This particular lens offers a 4.1X zoom range, a 26-107mm equivalent in full frame. It has two hybrid aspherical (AL) elements, which deter most chromatic aberration. Although the 17-70 is not a DA star lens (DA*), which is Pentax’s premium lens series, it has some of the premium features like the Pentax Super Protect (SP) lens coating to repel dust, moisture and grease. Seems well made, almost like a pro lens, not at all plastic-feeling, but, sorry, no special seals to keep out dust and moisture. It also has Pentax’s Supersonic Drive Motor (SDM),which the company claims makes for smoother and quieter autofocus operation. It’s the only no-DA* lens right now in Pentax’s lineup that has SDM. Unfortunately, in the lens that we tested, the SDM didn’t seem to be as quiet as Canon’s USM or Nikon’s SWM systems–we heard a low whiny sound as we autofocused.