Many SLR and medium-format cameras feature interchangeable focusing screens, allowing photographers to swap the standard screen for one better suited to their shooting needs. Different screen patterns help with composition, alignment, and precise focusing depending on the type of photography being done.
Common types include grid screens, which have thin lines for aligning horizontal and vertical elements-favoured by architectural photographers and for copy work. Plain screens are used for microscope and telescope photography, while Fresnel or split-screen designs assist with focusing long telephoto lenses where other screens may darken. Understanding interchangeable focusing screens allows photographers to optimise accuracy, composition, and usability across various photographic applications.