description of elements on main screen of DOFMaster LE

Use the menu to access other screens

menu screenshot

Modify the lens focal lengths shown on the main screen

lens setup screenshot

Select the film format

film format screenshot

Edit the circles of confusion for each film format

circle of confusion screenshot

Set the location of infinity on the distance scale

distance scale setup

Restore lens focal lengths and circles of confusion to default values

restore defaults screenshot

Hyperfocal distance, near distance, and far distance are calculated using the following equations (from Greenleaf, Allen R., Photographic Optics, The MacMillan Company, New York, 1950, pp. 25-27):

Hyperfocal distance:

hyperfocal distance equation

Near distance of acceptable sharpness:

near distance equation

Far distance of acceptable sharpness:

far distance equation



is the hyperfocal distance, mm


is the lens focal length, mm


is the focus distance


is the near distance for acceptable sharpness


is the far distance for acceptable sharpness


is the f-number


is the circle of confusion, mm

f-number is calculated by the definition N = 2i/2 , where i = 1, 2, 3,... for f/1.4, f/2, f/2.8,...