Optical instrument evaluation using modulation transfer function chart

A method of evaluating an optical instrument comprising steps of:

• viewing a plurality of sets of converging lines positioned on a corresponding plurality of blocks of like color, said plurality of sets of converging lines and said blocks defining a corresponding plurality of different contrast levels therebetween;
• scanning said plurality of sets of converging lines through an optical instrument;
• determining line frequencies along each of said plurality of sets of converging lines at which a user of said optical instrument is unable to differentiate said converging lines;
• and
• recording said line frequencies.

A chart for evaluating an optical instrument, comprising:

• a plurality of blocks having like color and varying color intensities;
• a plurality of sets of converging lines, each of said sets of converging lines being located within an associated one of said blocks and having a known contrast level in comparison thereto, said converging lines being of substantially like color as said blocks;
• and
• a measurement scale for indicating line frequency along said plurality of sets of converging lines.

A chart for evaluating an optical instrument, comprising:

• a plurality of substantially aligned blocks of like color, color intensities of said blocks ranging from near-white to near-black;
• a plurality of substantially aligned sets of converging lines, each of said sets of converging lines being located within an associated one of said blocks and having a known contrast level in comparison therewith, said converging lines having substantially like color and color intensity as at least one of said blocks, and said converging lines ranging in frequency from 1 line pair per millimeter to 10 line pairs per millimeter;
• and
• a measurement scale substantially aligned with said plurality of converging lines, for indicating line frequencies along said converging lines.

A method of testing an optical instrument, comprising steps of:

• providing a chart comprising
• a sequence of blocks of varying color intensities,
• a plurality of sets of converging lines, each of said sets of converging lines being located within an associated one of said blocks and having a known contrast level in comparison therewith, said converging lines being substantially identical in hue, and
• a measurement scale for indicating line frequency along said converging lines;
• scanning said sets of converging lines with said optical instrument;
• and
• using said measurement scale to determine line frequency along said converging lines at which a user of said optical instrument is unable to differentiate said converging lines.