Placement considerations when using linear scales in photographs

This paper considers several aspects of using linear scales in photographs. It describes a method used to measure the variations in scale size and subject size when the two are not on the same plane in a photograph. It discusses the results achieved from experiments using a measuring device and different lenses and lens settings. The results demonstrate the marked differences in measured size that occur as the scale and subject distances vary. The paper provides evidence that placement of scales within the field of view in photographs is critical for useful information to be extrapolated from the scale.