An f-stop chart lists the aperture numbers on your lens in order, and each full step lets in half as much light as the one before. The standard full-stop series is f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22 and f/32. Small numbers mean a wide opening and shallow depth of field, and large numbers mean a narrow opening and more of the scene in focus.
The Full-Stop Chart
| F-stop | Opening | Typical use |
|---|---|---|
| f/1.4 | Very wide | Dim rooms, strong background blur |
| f/2 | Wide | Portraits, low light |
| f/2.8 | Wide | Events, indoor sports |
| f/4 | Medium | Group portraits, travel |
| f/5.6 | Medium | General daytime shooting |
| f/8 | Narrow | Landscapes, street scenes |
| f/11 | Narrow | Landscapes, architecture |
| f/16 | Very narrow | Deep focus, sunburst effects |
| f/22 | Very narrow | Special cases, long exposures |
Why the Numbers Look Odd
The f-number is the focal length divided by the opening diameter. Each full stop multiplies the number by about 1.4, which is the square root of two, because light depends on the area of the opening. Doubling the area needs a diameter increase of 1.4 times. That is why the series rounds to 1.4, 2, 2.8, 4 and so on.
Third-Stop Values
Most cameras adjust in thirds of a stop. Between f/2 and f/2.8 you will see f/2.2 and f/2.5. Between f/4 and f/5.6 you will see f/4.5 and f/5. The same pattern repeats at every step.
How to Use the Chart
- Decide what you want in focus. For a blurred background, choose a small number. For a deep scene, choose a larger one.
- Set the aperture, then adjust shutter speed or ISO to keep the exposure balanced.
- If you move one stop smaller, for example f/4 to f/5.6, you can double the shutter time or double the ISO to match.
- Check the sharpest range of your lens. Many lenses look best two or three stops from wide open, and very narrow settings can soften fine detail through diffraction.
- Remember that the maximum opening is printed on the lens barrel, and it limits your chart.
FAQ
Is a smaller f-number always better?
No. A wide opening gives more light and blur, but also thinner focus and often softer corners. Choose by the result you want.
Does sensor size change the f-stop?
The f-number describes light intensity, so exposure is the same at a given setting. Depth of field does shift with sensor size and distance, so a larger sensor tends to give a shallower look at the same f-number and framing.
Reading the Chart in Practice
- Wide settings such as f/1.4 to f/2.8 suit dim light and subject separation.
- Middle settings such as f/5.6 to f/8 suit everyday sharpness.
- Narrow settings such as f/11 to f/16 suit scenes with depth.
The Short Version
The f-stop chart is a ladder where each rung halves the light. Learn the series f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11 and f/16, and you can balance aperture, shutter speed and ISO with confidence.
