by Marc Dilley
Every May I get excited about the appearance of one of my all-time favorite wildflowers, Tweedy’s Lewisia. I don’t know if it’s the coastal weather we’ve had all “spring” or just that I’ve pushed into new areas this year, but I’ve seen more totally cool plants this season than in the last five combined. This season I have focused on the Tumwater Canyon and discovered spots with hundreds of plants, many in high drama positions on cliff edges and in cracks that any climber would appreciate.
Photographic opportunities and challenges were legion, and I have made about twenty forays so far this season… but who’s counting? Testing my ingenuity and patience has been the issue of setting up the tripod in uneven, airy and slippery terrain. Meanwhile, some beautiful photos have been lost due to the inaccessibility of the flowers I’ve stalked. One spot that particularly stands out in my mind was a small semi-circular stone amphitheater whose 20-foot vertical walls were festooned with Lewisia flowers, hanging over the lip of the face. It would have been nice to get closer, but I wasn’t able to rent a hovercraft.
Notes on the photographs: Since I want crystal clarity in my photographs from the nearest to the farthest points of the image, I had to utilize specialized techniques to achieve what is not possible in close-up photography using the traditional method of stopping down the lens to it’s smallest aperture.
The closer a lens gets to a subject, the narrower the depth of field becomes. Depth of field (DOF) is simply that area of the subject that is in perfect focus. DOF can be controlled somewhat with aperture selection of the lens: the larger the f/number, or smaller the aperture (opening) of the diaphragm, the greater the DOF will be. While this technique is adequate at macro distances, to achieve a uniformly crisp image in close-up situations DOF’s with even very small apertures become so narrow that extremely blurry areas in front of and behind the subject will occur. To work around this problem and produce these images, which are entirely sharp, I employed the following techniques:
First, the tripod holding the camera was positioned and held rock steady. Because the tripod frequently sat on spongy forest duff or sloping mossy stones; I used my foot to weight a bungee cord tied around the head of the tripod. This provided on-demand directional weight to the tripod, keeping it completely solid during the shoot.
Next I took a number of shots, each with identical exposure settings, but with one important difference–the point of focus is varied for each image. I take the first exposure focused on objects closest to the camera lens and finish the series focused on those objects that are farthest away. The number of shots I take depends on how close the subject is and the magnitude of depth.
Back at the computer, all images for one composite picture are processed precisely the same. At this point the magic happens: Photoshop is able to meld all the images together, saving the in-focus areas of each shot and culling out the fuzzy areas. It then seamlessly combines all the sharp pieces into one crystal-clear, flat image. The number of shots employed to make a final image varied from two for “Lewisia, Evening Light”(bracketed exposures + diff. focus) to seven for “Sword Fern” (below).
This article was originally published on 6/03/10.