Combination image of cactus with spines. Deep focus stack with 28 images, front to back, (left) and single image from center of stack (right). Nikon D800, 105 mm F2.8 Micro Nikkor, SB 910 flash and circular diffuser.
There are many times when a single image, even at the smallest aperture simply will not produce enough depth of field (DoF) to render the image sharply. This is regardless of the lens quality, camera or technique. The image above is a demonstration from a recent Nature and Macro Photography Workshop.
We have learned that DoF is dependent primarily on Aperture. (The bigger the aperture number; the bigger the DoF.) But DoF is also dependent upon Subject Distance, and lens Focal Length. As we get closer to the image and increase our lens focal length in macro photography, the total measured distance of the DoF gets smaller. Working in close-up am macro photography we are working against ourselves when it comes to DoF. Therefore, we need to improve upon this fault.
To extend the DoF we can now rely upon computer blending of several images into one with greatly extended DoF. Each image is focused at a different distance from the lens. An additional benefit of this technique is the use of a middle range, somewhat sharper aperture. When blended in computer software, part of the resultant image uses near focus detail, part uses mid-focus detail and another uses far focus detail, and so on. Often, as many as 10 or more sequential images are “stacked” and blended into one.
This blending process can include the use of multiple layers in Photoshop or free software called CombineZ or Zyrene Stacker. However, the most powerful software and today’s industry standard is Helicon Focus. The current version is 6.3.7 and its cost ranges from $30 to $200 depending on length of subscription service and number of computers licensed.
Nikon D2Xs, 50 mm flat field EL Nikkor lens on bellows, two SB-800 flashes, tripod. Image magnification in camera: 1.6X.
In this image (above) of the head of a bee 53 individual images with a different point of focus from the antennae to the rear of the head were made. Each image was spaced 0.005 inch from one another from the front to the back. These multiple images spanned the overall distance of o.265 inch, (or about a quarter of an inch).
So as you can see, focus stacking can help produce a little more DoF or a great amount as in the bee. It is also useful in landscape photography to produce foreground, midground and background in equally sharp focus.
Copyright © 2015 Brian Loflin. All rights reserved.