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Close-up lens
In photography, a close-up lens (sometimes referred to as close-up filter or a macro filter) is a simple secondary lens used to enable macro photography without requiring a specialised primary lens. They work like reading glasses, allowing a primary lens to focus more closely. Bringing the focus closer allows the photographer more possibilities.
Close-up lenses typically mount on the filter thread of the primary lens, and are often manufactured and sold by suppliers of photographic filters. Nonetheless, they are lenses and not filters. Some manufacturers refer to their close-up lenses as diopters, after the unit of measurement of their optical power.
Close-up lenses do not affect exposure, unlike extension tubes, which also can be used for macro photography with a non-macro lens.
Close-up lenses are often specified by their optical power in diopters, the reciprocal of the focal length in meters. For a close-up lens, the diopter value is positive: the bigger the number, the greater the effective magnification.
Higher quality achromatic lenses commonly lack a strength specification in diopters. It can be inferred as the reciprocal of the maximum specified working distance in meters (i.e., a lens with a maximum working distance of 25 cm has a strength of +4 diopters).
Several close-up lenses may be used in combination; the optical power of the combination is the sum of the optical powers of the component lenses. For example, a set of lenses of +1, +2, and +4 diopters can be combined to provide a range from +1 to +7 in steps of 1.
Close-up lenses change both the maximum and minimum focus distances of a lens. The range can be rather small.
Adding a close-up lens to a lens focused to infinity changes the focus point to the focal length of the close-up lens, that is, the inverse of its optical power. This is the combination's maximal working distance:
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Close-up lens AI simulator
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Close-up lens
In photography, a close-up lens (sometimes referred to as close-up filter or a macro filter) is a simple secondary lens used to enable macro photography without requiring a specialised primary lens. They work like reading glasses, allowing a primary lens to focus more closely. Bringing the focus closer allows the photographer more possibilities.
Close-up lenses typically mount on the filter thread of the primary lens, and are often manufactured and sold by suppliers of photographic filters. Nonetheless, they are lenses and not filters. Some manufacturers refer to their close-up lenses as diopters, after the unit of measurement of their optical power.
Close-up lenses do not affect exposure, unlike extension tubes, which also can be used for macro photography with a non-macro lens.
Close-up lenses are often specified by their optical power in diopters, the reciprocal of the focal length in meters. For a close-up lens, the diopter value is positive: the bigger the number, the greater the effective magnification.
Higher quality achromatic lenses commonly lack a strength specification in diopters. It can be inferred as the reciprocal of the maximum specified working distance in meters (i.e., a lens with a maximum working distance of 25 cm has a strength of +4 diopters).
Several close-up lenses may be used in combination; the optical power of the combination is the sum of the optical powers of the component lenses. For example, a set of lenses of +1, +2, and +4 diopters can be combined to provide a range from +1 to +7 in steps of 1.
Close-up lenses change both the maximum and minimum focus distances of a lens. The range can be rather small.
Adding a close-up lens to a lens focused to infinity changes the focus point to the focal length of the close-up lens, that is, the inverse of its optical power. This is the combination's maximal working distance: