Nikon's 17-55mm lens is designed for Nikon DX (APS-C) sized sensors. With a fast continuous aperture of f/2.8...
Within the 10 groups of 14 elements are aspheric lenses and three Extra low Dispersion optics, to reduce chromatic aberration and increase resolution and contrast. The DX marking also gives away the focal length shift, in this case a 1.5x magnification, lifting the lens to a 25.5-82.5mm equivalent. Another reason for the optic’s weight is the solid metal construction; this lens has a tacitly solid feel, instilling confidence that it can tackle extreme conditions. At the widest length the front element extracts about half an inch from the outer barrel, though focusing is internal, leaving room for filters and, with no rotation, it can be used with polarisers. The focus and zoom grips are secure, with just enough resistance to stop them feeling loose, but not enough to feel tight. The SWM is effective, but on the D80 – used in this test – is noticeably slower than that of the Canon equivalent.
The Nikon optic maintains high resolution throughout the aperture range at 17mm, matching the Canon 17-40mm f/4.0 L USM lens, but fails to match it at 55mm. However, it’s a consistent performer, and its centre to corner fall-off is well controlled. In terms of chromatic aberration it displays slight fringing, but this is rarely visible except in extreme contrast conditions, and is more obvious in corner areas. In the lab, this lens displayed one of the best CA test results.