"Macro" is an abbreviation of "photomacrography" which by strict definition is the capture of subjects at 1:1 or greater magnifications. Here's a good recent paper on the subject (circa 2006): http://www.a-p-s.org.au/pdfs/articles/macro.pdf
When applied to lenses, originally the term "macro lens" meant a lens which was specially corrected for photomacrography use, most usually able to achieve magnifications in the 1:4 to 1:1 range without focusing mount or optical add-ons additions. The 50mm macro lens with 1:2 maximum magnification in 35mm film work became a de standard as it meant a lens which was usefully sized and functional in general purpose use without need for additional focusing mount extension. Then the marketing goons came along and destroyed the meaning of the term "macro" by applying the macro label to anything that could focus closer than a yard and perform just slightly better than a Coke bottle bottom, all of a sudden expanding the range of macro lenses to include all sorts of useless and crappy zoom lenses. So the answer to "what is necessary and sufficient for a lens to be called macro?" in the modern age is that some marketing goon thinks they can suck another few dollars out of your pocket by adding the term to a lens name. Godfrey On Fri, Jun 15, 2012 at 11:10 AM, Igor Roshchin <[email protected]> wrote: > > > ... Well, I understand the meaning of the word. But what does it > actually mean in the lens designation? > > The new Sigma 18-250 lens is called "macro" "with a maximum > magnification ratio of 1:2.9": > http://www.dpreview.com/news/2012/06/15/Sigma-launches-18-200mm-F3-5-6-3-Macro-HSM-superzoom-lens > > One of my older version Tamron zooms (70-300/4-5.6) and Sigma 24mm /1.8 EX DG > are also marked as "Macro". > While Sigma 24/1.8 goes to short focusing distances (about 18 cm / 0.6 > ft), Tamron - doesn't (the shortest focusing distance is about 50 or 70 cm). > In contrast, D FA 100/2.8 Macro - has a clear long tail of focusing > distances where you achieve the macro regime. > > So, what is necessary and sufficient for a lens to be called macro? > > Igor > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- Godfrey godfreydigiorgi.posterous.com -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
