Method Note 1

Resolution tests were run at a working distance that allowed full frame exposure of the lens resolution chart. The chart was illuminated with a soft box adjusted with a flash meter at each aperture. The camera was on a Bogen 3033/Arca B1 tripod/head combination with a bean bag weighing down the tripod/head. Two exposures at 1/250th were taken at each aperture on Kodak Technical Pan rated at ISO 25 and developed in Technidol. Mirror lock up was used on each exposure. The central autofocus point was centered over the center pattern for each exposure. No focus bracketing was used. Line patterns were read under a compound brightfield microscope at a magnification of 40X.

Measurement were made at the center pattern, a middle pattern, and the far upper right pattern on the two exposures. The highest resolution score for each aperture was recorded. Autofocus function occasionally resulted in variations in lpm scores at the same aperture calculated as described on the poster. Center weighted lens resolution was determined by weighting resolutions as: center - 60%; mid-area - 30%; field edge - 10%.

Edmund Scientific Lens Resolution Chart