The Sunny 16 Exposure Cheat Sheet

The Sunny 16 Rule is one of the most famous and fundamental concepts in photography, especially for those shooting film or using fully manual settings without a light meter.1

It's essentially a mnemonic or a reliable guideline for estimating correct exposure in bright sunlight.

What the Sunny 16 Rule States

The rule is very simple and provides a reliable baseline for the Exposure Triangle (Aperture, Shutter Speed, and ISO) when shooting outdoors in daylight.2

The Rule

On a bright, sunny day, set your camera's aperture to f/16, and your shutter speed should be the closest corresponding fraction of your ISO speed.3

How to Apply It

1. Aperture: Always set to f/16.4

2. ISO: Choose your film speed or digital ISO (e.g., ISO 100, 200, 400).

3. Shutter Speed: Use the reciprocal of your ISO value.

ISO SettingApertureShutter SpeedISO 100f/161/100th of a secondISO 200f/161/200th of a secondISO 400f/161/400th of a second

Why is it Useful?

1. Estimating without a Meter: It allows you to take pictures when your camera's light meter fails, or if you're using a simple film camera without a meter.5

2. Fast Action: It helps you quickly dial in a starting exposure without wasting time fiddling with a meter reading.6

3. Depth of Field: Because f/16 is a narrow aperture, it provides excellent depth of field, meaning most things from the foreground to the background will be sharp, which is ideal for landscapes.

4. Foundation for Adjustment: Once you have the f/16 baseline, you can easily adjust for creative effects using the Exposure Triangle principles:

   • If you want a shallower depth of field (like f/8), you open the aperture by two stops. To keep the exposure correct, you must then speed up your shutter speed by two stops (e.g., from 1/100s to 1/400s).

Adjusting for Different Light Conditions

The Sunny 16 rule works best for direct, hard sunlight.7 The cheat sheet I sent you accounts for these variations, but the general rules of thumb are:

ConditionAperture at ISO 100 (keeping Shutter Speed at 1/100s)Sun on Sand/Snow (Extra Bright)f/22 (1 stop brighter)Bright Sun (Hard Shadows)f/16 (The Baseline)Hazy Sun (Soft Shadows)f/11 (1 stop darker)Overcast (No Shadows)f/8 (2 stops darker)Heavy Overcast/Open Shadef/5.6 (3 stops darker)

Does that make sense? It's a surprisingly simple rule that can save a shoot! Now you know exactly how the calculator in the HTML file works!

Understanding the Magic of the Sunny 16 Rule

The Sunny 16 Rule is a foundational rule-of-thumb in photography, especially beloved by film shooters and those who prefer shooting fully manual without relying on a camera's internal light meter. It allows you to quickly estimate the correct exposure settings based purely on ambient light conditions.

The Core Principle

The rule is built on a simple premise: on a bright, sunny day, set your aperture to f/16, and your shutter speed should be the closest reciprocal of your film's ISO speed.

Shutter Speed=ISO1​atf/16

Examples:

• ISO 100 Film: Set Shutter Speed to 1001​ (usually 1251​ or 1001​ second) at f/16.

• ISO 400 Film: Set Shutter Speed to 4001​ (usually 5001​ second) at f/16.

Why Use the Sunny 16 Tool?

This tool does the mental math for you! Instead of calculating the shutter speed for the base f/16 and then having to adjust the shutter speed by 2 or 3 stops to compensate for, say, an f/5.6 aperture, our calculator instantly provides the final, correct settings for any combination of ISO and light condition.

It’s perfect for:

1. Film Photography: When you don't have a reliable meter or are shooting with a vintage camera.

2. Quick Metering: When the light is constant and you need a fast, accurate baseline before taking a reading with a dedicated meter.

3. Manual Shooting: Training your eye to understand light intensity and its direct relationship to exposure values (EV).

Note: The Sunny 16 Rule is an estimation. Light conditions are subjective (what's "Overcast" to one person might be "Heavy Overcast" to another). Always review your results!