Sunny 16 Rule Calculator
Enter your ISO to get the Sunny 16 shutter speed at f/16, then pick a lighting preset or aperture for the equivalent exposure in less light.
How to use the Sunny 16 calculator
- Enter your ISO. The base shutter at f/16 is one over the ISO.
- Pick a lighting preset or type an aperture f-number.
- Read the equivalent shutter speed that keeps the same exposure.
Examples
Bright sun at ISO 100
ISO 100, f/16
1/100 s
Open up to f/8
ISO 100, f/8
1/400 s (two stops faster)
Frequently asked questions
What is the Sunny 16 rule?
On a bright sunny day, a correct exposure at f/16 uses a shutter speed of one over the ISO. At ISO 100 that is about 1/100 second, at ISO 200 about 1/200 second.
How do I adjust for clouds or shade?
Open the aperture as light drops: f/11 for slight overcast, f/8 for overcast, f/5.6 for heavy overcast and f/4 for open shade, keeping the same shutter speed family.
How does changing aperture change the shutter?
Light scales with one over the f-number squared, so the equivalent shutter is the base shutter times the f-number over 16, squared. Opening to f/8 makes the shutter four times faster.
Why use Sunny 16 if my camera has a meter?
It is a fast sanity check and a fallback when a meter is fooled by snow, backlight or a bright sky. It also builds an intuition for how stops trade off.
Does Sunny 16 work at any ISO?
Yes. The rule scales with ISO. At ISO 400 the base shutter at f/16 is about 1/400 second, and the preset apertures behave the same way relative to f/16.
Related tools
Exposure Value Calculator
Calculate exposure value from aperture and shutter speed, adjusted for ISO. Get EV at ISO 100 and at your ISO to compare exposures by stops. Free and instant.
F-Stop Calculator
Calculate the stops of light between two f-stops and the light ratio. See which aperture is brighter and by how much. Free and instant.
Flash Guide Number Calculator
Calculate flash guide number, aperture or distance from the GN = aperture x distance rule, with ISO scaling. Solve any one from the other two. Free.
Aperture Area Calculator
Calculate the physical aperture diameter and area from focal length and f-number. See how area scales with the square of the f-stop. Free and instant.
Crop Factor Calculator
Find your sensor crop factor versus full frame and the 35mm-equivalent focal length and f-number. Works for APS-C, Micro 4/3 and any sensor size. Free.
Depth of Field Calculator
Calculate depth of field from focal length, aperture and focus distance. Get the near limit, far limit, total DoF and hyperfocal distance. Free and instant.