Calculator and apparatus for macrophotography

A calculator device for use with a camera and variable power electronic flash unit used in macrophotography comprising:

• a body member having spaced apart upper and lower members with interconnected end portions, the members having parallel, longitudinally-extending confronting edges defining a guide path;
• a sliding member having opposed edges guided by said guide path for translation with respect to said body member;
• a first set of cooperating scales positioned on adjacent portions of one side of said body member and a corresponding side of said sliding member, one scale of said first set being a ratio scale having spaced apart indicia representative of the reproduction ratio between the size of the object being photographed and the size of an image of the photographed object on film within the camera, a second of said first set being a sensitivity scale having spaced apart indicia representative of the sensitivities of various types of film used in the camera;
• a second set of cooperating scales positioned on adjacent portions of the other side of said body member and said sliding member, one scale of said second set having spaced apart indicia representative of values obtained from said sensitivity scale of said first set of cooperating scales, another scale of said second set having spaced apart indicia representative of different camera exposure aperature sizes;
• and
• a third set of cooperating scales positioned on adjacent portions of the body member and sliding member, one scale of said third set having spaced apart indicia representative of the distance between the object being photographed and the flash, another scale of said third set having spaced apart indicia representative of the variable power ratio of the electronic flash unit, the second and third sets being positioned on said body member and said sliding member in such manner that adjustment of the relationship between the scales of one of said second and third sets automatically adjusts the relationship between the scales of the other of said second and third sets.