Exposure / Metering
Exposure Value (EV) & Sunny 16 Helper
Compute Exposure Value from ISO, aperture, and shutter speed, dial in the Sunny 16 rule for any lighting condition, and see equivalent exposure pairs and ND-adjusted shutter speeds live as you type.
Exposure Settings
Sunny 16 Presets
Click a lighting condition to set aperture and shutter (≈1/ISO) automatically.
Bright sun f/16 · Slight overcast f/11 · Overcast f/8 · Heavy overcast f/5.6 · Open shade / sunset f/4. Shutter ≈ 1/ISO at each.
Results
Equivalent Exposures (same EV)
How this works: Exposure Value is calculated as EV = log₂(N²⁄t) from your aperture and shutter, then normalized to ISO 100 by subtracting log₂(ISO⁄100) so readings at different ISOs are comparable. The Sunny 16 rule assumes shutter ≈ 1/ISO in bright sun at f/16, with the aperture opening up as light falls off. ND filters push your shutter speed longer by 2 stops for every stop of density, without changing exposure.
Understanding Exposure Value and the Sunny 16 Rule
Exposure Value (EV) collapses three camera settings — aperture, shutter speed, and ISO — into a single number that describes how much light reaches your sensor. Two very different combinations, like f/8 at 1/500 and f/16 at 1/125, can produce the exact same EV, and therefore the exact same exposure. Once you understand EV, you can move between settings freely without losing track of brightness.
The EV / Sunny 16 Helper calculates your Exposure Value from any aperture, shutter speed, and ISO combination, normalizes it to the ISO 100 standard so readings are comparable across cameras, and builds a full ladder of equivalent exposures at your chosen stop increment. It also bakes in the classic Sunny 16 rule, so you can set a correct daylight exposure without a meter at all.
How the EV Formula Works
Exposure Value is defined as EV = log₂(N²⁄t), where N is your f-number and t is your shutter speed in seconds. Because ISO isn’t part of that formula, the same aperture and shutter give a different practical exposure at ISO 100 than at ISO 1600 — the sensor is simply more sensitive. To make EV comparable across ISOs, the tool subtracts log₂(ISO⁄100) to produce a standardized EV100 value, which is what you’ll usually see quoted in exposure tables and light meter charts.
The Sunny 16 Rule
On a bright, sunny day with your aperture set to f/16, the correct shutter speed is approximately 1/ISO seconds. As the light drops off — through slight overcast, full overcast, heavy cloud, and open shade — the aperture opens up roughly a stop at a time down to about f/4, while the shutter speed stays pinned near 1/ISO. Click any of the preset chips in the tool to drop that condition’s aperture straight into the calculator using your current ISO.
ND Filters and Equivalent Exposures
Add an ND filter’s strength in stops and the tool shows the shutter speed you’d need at the same aperture and ISO to hold exposure steady — useful for pulling shutter speeds down into cinematic or long-exposure territory in bright conditions. The equivalent exposures table below the results does the same job across a full range of apertures: pick any row and you’ll land on the identical EV, just traded between depth of field and motion blur.
This tool is especially useful for:
- Photographers without a meter who need a reliable daylight starting point.
- Matching exposure across multiple cameras or lenses with different native ISO ranges.
- Planning ND filter strength for long exposures or cinematic shutter angles in daylight.
- HDR and bracketing workflows where you need precise stop offsets from a base exposure.