4x5

4x5 is a dimension expressed as four by five units. In mathematics, it denotes the product of 4 and 5, which equals 20.

In photography and film, 4x5 inches refers to a large-format sheet film size. The film measures 4 inches by 5 inches (approximately 101.6 by 127 millimeters). This format is notable for high image resolution and for enabling camera movements that control perspective and depth of field. It was widely used with field, studio, and architectural cameras from the early 20th century through much of the century. Cameras designed for this format include field models as well as monorail designs, often paired with lenses ranging from very wide to long focal lengths.

Prints and aspect ratios also use the 4x5 designation. A 4x5-inch print corresponds to a small photo print size, while a 4:5 aspect ratio describes the proportional relationship between width and height. The 4:5 ratio is common in portrait photography and appears in some digital image crops and social media formats.

Summary: 4x5 can refer to a mathematical product, a historical large-format film size used in photography, or a descriptor for print sizes and aspect ratios, depending on the context.