The Nikon AF-S DX Nikkor 18-105mm f/3.5-5.6G ED VR ($399.95 direct) is Nikon's take on a popular lens design?the enhanced kit lens. Most SLRs ship with an 18-55mm f/3.5-5.6 zoom that cuts some corners in its manufacturing quality and optical design in order to keep costs down. This longer zoom design generally comes in at a higher price point, but is well-built, and has better optics, but still retains a rather modest f/3.5-5.6 aperture. The Nikkor 18-105mm doesn't quite offer the zoom range of competing 18-135mm lenses, but it's sharp and priced more reasonably than others in this class, including the Canon EF-S 18-135mm f/3.5-5.6 IS STM.
The lens measures 3.5 by 3 inches (HD) and weighs 14.8 ounces. It uses 67mm front filters, and includes a lens hood. The close focus distance is 1.5 feet at all focal lengths; working that close will allow you to create a shallow depth of field, even with the modest aperture. It is compatible with Nikon DX cameras, but can also be used with full-frame models in a crop mode. Regardless of what body you attach it to, it captures a 35mm-equivalent field of view of 27-157mm. The Vibration Reduction system helps to compensate for camera shake related to handheld shooting; it can be toggled via a switch on the lens barrel, as can the manual and automatic focus settings. The zoom ring occupies most of the barrel, it's textured to enhance your grip when adjusting the focal length. The manual focus ring sits behind it; it's much smaller, and can be a little uncomfortable to adjust. This is a lens that's designed for use with an autofocus camera. Other 18-135mm lenses, including the Sony 18-135mm f/3.5-5.6 and Pentax SMC DA 18-135mm F/3.5-5.6 ED AL (IF) DC WR are designed similarly. The Canon 18-135mm reverses the positions of the zoom and focus ring, which makes manual focus a bit more comfortable.
I used Imatest to check the sharpness of the lens when paired with the Nikon D7100. It exceeded 1,800 lines per picture height, our cutoff for a sharp photo, at all tested apertures and focal lengths. At 18mm f/3.5 the lens managed an impressive 2,506 lines, which increased to 2,860 lines at f/5.6. The edges were a smidge soft, 1,567 lines, at the widest aperture, but they improved to 1,882 lines when stopped down to f/5.6. The knock on performance at 18mm is barrel distortion?the lens records 3.5 percent there, which gives images a slight fisheye look. This can be corrected in software?the distortion slider in Lightroom does the trick?but you'll have to spend a little bit of time post-processing photos in order to get the best images from this lens at its widest angle.
Zooming to 35mm narrows the maximum aperture to f/4.5, but eliminates the barrel distortion. It shows 1 percent pincushion, which makes lines in images curve slightly inward; this isn't as noticeable as the barrel distortion on the wide end. Sharpness is good here as well; 2,714 lines at f/4.5 with decent (1,700 lines) edge performance. Stoping down to f/4.6 boosts the resolution to 2,801 lines. Edges are about the same, even at f/8.
The 70mm setting gives you a maximum aperture of f/5.3 and adds some problematic pincushion distortion?it increases to 2.2 percent. The resolution score here is good, 2,591 lines, but edges soften to 1,454 lines. Overall sharpness dips a bit at f/8, dropping to a reasonable 2,681 lines, but the edges improve to 1,567 lines. We're seeing a pattern here; the center and middle areas of the frame are doing well as you zoom in, but the edges are suffering as a result.
Distortion is about the same, 2 percent, at 105mm, and the sharpness at the maximum f/5.6 aperture is also good?2,558 lines. Edge performance is a little weak here as well at 1,521 lines. Things stay about the same when you stop down to f/8. Despite its issues with edge sharpness?which is often an issue with zooms?the Nikon does an overall better job with sharpness in comparison to the Canon EF-S 18-135mm f/3.5-5.6 IS STM. That lens is sharp at the wide and tele end, but softens a bit at the 50mm setting at its maximum aperture, and also shows edge softness, as well as barrel and pincushion distortion.
Every zoom lens includes some compromises in its design. The Nikon AF-S DX Nikkor 18-105mm f/3.5-5.6G ED VR limits its zoom range compared with similar lenses, but delivers photos with acceptable center-weighted sharpness throughout its range. There's some distortion and the lens isn't sharp edge-to-edge like a good prime or a pro-grade zoom, but photographers who are in the market for this level of optic will be pleased with the results. It can create a shallow depth of field under the right conditions, but will never be a bokeh machine like a fast 50mm prime lens or a 70-200mm telephoto optic. If you're unhappy with the zoom range the 18-55mm kit lens delivers, or simply have the budget to get a better lens with your new D-SLR, this is a worthwhile upgrade, especially when you consider the price. The Nikon 18-105mm is priced at $400, while competing 18-135mm lenses all hover around the $500 mark.
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