Home
Back
F-Stop Formula:
| From: | To: |
F-stop (f-number) is a dimensionless number that represents the ratio of a lens's focal length to the diameter of the entrance pupil (aperture). It's a key concept in photography that controls the amount of light entering the camera and affects depth of field.
The calculator uses the f-stop formula:
Where:
Explanation: The f-stop number indicates how much light the lens aperture admits. Lower f-numbers mean larger apertures and more light, while higher f-numbers mean smaller apertures and less light.
Details: Understanding f-stop is crucial for controlling exposure and depth of field in photography. It helps photographers achieve proper lighting and desired focus effects in their images.
Tips: Enter focal length and aperture diameter in millimeters. Both values must be positive numbers greater than zero for accurate calculation.
Q1: What are common f-stop values?
A: Common f-stop values follow a standard sequence: f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22. Each step halves the amount of light.
Q2: How does f-stop affect depth of field?
A: Lower f-numbers (wider apertures) create shallower depth of field (more background blur), while higher f-numbers (smaller apertures) create greater depth of field (more in focus).
Q3: Why is f-stop called "f-stop"?
A: The "f" stands for focal length, and "stop" refers to the stepped aperture settings that photographers use to control exposure.
Q4: What's the relationship between f-stop and exposure?
A: Each full f-stop change either doubles or halves the amount of light reaching the camera sensor, working in conjunction with shutter speed and ISO to control exposure.
Q5: Can I use this calculator for any lens?
A: Yes, this formula works for any photographic lens as long as you have accurate measurements of focal length and aperture diameter.