Field resolution tests with the Metrogon lens

The first portion of this treatise is devoted to a compilation of general knowledge concerning photographic resolution testing - an explanation of certain optical terms; the drafting of resolution targets; methods for averaging resolution values, measured at various positions on the format, to obtain one over-all value for an exposure; and a description of the factors involved in conducting the photographic operations. In the second part of the paper, analyses of the results obtained from line-target resolutions are made with the purpose of determining those combinations of aperture, filter, and shutter speed which result in high photographic resolutions. This information will be of particular value to a person who is called upon to operate the camera, but whose knowledge of photography is limited. The final section includes a determination of that position of photographic focus in an aerial camera which produces best over-all definition. All phases of the resolution testing program described herein require no complex scientific equipment other than cameras for their execution. This system of testing produces adequate data and is sufficiently simple to warrant its consideration as a field method in which trained laboratory personnel, although desirable, are not essential for its accomplishment --Introduction, page 4