The term "f/1.8" refers to the aperture setting of a camera lens. The "f" stands for focal ratio, which indicates how wide the lens opens to let in light. An f/1.8 aperture allows a large amount of light to enter, making it ideal for low-light conditions and creating a shallow depth of field. This means that the subject can be in sharp focus while the background appears blurred, enhancing the overall composition of the image. Lenses with an f/1.8 aperture are popular among photographers, especially for portrait photography. They are often more affordable than faster lenses, such as those with an f/1.4 or f/1.2 rating. Many DSLR and mirrorless cameras can use f/1.8 lenses, making them versatile tools for both amateur and professional photographers.