The Sigma AF 28-300 mm f// 3.5-6.3 Compact Aspherical IF Hyperzoom is one of the first all-purpose hyper zoom Sigma lenses for SLR cameras of major autofocus systems.
In order to increase focusing speed and accuracy a multifingered mechanism is used, which enables several optical components to move simultaneously.
Due to the internal focusing system, the front lens does not rotate, which enables the use of polarized and other filters.
In order to prevent spontaneous extension of the barrel the zoom lock is used to fix the lens at the position of 28 mm.
There were variants produced for Canon, Nikon, Sigma, Pentax, Minolta.
Posted by: Flicker Date of publication: 27.10.2011