And when you change focal length, you change the field of view in your image. You might think “why move the camera? Why not just change focus to move the slice of focus along the object?” This technique would work with large objects, but remember that every time you focus you’re actually changing the focal length of your lens a tiny bit. Those images can then be combined to create a finished image. Then I repeat this until I have shot in-focus slices of the entire object. If my depth of field is half a millimeter, then I move the camera forward half a millimeter and take another shot. I shoot a picture where the very front of my subject is in focus. With digital post-production, though, we can combine multiple images that each have shallow depth of field into a finished image with very deep depth of field.įIGURE 3: This is the same raspberry that was shown in Figure 1, but now I’ve shot it with deep depth of field using some specialized hardware and software.Ĭonceptually, the process here is pretty simple. Since the depth of field in figure 2 is shallow, my brain assumes that it must be very small, and that I must be standing very close to it. This toy effect is simply because our brain understands that when you look at something up close, you see very shallow depth of field. For example, if I shoot a landscape shot with a tilt/shift lens, which allows me to greatly shorten the depth of field, the result ends up looking like a toy, or a miniature diorama.įIGURE 2: We’re so used to close-ups having shallow depth of field, that if we shoot a landscape with extremely shallow depth of field, it looks like a miniature.
In fact, we’re so used to macro photos having shallow depth of field that we will often interpret shallow depth of field as an indicator of scale. Getting an image with deep focus becomes very complicated. For example, when shooting with a 1x macro lens at f/4, your depth of field will probably be around half a millimeter!Ĭonsequently, most macro photos have depth of field like the image in figure 1.įIGURE 1: When you get in close, your depth of field will shrink to fractions of a mm. Macro lenses, therefore, are capable of focusing at incredibly short distances.Īs you get closer to your subject, though, your depth of field drops off tremendously.
With most lenses, if you’re close enough to your subject to get macro scale, you’re too close to actually focus the shot. To shoot a macro photo, you need a lens that’s capable of focusing close enough to your subject that you can achieve this 1:1 or better size. (Going to higher magnifications is also considered macro, of course.) That is, the size of the object on your image sensor is actual size. Technically, a macro photo is one that captures your image at a 1:1 scale. And one of the most important macro-related innovations has to do with depth of field. But as you might expect, digital technology, both hardware and software, has made it possible to shoot macro photographs that would have been impossible to achieve with film. Macro photography-the process of shooting extreme close-ups of things-has been popular for as long as there have been cameras.
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