Next, we need to look through our camera / lens to establish if all of the subject field can be sharply captured in one shot. In the peppercorn image (figure 3), the subject field includes all of the peppercorns present, not just anyone peppercorn. We first need to decide how much of our subject we wish to be in focus. The first step in the stacking process requires a bit of observation and decision-making. Focus Stacking in Macro Photography Focus Stacking – The First Steps Figure 3: A Peppercorn Review (Using a stack of 29 slices captured with a Canon 100mm f/2.8L Macro lens) The second more common application of the Focus Stacking process is in Macro photography. Figure 5: Textures of a Butterfly Wing (Using a stack of 25 slices captured with a Canon MP-E 65mm f/2.8 1-5x Macro lens) Next, we scale and align the layers, determine the sharp parts of each layer and employ masks to hide the out of focus regions of each layer, yielding a single image completely in focus. These images are combined in Photoshop (or a similar application) as layers. Alternatively, we might take one image where the foreground is in focus, another where the midground is in focus and a third which the background in focus (with the camera mounted on a tripod). To accomplish this, we might use a small aperture setting (f/22 or f/32) or we might attempt to apply an appropriate hyperfocal distance, which may or may not be effective. In this type of photography often, wish to capture the foreground, midground and background in clear detail. Two common photographic applications lend themselves to this technique. This is similar to the process of High Dynamic Range (HDR) photography where images of differing exposure are combined to generate a final image containing an expanded dynamic range of exposure. These images (referred to as a “focus slices”) are then combined using specialized software to consolidate all of the sharp regions into a single sharp image. In Focus Stacking, we collect multiple images of a single subject where each image allows the clear and focused capture of different parts of the subject. So how do we obtain images where the entire field of subjects is clear and in focus when the depth of field too small? In these cases, we employ a technique called “Focus Stacking”. Figure 3: A Peppercorn Review (Using a stack of 29 slices captured with a Canon 100mm f/2.8L Macro lens) Figure 4: Table Salt (Using a stack of 48 slices captured with a Canon MP-E 65mm f/2.8 1-5x Macro lens) For example, in the image of the peppercorns (figure 3), the apparent depth of field only covers the depth of one individual peppercorn. In small subjects that require greater magnification, increasing the aperture often fails to yield a sufficient increase in the depth of field to be useful. Unfortunately, in true Macro photography, this is not the case. We adjust the lens aperture to influence the depth of field, where smaller the apertures (higher “f-numbers”) result in a greater depth of field. Why differentiate between the two? In Close-up photography all of the typical photography concepts apply, especially that of depth of field (the amount of your image that is clear and in focus). In true Macro photography, the subject’s size is generally equal to or smaller than the camera’s sensor. In Close-up photography the subject is generally smaller than a loaf of bread (my rather arbitrary upper-end definition) but larger than the size of the camera’s sensor (roughly the size of a postage stamp). Generally, Macro photography is sub-divided into two arenas: Close-up photography and true Macro photography. Figure 2: Ear Jewelry – Up Close (Using a stack of 15 slices captured with a Canon 100mm f/2.8L Macro lens) All of these subjects fall into the realm of Macro photography. We might be interested in capturing images of that cool looking flower, documenting up-close, a piece of jewelry (figure 2), showing common spices in an uncommon way (figures 3 and 4) or showing the intricate texture of a butterfly wing (figure 5). Macro photography is the field in photography related to capturing images of small subjects. Share on Twitter Sunflower bud (Using a stack of 20 slices captured with a Canon 100mm f/2.8L Macro lens)
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