Translation guide
The f-number (or f-stop) is a measure of lens aperture in photography. In Japanese, it is expressed using katakana or the letter F followed by the number.
What is the f-number?
Expressing the aperture value of a camera lens
The standard term for f-number in Japanese. 'F' is pronounced エフ, and 値 means 'value'. Used in technical and everyday contexts.
The f-number of this lens is 2.8.
The smaller the f-number, the easier it is to blur the background.
A direct loan from English, used in some technical contexts. Less common than F値.
Lenses with small f-numbers are expensive.
Literally 'aperture value'. Sometimes used interchangeably with F値, but can also refer to the physical aperture diameter. More common in technical manuals.
Adjust the exposure by changing the aperture value.
In Japanese, f-numbers are typically written with a capital 'F' followed by the number, e.g., F2.8. The slash notation (f/2.8) is less common but understood. When speaking, say エフ (F) and then the number.