Close-filters, also known as close-up lenses or macro filters, attach to the front of a lens or lens adapter and extend the close-up range of a digital camera. Though not as high quality as a macro lens, close-up filters are small and lightweight.
Close-up filters are much less expensive than a dedicated macro lenses too. While they can reduce image quality they also provide better magnification than the built-in macro mode found on many digital cameras.
Close-up filters have diopter ratings such as +1, +2, +4, +10 and can be bought individually or in sets. When stacked, they provide more magnification than if only one close-up filter was used.
If you stack filters, the order you do so is important. Always put the strongest filter (highest number) closest to the camera lens, then the next strongest, etc.
If using a standard filter and a close-up filter simultaneously, attach the close-ups first and the filter last.
Because close-up filters can decrease Depth of Field, use a smaller apeture to photograph the subject.