You’ve been photographing plants since 1977, when you received a 35 mm SLR camera as a graduation gift. What kind of cameras and equipment are you using now?
I am using Nikon cameras and lenses. I have an F4 and F3 for film photography and a D200 for digital work. I prefer the film for several reasons – the main overarching reason is that I believe it more fully embraces the art and challenges of photography. Lenses include wide angle (17–35, 28 mm), macros (105 and 200 mm), and short to long telephotos (70–200, 300, 400, and 600 mm). I often use extension tubes and diopters to increase image size and diffusers and umbrellas to control light. And I always use gray cards to determine exposure.
Tell us about the challenges of photographing trees, especially in the small format of the laminated guides.
Obviously trees do qualify as content for plant photography, but they are vastly different subjects compared to herbaceous plants. This is because of their vast size. Making a portrait of a tree is not really even possible, at least not in the same way a portrait is made of an herb. A different approach is necessary for trees, one that implements close-ups of small portions of the tree. A photographic challenge for the guide was in combining images of leaves and fruits in the same photo in order to present diagnostic information helpful for identification. For a few species, like elms, the fruits are produced before leaf-out. Another challenge was in representing the natural variation in shape and size of the leaves. The small format of the pocket guides made it unlikely that images of entire trees (the complete individual tree) would be useful, as very little of the tree’s features would be discernible.
Since the leaf is the single most important diagnostic characteristic of trees, I decided that showing a few to several leaves detached from the tree was the best way to visualize their morphology. Some leaves in each image were turned over to provide views of both the top and bottom surfaces.
Thomas Rosburg, author of Trees in Your Pocket: A Guide to Trees of the Upper Midwest