Aperture
The lens opening that admits light, expressed as f-number (e.g., f/1.4, f/2.8). Lower f-number = wider opening = more light + shallower depth of field.
The aperture is the iris inside a lens. f-number = focal length ÷ effective aperture diameter.
Stops
Each full stop doubles or halves light: f/1.4 → f/2 → f/2.8 → f/4 → f/5.6 → f/8 → f/11. One stop wider = double the light = halved shutter speed at the same ISO.
In smartphones
Fixed apertures (no iris) — typically f/1.6 to f/2.8 on the main camera. Wider apertures need larger lenses, which is why ultra-wide cameras tend toward f/2.2 and telephoto toward f/2.8.
Practical sweet spots
Most lenses are sharpest 1–2 stops down from wide open. An f/1.4 prime peaks around f/2.8–f/4. Use wide-open for shallow depth or low light; stop down for landscapes and group shots.
How to use Aperture in a real comparison
The lens opening that admits light, expressed as f-number (e.g., f/1.4, f/2.8). Lower f-number = wider opening = more light + shallower depth of field. In practice, this is most useful as one part of a decision rather than a standalone quality badge. Compare it alongside the workload, room, ecosystem, budget, and ownership constraints that apply to you; the strongest published figure is not automatically the best outcome for every buyer.
What to check next
Open a product page and check the stated value, configuration, price, and related trade-offs before treating this term as decisive. It is especially relevant in .
Avoid the one-number trap
Manufacturers can describe the same capability under different conditions. Compare like-for-like variants, check the unit and test condition where available, and use a head-to-head page to see whether a measurable difference is material for your own use.
vsMars presents structured catalog values to make trade-offs legible. The linked product and spec pages are the right place to inspect the underlying values before buying.