Interactive f-stop Calculator
Use this tool to calculate a new aperture after changing by any number of stops. You can also add shutter speed and ISO to get equivalent exposure settings.
What is an f-stop?
An f-stop (or f-number) is a way to describe your lens aperture, which controls how much light enters the camera. Common values include f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, and so on. Smaller f-numbers mean a wider opening and more light. Larger f-numbers mean a narrower opening and less light.
Each full stop changes light by a factor of two. For example, moving from f/4 to f/5.6 cuts light in half, while moving from f/4 to f/2.8 doubles the light. This is why f-stop calculations matter whenever you adjust exposure manually.
How this f-stop calculator works
The calculator uses the standard exposure relationship for aperture and stops:
If you include a shutter speed and ISO, the calculator also gives equivalent values needed to keep brightness the same after your aperture change.
- Equivalent shutter: new shutter = old shutter × 2^(stops)
- Equivalent ISO: new ISO = old ISO × 2^(stops)
Standard f-stop chart
Use this quick reference for full-stop aperture values:
| More Light | Middle Range | Less Light |
|---|---|---|
| f/1.0 | f/4 | f/16 |
| f/1.4 | f/5.6 | f/22 |
| f/2 | f/8 | f/32 |
| f/2.8 | f/11 | f/45 |
Practical examples
Example 1: Portrait in soft light
You start at f/4 and want a shallower depth of field, so you open up by 2 stops. Your new aperture becomes f/2. If shutter speed was 1/200, you can compensate to 1/800 to keep exposure consistent.
Example 2: Landscape for more sharpness
You shoot at f/5.6 and decide to stop down by 1 stop to f/8 for better depth of field. To keep brightness unchanged, your shutter speed should become twice as long (for example, 1/250 to 1/125) or ISO should double (100 to 200).
Example 3: Fast action indoors
If your shutter is already as fast as possible, opening from f/4 to f/2.8 gives one extra stop of light. That can let you reduce ISO noise or freeze motion better.
Aperture, depth of field, and image quality
- Wide aperture (f/1.4–f/2.8): brighter image, blurry background, stronger subject isolation.
- Mid aperture (f/4–f/8): balanced sharpness and depth of field for general shooting.
- Narrow aperture (f/11+): deeper focus range, useful for landscapes and architecture.
Remember that very narrow settings may introduce diffraction softness on some cameras, while very wide settings can reduce edge sharpness depending on lens design.
Common f-stop mistakes to avoid
- Confusing a larger f-number with a larger opening (it is actually smaller).
- Changing aperture without balancing shutter speed or ISO.
- Ignoring depth of field when selecting aperture.
- Using only full stops and forgetting that modern cameras support 1/3-stop adjustments.
Quick FAQ
Is one stop always double or half the light?
Yes. One full stop is always a 2× light change, no matter which exposure setting you adjust.
Can I enter decimal stop values?
Absolutely. You can enter values like 0.3, 0.7, or 1.5 to represent third-stop and half-stop style adjustments.
What shutter formats are accepted?
You can enter fractional form (like 1/125) or decimal seconds (like 0.008).
Use the calculator above whenever you need quick, reliable aperture conversions and equivalent exposure settings for photography.