when using film like Kodak Portra 400 or Fujifilm Superia 200.
This ensures your shadows stay rich and printable.

When Sunny 16 Does Not Apply

While versatile, Sunny 16 isn’t suited for every situation. Avoid relying solely on it when:

• Shooting indoors or at night

• Working under artificial light with unknown color temperature

• Photographing fast-changing light such as under moving clouds

In these cases, use a light meter app or handheld meter for accuracy.

FAQs About the Sunny 16 Rule

Does Sunny 16 work for digital cameras
Yes, but it’s most useful for film because of film’s broad exposure latitude. Digital sensors may clip highlights more easily.

What if my camera doesn’t have 1/100s or 1/200s shutter speeds
Use the nearest setting — for ISO 100, 1/125s is perfectly fine.

Can I use Sunny 16 for black and white film
Absolutely. Black and white stocks like Ilford HP5 or Kodak Tri-X respond beautifully with slight overexposure.

Is Sunny 16 accurate in different countries or altitudes
Yes, it works anywhere near sea level in bright daylight. At high altitudes or near the equator, stop down half a stop.

What about mixed lighting (sun and shade)
Meter for the dominant area — or split the difference between sun and shadow values.

Is Sunny 16 better than guessing exposure
Yes, it’s based on consistent light intensity and is accurate to within one stop for most conditions.

Conclusion: Confidence Without a Meter

The Sunny 16 rule proves that great photography doesn’t depend on gadgets — it depends on understanding light.

By memorizing just a few adjustments, you can confidently expose film in nearly any outdoor condition. Whether you’re exploring cities, mountains, or coastlines, Sunny 16 keeps your shooting simple, intuitive, and beautifully analog.

Print out the cheat sheet, trust your eyes, and let film’s natural latitude do the rest — every frame will teach you more about how light truly behaves.