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Aspherical lenses. Lens elements that are not spherical can reduce the total number of elements required in a lens design. They can deliver better performance while reducing weight and size.

Aspherical lenses maximize optical performance while minimizing lens size and weight. Aspherical lenses help reduce some of the problems usually associated with wide angles and zooms, such as lens flare and edge distortion.
They also help deliver higher quality telephoto images.


APO lenses. These lenses use apochromatic design and Special Low Dispersion glass (SLD) for minimum color aberration and ultimate telephoto image quality, improving contrast and sharpness.

Apochromatic (APO) telephoto lenses greatly minimize color aberration, a phenomenon created by different wave lengths of light refracting at different angles. This causes each color to have a slightly different imaging point, resulting in poor image quality.

APO Zoom Macros offer up to 1:2 magnification in the telephoto range with instant shifting from normal to macro shooting.

APO Tele-Macros offer 1:3 image size close focus, long thought to be impossible for a telephoto lens — and are no larger than a fixed focal lens of the same class.


Internal and Rear Focusing. Conventional automatic focusing is done by moving either the entire lens system or just moving the front lens group.

For our telephoto and telemacro lenses, Sigma developed an internal focusing system that moves lens groups inside the lens barrel, significantly improving macro capabilities. For super wide-angle lenses with large front diameters, we created a rear focusing system that moves only the rear lens group.

For our mid-range lenses, we use an internal focusing system that moves inner lens groups to allow a shorter minimum focusing distance. All while retaining a constant physical lens barrel length.


HyperSonic Motor. Enables virtually silent, highly responsive auto and manual focusing, as well as manual focus only override.

UC
Ultra Compact. The smallest, lightest lens of its type available.

DL
Deluxe. DL lenses are full feature lenses in spite of their modest price. Like other Sigma lenses, they are supplied with a custom lens hood and feature half-stop increments on manual aperture settings, depth of field scale, distance scale, infrared correction mark.

DF
Dual Focus. It is easy to hold the lens, since the focusing ring does not rotate during auto-focusing and yet provides adequate focusing torque of the focusing ring during manual focusing of the lens.

HF
Helical focus. This system of the lens eliminates front lens rotation, thus allowing the use of a Perfect Hood and easy to use polarizing filters.


Excellence. These professional type lenses feature the distinctive EX finish and EX logo on the lens barrel.