Sigma 24-70mm f/2.8 EX DG MACRO is a large aperture standard zoom lens provides superior performance both for Digital SLR Cameras and 35mm Film SLR Cameras.

To achieve an F/2.8 aperture at all focal lengths, it employs three aspherical Lens to provide optimum aberration compensation.   Two Special Low Dispersion (SLD) glass elements are provided for color aberration compensation, to assure high image quality.

Optimized for digital SLR cameras
It incorporates "Super Multi Layer Coating" to reduce the influence of harmful light caused by reflections from the digital image sensor.

Excellent correction of aberrations
Two⁽²⁾ SLD elements, one Glass Mold Aspherical plus two⁽²⁾ Hybrid Aspherical lenses provide excellent correction of various aberrations and a high level of optical performance.

Recorded Known Strengths

• Finishing is Good, Strong, durable. Some people don't like the flat matte finish, but it offers a more solid grip surface than a polished surface
• Fast, accurate operation. Screw focus goes from closest to infinity very quickly
• Lens is not prone to hunting or AFC dancing, even in low light
• sharpness from f/3.5 and upwards (indeed very soft at f/2.8, but DOF is really minimal than too) Good sharp pictures from f/4 and up
• Not really cheap, but more affordable than inferior counterparts, especially OEM
• AF sound does not trouble me at all, it might be 'loud' for some users, but i honestly did not even notice
• The focus ring just works - It's large, and very comfortable to use

Reported Weaknesses

• This is no weenie, it has a filter size of 82mm
• Prone to camera and mirror slap shake at lower shutter speeds
• Zoom creep - only at extreme ups and downs
• soft at f/2.8
• The zoom ring also tends to be a bit hard to use due to stiffness, many have found that with use the stiffness loosens to a more comfortable degree

Closest Counterpart
The nearest counterpart of Sigma 24-70mm f/2.8 EX DG MACRO would be a Tamron AF28-75mm f/2.8 XR Di LD Aspherical (IF), based on range and aperture with a smaller 67mm filter size.   Retails around $ 377.99 US dollar.

Specification

• Lens Construction : 13 Elements in 14 Groups
• Angle of View : 84.1 -34.3 degrees
• Number of Diaphragm Blades : 9 Blades
• Minimum Aperture : F32
• Minimum Focusing Distance : 40cm / 15.7 in.
• Maximum Magnification : 1:3.8
• Filter Size : 82mm
• Dimensions : Diameter 88.7mm x Length 115.5mm 3.5 in. x 4.5 in.
• Corresponding AF Mounts : Canon, Nikon(D), Sigma, Pentax, Sony/Minolta(D)

The retail price of this Sigma 24-70mm f/2.8 EX DG MACRO is around $ 400.00 US dollars and have been rated 3.84 out of 5.0.