Sigma 28-135mm F3.8-5.6 Aspherical If Macro Is One Of Several Lenses Introduced At Pma 2000 By Sigma Corporation. Incorporating Aspherical Optics, Plus A Floating Inner Focusing System, This Lens Minimizes Spherical Aberration And Stigmatism. This Lens Can Focus From Infinity To 19.7 At All Of The Focal Lengths Without Close-up Accessory, And As Close As 9.4 (1:2 Reproduction Ratio) At The 135mm Zoom Position. This Lens Incorporates An Inner Focusing System And Features A Non-rotating Front Lens Barrel For Convenient Filter Use. A Custom Designed perfect Hood With Bayonet Mount Is Provided To Prevent Extraneous Light From Degrading The Image Quality.