<P> Round convex mirrors called Oeil de Sorcière (French for "sorcerer's eye") were a popular luxury item from the 15th century onwards, shown in many depictions of interiors from that time . With 15th century technology, it was easier to make a regular curved mirror (from blown glass) than a perfectly flat one . They were also known as "bankers' eyes" due to the fact that their wide field of vision was useful for security . Famous examples in art include the Arnolfini Portrait by Jan van Eyck and the left wing of the Werl Altarpiece by Robert Campin . </P> <P> The image on a convex mirror is always virtual (rays haven't actually passed through the image; their extensions do, like in a regular mirror), diminished (smaller), and upright . As the object gets closer to the mirror, the image gets larger, until reaching approximately the size of the object, when it touches the mirror . As the object moves away, the image diminishes in size and gets gradually closer to the focus, until it is reduced to a point in the focus when the object is at an infinite distance . These features make convex mirrors very useful: since everything appears smaller in the mirror, they cover a wider field of view than a normal plane mirror does . </P> <Table> Effect on image of object's position relative to mirror focal point (convex) <Tr> <Th> Object's position (S), focal point (F) </Th> <Th> Image </Th> <Th> Diagram </Th> </Tr> <Tr> <Th> S> F, S = F, S <F (\ displaystyle S> F, \ S = F, \ S <F) </Th> <Td> <Ul> <Li> Virtual </Li> <Li> Upright </Li> <Li> Reduced (diminished / smaller) </Li> </Ul> </Td> <Td> </Td> </Tr> </Table> <Tr> <Th> Object's position (S), focal point (F) </Th> <Th> Image </Th> <Th> Diagram </Th> </Tr>

Where are convex mirrors used in everyday life