botón de previsionado de profundidad de campo
/botˈon de pɾˌeβisjonˈaðo ðe pɾˌofundiðˈad ðe ˈkampo/
n
English: depth-of-field preview button · 景深预览按钮
Significado：Button that closes the diaphragm so that the relative clarity of various depths can be seen through the viewfinder.