While the total dimensions are confined to the absolute minimum, the new SP AF70-200mm F/2.8 zoom lens is packed with features that allow stress-free photography: a versatile "MFD" (Minimum Focus Distance) of just 37.4" over the entire zoom range; best-in-class maximum macro magnification ratio of 1:3.1 at f=200mm; and an advantageous internal focusing (IF) system. The new tele-zoom lens covers a desirable focal length range of 70mm medium telephoto to 200mm telephoto when mounted on full-size format SLR cameras and a focal length range from 109mm to 310mm* ultra telephoto when mounted on a DSLR camera with an APS-C sized imager. This "SP" lens uses three "LD" (Low Dispersion) glass elements which effectively compensates for chromatic aberrations providing edge-to-edge sharpness and high contrast image quality with flat-field characteristics over the entire zoom range. With the use of "Internal Surface Coatings" and multiple layer coatings to prevent reflections from the lens surface it is reduced to the absolute minimum. Overall the photographer will enjoy the rich expressive performance of a top rated, lightweight large aperture telephoto lens that will help you capture outstanding telephoto images of majestic scenery, stunning portraits sports, action and more.
This is the magnifying factor of a lens. Macro lenses will often be described by their “magnification factor”. A lens with a 1:1 magnification factor produces a projected image on the sensor which is the same as the subject.
The individual pieces of glass that form the overall optical construction. Most lenses have between four and eleven elements to bend the light rays to ensure a perfectly formed image appears on the light sensitive surface, such as a film or CCD. The elements are arranged in groups and may be seen in specification sheets as, for example, 6 elements in 4 groups. That configuration may have two single elements and the other four grouped in pairs.
A lens with a 1:1 magnification factor produces a projected image on the sensor which is the same as the subject. A 1:1 magnification factor is usually considered the minimum for a lens to be described as a “macro” lens. Specialist macro lenses are often 1:3 or even 1:10 magnification factors, meaning that 1mm across the subject becomes 3mm or 10mm when projected onto the sensor, thus 3 or 10 times magnification.