There is no precise definition of where portrait photography ends and macro photography begins. Macro is the Greek word for large, and it is used for making subjects appear large. A practical way for defining macro photography is by the strength of the lens, or how nearby it can focus. In the old days, a minimum distance of one metre (one diopter) was considered enough, but most lenses will now go to 0.5 metre (2 diopter). Portrait photography ends at about one metre using a 100mm lens. If you want to go any closer, the lens must be mounted further from the camera by means of bellows or extension tubes. One can also make the lens stronger by placing closeup lenses of 1-4 diopters in front.
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