Sigma AF 120-300mm f/2.8 APO DG Zoom Lens for Canon (Used)

Large aperture of F2.8 at 300mm focal length and optimized for used with digital SLR cameras
This lens transforms a large-aperture F2.8 300mm lens into a zoom lens that allows you to determine the picture composition you want without having to change your vantage point. It has two SLD (the special low dispersion) glass elements in front group and another element of SLD is being used for rear group for excellent correction of chromatic aberration.

New coating reduces Ghost and Flare
The new multi layer lens coating and lens design reduce flare and ghost, which is a common problem with digital cameras and also creates an optimum color balance through the entire zoom range.

Hyper sonic motor
The AF drive for Sigma SA, Canon and Nikon cameras is equipped with a silent, responsive and high speed HSM , which also provides full-time manual focus function.

Inner Focusing and Inner Zooming
Since focusing and zooming do not change its overall length, this lens is easy to hold and use. In addition, since the front of the lens does not rotate, a circular polarizing filter can be easily attached and use.

Sigma Apo Tele Converters (optional)
High-speed focusing is possible when this lens is used with dedicated APO EX tele-converters (1.4x and 2x). By adding an APO tele-converter, which is sold separately, you can use this lens as a 168-420mm F4 AF tele-zoom lens with a 1.4x tele-converter, or as a 240-600mm F5.6 AF ultra-telephoto zoom lens with a 2x tele-converter. It is also possible to use AE (Automatic Exposure) function, even EX Tele-converters are attached to the lens.

Key Features

• APO - In order to attain the highest quality images, the APO lens has been made using special low-dispersion (SLD) glass and is designed to minimize color aberration.
  
  SIGMA's APO zoom lenses minimize color aberration. As the refractive index of glass depends on the wavelength of light, color aberration occurs when different colors form images at different points. This problem often occurs with telephoto lenses, but the Special Low-Dispersion (SLD) glass and
  
  Extraordinary Low Dispersion (ELD) used in SIGMA's APO lenses helps to compensate for color aberration, thereby allowing them to produce of sharp images.
• CONV. - APO Teleconverter EX
  This lens can be used with the APO Teleconverter EX. It can increase the focal length and will interface with the camera's AE (automatic exposure) function. 
• EX. - EX Lens
  The exterior of this lens is EX-finished to denote the superior build and optical quality, and to enhance its appearance.
  
• HSM. - Hyper-Sonic Motor
  This lens uses a motor driven by ultrasonic waves to provide a quiet, highspeed AF.
  
• IF - Inner Focus
  To ensure stability in focusing, this lens moves the inner lens group or groups without changing the lens' physical length.
• DG - DG Lens
  The most suitable lenses for 35mm film single-lens reflex cameras, as well as for digital SLR cameras. Sigma's development of the DG (Digital) range of lenses has concentrated on the correction of distortion and aberrations. Magnification of chromatic aberration is particularly conspicuous with digital cameras. The optical designs and cutting-edge technology incorporated by Sigma eliminate flare and ghosting from te image sensor and create excellent color balance. Vignetting is minimized whilst marginal illumination is ensured. These high performance lenses are equally suited for digital and analogue cameras.

By Stephen Lang