Life Histories of Cascadia Butterflies

Photographic Techniques

58 life histories of cascadia butterflies Photographic Techniques Documenting the immature stages of butterflies can be done by killing and preserving them in a liquid preservative such as alcohol, or by photography. There are pros and cons to each method. Preserved specimens in glass tubes and flasks are bulky and need to be maintained, and specimens tend to lose their natural colors; however, the finest structural details are preserved for later study. Larvae must be killed at each stage to record the entire life history, and this can be a problem when only a few specimens are available. Photography records natural colors faithfully and aesthetically, often in natural surroundings, without killing the subject, permitting all stages to be documented using a single individual (with a bit of luck!). However, each photograph records only one view or perspective, and minute details are typically not visible in photographs. This chapter describes some of the photographic techniques available for documenting the immature stages of butterflies. Macro Photography Equipment: Photography of butterfly immature stages often involves some very small subjects, down to 0.5 mm. To obtain quality images of such tiny subjects, a digital single lens reflex (SLR) camera and a special macro lens are required, together with other equipment for stabilizing the camera and lighting the subject. While larger specimens can sometimes be photographed in nature, most “super macro” photography must be done indoors under carefully controlled conditions. Most of the photographs in this book were taken by the authors using a variety of Canon digital SLR cameras and a 1–5x macro zoom MP-E 65 mm Canon lens, resulting in images up to 8x natural size (equivalent to 8:1 in film cameras). Super macro photography is greatly affected by vibration; at such high magnifications, even the tiniest vibrations can blur an image. Equipment needed for high magnification work includes a good solid tripod and an electronic remote shutter release to reduce camera shake. Additionally the camera should be capable of “mirror up,” also known as delayed shutter release; this allows the SLR camera to pause for a moment after the mirror flips up but before the shutter releases to further reduce vibration. Lighting can be accomplished with dual adjustable light sources, or with dual flashes. Another important accessory is a rack-and-pinion focusing platform that mounts between the tripod and the camera. This apparatus is very useful for centering and fine focusing a tiny subject, and it is mandatory if digital stacking is used. Depth of field is always a problem in macro photography and a major problem with super macro work. When depth of field is poor, a thin slice of the subject will be in focus while closer and more distant parts are blurred. Depth of field can be improved by adjusting the camera to a small aperture (larger f-stop number) but this requires a longer exposure time to compensate for the light reduction, and there are limitations on how much the depth of field can be improved in this manner. Another technique is to use digital stacking, a method in which a series of photographs is taken, focusing first on the very front of the object and in tiny increments ever deeper into the subject until the back is reached. A very stable tripod and a rack-and-pinion focusing rack are needed, as well as a very still, cooperative subject. Special computer software is used to process the stack of digital photos to create a single composite picture that assembles all the best-focused parts of the individual photos. Some of the images in this book are the product of digital stacking. The technique is fairly time consuming, but the results can be excellent. Techniques: Most other suggestions are much the same as in normal photography. A still subject is always important. Larvae are generally most “cooperative” under cool 59 photographic techniques | how to use this book conditions (10–15 °C). If a larva is “squirmy,” it can be cooled gently in the refrigerator, but usually it is best to leave it alone for a while and check back later; even the most uncooperative subjects will eventually stabilize and become stationary. Lighting can be hot and uncomfortable for larvae, causing excessive movement. Adjustable intensity lighting can be helpful; lights turned to a dim setting and very gradually brightened to higher intensity are often tolerated better than a sudden bright light. It is always advisable to be very familiar with your equipment so you...