Infrared focus, often referred to in cameras as the IR setting, is the adjustment required when focusing with infrared-sensitive film or digital sensors. Infrared light focuses slightly differently from visible light, so using the IR focus ensures that images remain sharp when capturing infrared photography.
This focus adjustment is particularly important in black-and-white infrared photography, where precise sharpness is essential for capturing fine details and textures. Photographers using infrared techniques benefit from understanding infrared focus to maintain image clarity and achieve the characteristic effects of infrared imaging.