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An ultra-telephoto zoom lens covering a telephoto range up to 500mm, incorporating Sigma’s original OS (Optical Stabilizer) function.

The Sigma Corporation is pleased to announce the launch of the new APO 150-500mm F5-6.3 DG OS HSM.

This ultra-telephoto zoom lens covers a telephoto range up to 500mm and allows photographers to bring the subject close and short perspective. Sigma’s original OS (Optical Stabilizer) function offers the use of shutter speeds approximately 4 stops slower. It is ideal for sports, wildlife and landscape photography with handheld shooting. Three SLD (Special Low Dispersion) glass elements provide excellent correction for
There are two types of chromatic aberration: \"axial chromatic aberration,\" where the focal point position on the optical axis varies according to the wavelength, and \"chromatic difference of magnification,\" where the image magnification in peripheral areas varies according to the wavelength. In actual photographs, axial chromatic aberration appears as color blur or flare, and chromatic difference of magnification appears as color fringing (where edges show color along their borders). Chromatic aberration in a photographic lens is corrected by combining different types of optical glass having different refraction and dispersion characteristics. Since the effect of chromatic aberration increases at longer focal lengths, precise chromatic aberration correction is particularly important in super-telephoto lenses for good image sharpness.

Although there is a limit to the degree of correction possible with optical glass, significant performance improvements can be achieved using man-made crystal such as fluorite or UD glass. Axial chromatic aberration is also sometimes referred to as \"longitudinal chromatic aberration\" (since it occurs longitudinally with respect to the optical axis), and chromatic difference of magnification can be referred to as \"lateral chromatic aberration\" (since it occurs laterally with respect to the optical axis).
Note: While chromatic aberration is most noticeable when using color film, it affects black-and-white images as well, appearing as a reduction in sharpness.', CAPTION, 'Chromatic aberration',BELOW,RIGHT, WIDTH, 400, FGCOLOR, '#CCCCFF', BGCOLOR, '#333399', TEXTCOLOR, '#000000', CAPCOLOR, '#FFFFFF', OFFSETX, 10, OFFSETY, 10);" onmouseout="return nd();">Chromatic aberration. This lens is equipped with a rear focus system that minimizes fluctuation of
1. A point would be formed as a point.
2. A plane (such as a wall) perpendicular to the optical axis would be formed as a plane.
3. The image formed by the lens would have the same shape as the subject.

Also, from the standpoint of image expression, a lens should exhibit true color reproduction. If only light rays entering the lens close to the optical axis are used and the light is monochromatic (one specific wavelength), it is possible to realize virtually ideal lens performance. With real photographic lenses, however, where a large aperture is used to obtain sufficient brightness and the lens must converge light not only from near the optical axis but from all areas of the image, it is extremely difficult to satisfy the above-mentioned ideal conditions due to the existence of the following obstructive factors:

* Since most lenses are constructed solely of lens elements with spherical surfaces, light rays from a single subject point are not formed in the image as a perfect point. (A problem unavoidable with spherical surfaces.)
* The focal point position differs for different types (i.e., different wavelengths) of light.
* There are many requirements related to changes in angle of view (especially with wide-angle, zoom and telephoto lenses).

The general term used to describe the difference between an ideal image and the actual image affected by the above factors is \"aberration.\" Thus, to design a high-performance lens, aberration must be extremely small, with the ultimate objective being to obtain an image as close as possible to the ideal image. Aberration can be broadly divided into two classifications: chromatic aberrations, which occur due to differences in wavelength, and monochromatic aberrations, which occur even for a single wavelength.', CAPTION, 'Aberration',BELOW,RIGHT, WIDTH, 400, FGCOLOR, '#CCCCFF', BGCOLOR, '#333399', TEXTCOLOR, '#000000', CAPCOLOR, '#FFFFFF', OFFSETX, 10, OFFSETY, 10);" onmouseout="return nd();">Aberration caused by focusing. The super multi-layer lens Coating reduces flare and ghosting. High image quality is assured throughout the entire zoom range. This lens incorporates HSM (Hyper Sonic Motor), which ensures a quiet and high-speed AF as well as Full-time manual focusing capability. The addition of the (optional) 1.4x EX DG APO or 2x EX DG APO Tele Converters produce a 210-700mm F7-9 MF ultra-telephoto zoom lens or a 300-1000mm F10-13 MF ultra-telephoto zoom lens respectively. A removable tripod socket (TS-31) is included as a standard component.

• Incorporating Sigma’s original OS (Optical Stabilizer) function.
• An ultra-telephoto zoom lens covers a telephoto range up to 500mm and allows short perspective.
• Three SLD glass elements and a rear focus system provide optimum image quality throughout the entire zoom range.
• Super multi-layer coating reduces flare and ghosting.
• HSM ensures quiet and high-speed autofocus.