Answer
What is aperture in photography?
Aperture is the size of the lens opening that lets light through to the sensor. Measured in f-stops (f/1.4, f/2.8, f/8). Lower numbers = bigger opening = more light and shallower depth of field.
The two things aperture controls
- How much light hits the sensor. Bigger opening = brighter exposure.
- Depth of field. Bigger opening = more blurred background.
The f-stop scale
f/1.4 → f/2 → f/2.8 → f/4 → f/5.6 → f/8 → f/11 → f/16. Each step halves the light. Counter-intuitive: smaller f-number = larger opening.
Practical guide
- f/1.4-f/2 — portraits, low light, dramatic background blur
- f/2.8-f/4 — general photography, environmental portraits
- f/5.6-f/8 — landscape and group shots (sharpest aperture on most lenses)
- f/11-f/16 — landscape with deep depth of field, but diffraction softens detail
Why fast lenses are expensive
An f/1.4 lens requires bigger, more precisely ground glass than an f/4 lens. Premium fast primes cost $800-2,500; budget ones with smaller maximum apertures cost $200-400.
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