PCPhoto
Go Wide!Add extra visual excitement to your portraits, scenics and more with the extreme perspective of wide-angle lenses |
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Page 3 of 4 Extreme-Range Wide Zooms For photographers on tight budgets or those who want to travel light, an extreme-range zoom is an excellent option, since it provides focal lengths from true wide-angle to true telephoto in a single, often compact package. Fixed-focal-length wide-angle and telephoto lenses are available with much faster maximum apertures, and less barrel and pincushion distortion—at somewhat greater bulk and cost—but today’s extreme-range zooms are terrific options for those who want one lens that can “do it all.” The first extreme-range zooms for film SLRs were 28-200mm models (Canon offered a 35-350mm for its EOS cameras), followed by 28-300mm versions. The main drawback to these for users of small-sensor D-SLRs is that the 28mm focal length effectively becomes 42-45mm—no longer wide-angle. To solve this problem, several manufacturers now offer extreme-range zooms that start at 18mm, so they really do go from wide-angle to super-telephoto on small-sensor D-SLRs.  Nikon’s 18-135mm ƒ/3.5-5.6G ED-IF AF-S DX Zoom-Nikkor was designed specifically for the APS-C sensors used in all Nikon D-SLRs, and is equivalent to a 28-200mm zoom on a 35mm SLR.  Nikon, Sigma, Sony and Tamron all offer 18-200mm zooms (equivalent to 28-300mm on a 35mm camera), and Tamron has the AF18-250mm ƒ/3.5-6.3 Di II LD Aspherical (IF), which is equivalent to a 28-375mm on a 35mm camera, an amazing 13.9:1 zoom ratio. The Nikon lens can be used on Nikon and Fujifilm D-SLRs, the Sony on Sony and discontinued Konica Minolta Maxxum D-SLRs. The Sigma and Tamron offerings come in mounts for Canon EOS, Nikon/Fujifilm, Pentax/Samsung and Sony/Maxxum D-SLRs.  Sigma also offers a stabilized (OS) 18-200mm. Note that none of these lenses can be used on a full-frame D-SLR or a 35mm SLR; they were designed for the smaller image sensor and won’t cover a full 35mm image frame and, in some cases, there are also mechanical incompatibilities. Things to Consider Lens speed at the longest focal length. With most extreme-range zooms, the maximum aperture at the shortest focal length is more than a stop faster than the maximum aperture at the longest focal length. Autofocus performance falls off as lens speed decreases. So, if you do a lot of action photography, especially in dimmer light, you’ll be better off with a 70-200mm ƒ/2.8 or even a 55-200mm ƒ/4.5-5.6, and a separate 18-55mm or 18-70mm zoom for the wide-angle work, rather than with a 18-200mm ƒ/3.5-6.3. Minimum focusing distance. If you like to shoot close-ups, note the close-up capabilities of the lenses you’re considering. Some extreme-range zooms will focus much closer than others, and some will focus close only at one focal length (or a limited range of focal lengths), while others will focus close throughout the range. Some will focus continuously from infinity to their minimum focusing distance, while others require that you enter a special macro mode to focus at close range. Consider the lens’ maximum magnification as well as its minimum focusing distance: One manufacturer’s 70-300mm zoom produces a 1:2 (half life-size) reproduction ratio at its minimum focusing distance of 37.4 inches at 300mm, while the same company’s internal-focusing 18-250mm zoom produces a 1:3.5 (just over quarter life-size) reproduction ratio at its minimum focusing distance of 17.7 inches at 250mm. In other words, the 18-250mm zoom provides 83 percent of the focal length and focuses twice as close, but produces barely over half the magnification of the 70-300mm. Sometimes being able to focus closer is more important; other times, getting the largest image size in the frame is more important. Be sure to get a lens that suits your needs.   |
