EXAMINATION OF CONODONT ELEMENTS VIA FOCUS-STACKED PHOTOGRAPHY

Photography is a vital process in the modern documentation of paleontological finds. Having accurate, in-depth pictures is essential, as certain physical features are often used to identify and categorize specific organismal groups and species. Technological advances in both photography and microscopy have greatly increased the ability of researchers to define traits earlier scientists may have been unable to determine in microscopic and small macro specimens. High-resolution microscopy includes the use of scanning electron microscopes (SEM) and transmission electron microscopes (TEM), which are able to analyze the surface of objects smaller than a nanometer, but require expensive equipment and regular maintenance. The optics, mechanics, and picture resolution of current digital single-lens reflex (DSLR) cameras likewise possess technologically-improving greater ranges of focus, precision, and detail at a relatively lesser cost, however, photographic detail is restricted by lens type and depth of field.

Focus-stacked photography/imaging is a recent technique developed to generate an image of an object entirely in focus from a set of pictures. For this study, utilizing a DSLR camera and attached objective lens, multiple photographs were taken at set distances in order to capture various focal points of the subject. The images were then stacked together in the computer program Helicon Focus 7 to produce a single picture of the subject. Focus-stacked images provide excellent depth of field and detail of the subject, while retaining the original color and other aspects that may be lost using other macrophotography techniques.

Resolution of the focus-stacking method was tested by analyzing conodont elements collected from the Pennsylvanian Lower Brush Creek marine unit. Conodont elements were extracted via four differing strengths of formic acid solution: 10% buffered, 10% unbuffered, 9.25% unbuffered, and 8.5% unbuffered. Visual examination with stacked images revealed no observable differences in the quality of the elements between each of these conditions. The elements are on the scale of millimeters to hundreds of microns in length and their serrations are on the scale of only tens of microns. Smaller serrations less than 20 microns in width are easily resolved in the final stacked images.