These two images of blades of grass wet with raindrops illustrate a digital solution to a technical photographic problem that could not be solved using film—and cannot be achieved in a solo digital capture. Some things just take more than one.
Consider that as you get very close to a macro subject that depth-of-field gets very shallow. Now suppose you want a great deal of your subject in focus—like all the drops of rain on the blades of grass shown in these two images. At the same time, you want a nice, soft focus background. Yum!
You can try a conventional approach: stopping your macro lens all the way down to the smallest aperture. Unless you are truly parallel to the subject, and the subject doesn’t have much width, you will not be able to get everything you want in focus. And stopping the lens all the way down probably means that the background soft focus will not be quite so dreamily soft.
The digital answer is focus stacking, which involves shooting multiple images at different focal points. Eac individual image can be shallow in terms of the depth-of-field.
The top image is made up of five orginals, and the bottom from seven. If you magnify the bottom image enough you’ll see a bit of unsharpness—but this comes from movement of the blade of grass in the wind, not technical focusing issues.
Once you have your set of originals, they can be aligned and combined in a Photoshop stack, as I explain in detail in Creative Close-Ups on pages 124-131.
View this image larger.