Nikon 18-200mm f/3.5-5.6G IF-ED VR II DX AF-S Nikkor

SLRgear Review
December 14, 2009
by Andrew Alexander

Nikon updated its popular 18-200mm zoom lens in July of 2009, responding to feedback from its customer base. The lens doesn't appear to have been redesigned, but rather tweaked in small ways. In particular, the new lens uses rounded diaphragm blades to make up the aperture, includes a 'Super Integrated Coating' to reduce flare and ghosting, and adds a zoom lock switch to address persistent issues with zoom creep.

When the lens was first introduced in November of 2005, it quickly became one of Nikon's most popular lenses. The lens is designed to fit the APS-C subframe sensor, and accordingly will produce hard cropping if mounted on a full-frame camera. On a sub-frame camera, the lens produces an effective field of view of 27-300mm. This lens isn't a "constant" lens, in that as you increase the focal length, both the maximum and minimum aperture sizes decrease. The following table reflects the changes as you zoom:

The lens takes 72mm filters, ships with a petal-shaped lens hood, and is available now for around $800.

Sharpness
One of the areas of improvement in the new lens is sharpness, producing slightly better results than the previous version of the lens.

Wide open at 18mm, the lens produces images with a generous sweet spot of sharpness, around 1.5 blur units through the middle of the frame. The sharpness degrades slightly towards the corners, where we note around 2 blur units. Stopping down offers only marginal improvement, both in the corners and the center of the image, until we note maximum sharpness at this focal length at ƒ/8. At this point central sharpness is still sitting at around 1.5 blur units, but the corners are just a hair under 2 blur units.

Mid-range performance is much improved over the previous version of the lens. Between 24 and 70mm, at the widest aperture settings, central sharpness rests at between 1.5 and just under 2 blur units, while corner sharpness (similarly to the previous version of the lens) varies between focal length setting. At 35mm it is particularly noteworthy, showing upwards of 5-6 blur units, but at other focal lengths between 24 and 70mm it's relatively innocuous - around 2-3 blur units. Stopping down to ƒ/8 offers great improvement, taming the corners dramatically, and producing average performance of between 1 and 1.5 blur units. For maximum sharpness I would set this lens to 50mm and ƒ/8.

Telephoto performance at 135mm and 200mm is still the weak point for this lens, but again, it is somewhat improved over the previous version. By these focal lengths the maximum aperture setting is ƒ/5.6, which makes the vibration reduction setting all the more useful. In terms of results, at 135mm we note a small sweet spot of sharpness in the center of the image at around 1.5 blur units, which softens quickly to around 3-4 blur units at the corners. At 200mm this effect is similar but the sweet spot is smaller. Stopping down in both cases produces marginal gains, more so at 135mm than 200mm, but not much.

Fully stopped-down performance isn't bad, producing images with around 2-3 blur units. At 200mm however, we note results in the range of 4 blur units.

Chromatic Aberration
Performance for chromatic aberration is virtually unchanged from the previous version of the lens. On a body with automatic chromatic aberration reduction CA would probably be dramatically reduced, but on our D200 test body, we note fairly high CA results at the wide (18mm) and telephoto (200mm) extremes. At other focal lengths, CA is well-controlled. There isn't much difference between aperture settings at the wide angle, but at 200mm, smaller apertures produce slightly more CA, with the worst results at ƒ/36.

Shading (''Vignetting'')
Results for light falloff appear to be virtually identical between the previous and current versions of the 18-200mm ƒ/3.5-5.6. Corner shading is present but not overly problematic, with the worst results showing at 18mm and ƒ/3.5. Images produced with these settings show corners that are over 3/4 EV darker than the center. To get images with only marginal corner shading, you'll have to stop down to at least ƒ/8, or (interestingly) shoot at 24mm or 35mm, where light falloff doesn't appear to be an issue.

Distortion
The complex array of lens elements that allows such a vast range of focal lengths in one lens leads to some dramatic results for distortion. When used in the wide angle configuration, the lens provides uniform barrel (''bloat'') distortion up to around 21mm, with noteable distortion in the corners at 18mm (+1.2%). After 21mm, distortion across the frame remains consistently barrel-distorted, but at a moderately low level (around 0.25%, on average) and the extreme corner distortion turns into the pincushion (''squeeze'') style. The worst results are seen between 24mm and 50mm, where the corners show -0.75% pincushion distortion.

Autofocus Operation
As an AF-S lens, autofocus operation is quick and virtually silent. The 18-200mm will work on all Nikon camera bodies that support SWM (silent wave motor) lenses. Autofocus results can be overridden at any time by simply turning the focus ring.

Macro
The lens isn't rated for macro, but that said it's not bad either: a magnification of 0.22x (1:4.5 reproduction), and a minimum close-focusing distance of 50cm (just over 18 inches).

Build Quality and Handling
The Nikon 18-200mm ƒ/3.5-5.6 is a built with a durable plastic construction, finished with a matte black texture. The lens mount is metal and the 72mm filter threads are plastic. The lens comes with a petal-shaped hood.

The lens features a switch to disable autofocus (''M/A - M'') and a distance scale marked in feet and meters, located under a clear plastic window. There are no depth of field markings, or an infrared index mark. As a G-series lens, there is no aperture ring. The lens also features seven rounded aperture blades. Two other switches are present, one to enable or disable vibration reduction, and one to select the style of vibration reduction required: active (4-axis) or normal (2-axis, on the horizontal plane).

The zoom ring is the larger of the two, mounted towards the end of the lens. The ring is 3/4-inch wide, made of a tactile rubber, and surfaced with raised ribs. The zoom ring is nicely cammed: it takes two fingers to move the ring. At 200mm, there is significant lens extension, as the lens doubles its length from around 3 1/4'' to just under 6 1/2''. Zoom creep was a widely-reported problem for this lens, more so as the lens aged. Accordingly, Nikon has included a zoom lock switch, which when selected locks the lens to its 18mm position.

The focus ring is plastic, just 3/8'' wide and textured with raised ribs. The ring is mounted closer to the lens mount. The ring takes about ninety degrees to run through the focusing range, but there are no hard stops at infinity or close-focus; rather, there is a slight increase of resistance to let you know you're at the end. There is some additional room at infinity to allow for focusing at different temperatures. The front element does not rotate during focus or zoom operations.

While I can't give you definitive numbers for the VR performance of the 18-200mm (Nikon claims up to four stops of improvement), I can tell you it does offer improved performance in controlling camera shake. The VR employed in the 18-200mm hasn't changed from its predecessor design, offering only one setting for VR (on and off). When set to ''normal'', the system allows for panning shots which compensate for vertical shake only; in ''active'' mode, the system compensates for movement in all four directions.

The petal-shaped lens hood reverses onto the end of the lens for storage; the interior of the hood is a smooth, matte finish.

Alternatives

Nikon 18-200mm ƒ/3.5-5.6G IF-ED AF-S DX VR Nikkor ~$?
Now discontinued, the original 18-200mm is still a capable lens, and perhaps one unintended advantage inherent in the release of version 2 is that used copies of version 1 will now hit the market, and dealers will be selling off copies of their old stock. While technically not as sharp as the newer version, the differences are minor, and in terms of performance in the categories of chromatic aberration, light falloff and distortion, the two lenses are virtually identical.

Sigma 18-250mm ƒ/3.5-6.3 DC OS HSM ~$500
Sigma's offering in this category is comparable in the wide and mid-range of its focal lengths, but after 80mm, the Sigma isn't nearly as capable as the Nikon. Stopped-down though, it's not bad. To its credit, the Sigma offers much less corner shading, though chromatic aberration is more problematic. Results for distortion are almost identical. Sigma also produces an 18-200mm OS lens.

Tamron 18-270mm ƒ/3.5-6.3 Di II VC LD Aspherical IF Macro AF ~$575
Tamron's 18-270mm lens holds the crown (at time of writing) as the travel zoom with the widest range of focal lengths. The Nikon is slightly sharper wide open, but stopped down, the Tamron is just as capable. Results for chromatic aberration are impressively low at wide-angle and in the mid-range, but at telephoto, CA is significantly high. Light falloff is better than the Nikon, but distortion is slightly worse.

Conclusion
Nikon hasn't re-invented the 18-200mm ƒ/3.5-5.6 VR2 (II), but they've made some useful tweaks, addressing some complaints that have dogged this lens since it was first introduced. For its size and price point, it makes an excellent all-in-one lens.

Sample Photos

The VFA target should give you a good idea of sharpness in the center and corners, as well as some idea of the extent of barrel or pincushion distortion and chromatic aberration, while the Still Life subject may help in judging contrast and color. We shoot both images using the default JPEG settings and manual white balance of our test bodies, so the images should be quite consistent from lens to lens.

Still Life shot

VFA target

As appropriate, we shoot these with both full-frame and sub-frame bodies, at a range of focal lengths, and at both maximum aperture and ƒ/8. For the ''VFA'' target (the viewfinder accuracy target from Imaging Resource), we also provide sample crops from the center and upper-left corner of each shot, so you can quickly get a sense of relative sharpness, without having to download and inspect the full-res images. To avoid space limitations with the layout of our review pages, indexes to the test shots launch in separate windows.