Studies in the Resolving Power of Photographic Emulsions III The Effect of the Relative Aperture of the Camera Lens on the Measured Value*

It was found experimentally that, as the relative aperture of the camera lens increases, the lens being substantially “perfect,” the measured value of the resolving power of an emulsion used with it also increases but eventually attains a maximum and then decreases. It is proposed to call this maximum the “maximum lenticular” resolving power of the emulsion. A hypothetical relation is derived for predicting the measured resolving power of a lens-emulsion combination for the maximum lenticular resolving power of the emulsion and the resolving power of the lens on the Rayleigh criterion, assuming the lens to be “perfect.”