There was a time when professionals considered a zoom an amateur's lens. Macro focusing capabilities permit a 1:2.2 (approximately half-life size) reproduction ratio at its close focus position.
#Vivitar 70 210 mm series
The Series 1 70-210 is surprisingly compact and light for a zoom lens with an f3.5 maximum aperture. It consistently produces photographic images that are indistinguishable from those taken with fixed focal length lenses. This lens shows very fine resolution and contrast throghout its working range. The result is a patented zoom lens that corrects aberrations at close focus, optimizes performance in the normal zoom range, and is both focused and zoomed with one simple control. A computer simulation established that these same moving elements could be used for close focusing, provided they were made to move in proper relationship to one another and in a different manner for the "zoom" action. Before the advent of the 70-210mm Series 1 lens, there were acceptable zoom lenses but none had a macro focusing capability.Ī novel solution to the close focusing zoom problem was suggested by the fact that the zooming elements in a zoom lens are designed to move with respect to each other. A simple corrector lens could be used to compensate for aberrations in close focusing, but its effect would be limited to one specific focal length only. The closer such a lens is made to focus, the more apparent the degradation. The close focusing capabilities and the reproduction ratio of a lens are severely limited by the degradation of the image introduced by focusing only the front element. **) Some basic information is missing in the specification as it was not provided by the manufacturer.Ĭonventional zoom lenses have normally been focused by moving the front group of elements only. Vivitar Series 1 booklet (August 1976).*) Sources of data: Manufacturer's technical data
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