Guest post by Joe Farace
The classic definition of macro photography is that the image projected onto the digital sensor or film plane should be the same size as the subject. At a 1:1 ratio, a digital SLR with a full-sized chip should have the ability to produce life-size magnification and focus on an area as small as 24Ã—36 mm. On the other hand, lens manufacturers sometimes describe a lensâ€™s close-focusing capabilities as â€œmacroâ€ even if it doesnâ€™t quite meet that definition and itâ€™s gradually come to mean being able to focus close enough so the image is life-size or larger when viewing a 4Ã—6 inch print. This only requires a magnification ratio of approximately 1:4.
Conventional wisdom is that close-up photography requires lots of expensive, specialized equipment and while itâ€™s true you can spend lots of money in order to make macro shots, you donâ€™t have to break your piggy bank to shoot macro, no matter how you choose to define it. Hereâ€™s whyâ€¦
Most filter and camera manufacturers offer what are sometimes called close-up â€œfilters.â€ Although not filters in the traditional sense, they look like filters, work like filters and act like filters, so Iâ€™ll call â€™em filters like everybody else. Close-up filters are really supplementary lenses that shorten your camera lensâ€™ close-focusing distance allowing you to get closer to the subject.
Close-up filters are available in different strengths (or diopters) as a set usually includes versions labeled Close-up +1, Close-up +2, and Close-up +4. A diopter is a unit of measurement used to describe the power of a lens and is expressed as the reciprocal of the focal length in meters. For macro shooters on a budget, a complete set of really good close-up filters in 52mm threads should cost about $50.
Tip: Close-up lenses are double-threaded so they can be used in combination with one another but to get the sharpest results itâ€™s a good idea to place the strongest filter closest to the lensâ€™s front element.
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