Large format refers to any imaging format of 9×12 cm (3-1/2x4-3/4 inch) or larger. Large format is larger than "medium format", the 6×6 cm (2¼×2¼ inch) or 6×9 cm (2¼×3½ inch) size of Hasselblad, Mamiya, Rollei, Kowa, and Pentax cameras (using 120- and 220-roll film), and much larger than the 24×36 mm (0.95×1.42 inch) frame of 35 mm format.
The main advantage of large format, film or digital, is a higher resolution at the same pixel pitch, or the same resolution with larger pixels or grains. A 4×5 inch image has about 15 times the area, and thus 15× the total resolution, of a 35 mm frame.
Large format cameras were some of the earliest photographic devices, and before enlargers were common, it was normal to just make 1:1 contact prints from a 4×5, 5×7, or 8×10-inch negative.
View More On Wikipedia.org