You can get the focal length of the Tokina AT-X 17 AF Pro lens in a zoom, and sometimes in a similar focal length, so why bother with a single focal length? The answer has two parts: size and quality for the price. The Tokina 17mm ƒ/3.5 lens lists for $810 and has a street price of approximately $400. Zoom lenses that get this wide and are close to this price usually aren't as sharp as the Tokina in the wider ƒ-stops (stopped down, modern lenses of any major manufacturer at any price are quite remarkable), don't control flare as well, and exhibit some barrel distortion (bending of straight lines, such as horizons, when near the edge of the frame). After shooting with the AT-X Pro for a while, I found it consistently sharp throughout the ƒ-stop range, with a high degree of flare control, and straight lines stayed straight.
Expensive zooms that reach this focal length easily will match the image quality of the AT-X 17mm or any other single-focal-length lens. However, there's a price to pay for them—they can be three or more times the cost, plus they're much bigger lenses, both in height and width as well as weight.
I'd have no problems recommending this lens to anyone who needs a super-wide-angle for 35mm or a strong wide-angle for a small-format digital SLR (e.g., for a 1.5x magnification factor, the lens is the equivalent of a 25mm). The lens is rugged and well built, and includes a quick-change ring for switching from auto to manual focus. Filters are 77mm, and the front of the lens doesn't rotate for focus.
1 Ideal wide-angle for small-format digital SLRs because of price and quality
2 Sharper and with fewer lens distortions compared to lower-priced zooms with this focal length
3 Internal focusing—front of the lens doesn't rotate
Tokina 17mm Wide-Angle
I'd have no problems recommending this lens to anyone who needs a super-wide-angle for 35mm or a strong wide-angle for a small-format digital SLR (e.g., for a 1.5x magnification factor, the lens is the equivalent of a 25mm). The lens is rugged and well built, and includes a quick-change ring for switching from auto to manual focus. Filters are 77mm, and the front of the lens doesn't rotate for focus.
Contact: THK Photo Products, Inc., (800) 421-1141, www.thkphoto.com.