Sigma's 8-16mm f/4.5-5.6 DC HSM Wide-Angle Zoom Lens
When it comes to wide-angle zooms, you have wide zooms, ultra-wide zooms and then you have Sigma's 8-16mm/f4.5-5.6 DC HSM, which with an angle-of-view range of 75.5° to 114.5° is the flat-out champ in its class. It's also quite responsive, feels really nice in your hand, is pleasingly sharp. Even at 8mm, it remains respectfully rectilinear when squared off to your subject.
Designed for use with compact (APS-C format) DSLRs, the Sigma 8-16mm ultra-wide zoom is available in Nikon, Canon, Sony/Minolta AF and Pentax lens mounts, and contains 15 FLD (fluorite) elements in 11 groups that include a hybrid aspheric lens and two glass molded elements to aid in controlling color aberrations, distortion and astigmatism. Flair and ghosting are kept in check by the Super Multi-Layer Coatings, and smooth focusing is availed by an inner-focusing system that's supported by Sigma's HSM (High Speed Motors) focusing technology.
The primary thing that strikes you the first time you look through Sigma's 8-16mm/f4.5-5.6 DC HSM is that even at the "long" end of the zoom range, it's pretty darn wide. Twist the zoom ring to the wide end of the zoom range and it's hard to stifle the "ooooh" sound that bubbles up from within. Equivalent to a 12-24mm zoom on a full-frame 35mmDSLR, this is the kind of lens that makes shooting in tight quarters a walk in the park. It also happens to be darn good for photographing parks, which in this case was New York City's very own—and very photogenic—Governor's Island.
As I had suspected when packing my bag for the day, the insanely wide focal range of Sigma's 8-16mm zoom came in quite handy both indoors and out. The advantages of shooting landscapes with an ultra-wide lens (zoom or otherwise) is a given, but inside the many restored (and partially restored) officers' residences and other military structures is where I really began to appreciate this lens's ability to define tight quarters. A close minimum focusing distance of 9.4" (24 cm) also enabled me to give what would otherwise be minor architectural details, i.e. doorknobs and stairway banisters, "starring roles" in my single-frame mini-dramas. And after watching two other shooters try in vain to capture murals that covered three walls of a small sitting room, I was able to back myself into a corner and nail the shot from not one, but three points of view.
A big issue concerning ultra-wide lenses when used with digital cameras is the question of sharpness, particularly toward the edges of the frame, when off-axis light strikes the sensor's pixels from increasingly sharper angles. In this area, the lens sample Sigma 8-16mm I used in this test scored higher than I had imagined. When shooting wide open—most noticeably at closer distances—the edges began displaying chromatic aberrations and other signs of digital chaos, but once stopped down to about f/8, the Sigma 8-16mm DC HSM performed admirably.
The Sigma 8-16mm/4.5-5.6 is well finished and features separate zoom and focus rings, both of which felt tight and performed smoothly (though the focus ring was a tad noisy compared to the near-silent zoom ring). The front element is fish bowl shaped, and as such, you cannot use filters with this lens. A built-in tulip-style shade does double duty serving as a flair-blocker as well as your only line of defense against dust and evil things that try to scuff your lens coatings. Needless to say, keep the lens cap on when you're not using this lens.