Glass act
Nikon has updated its compact-sized, DX-format 18-200mm zoom lens. David Kilpatrick finds that you get what you pay for
Nikon has always made an effort to 'future proof' its SLR systems, and where possible, successive new generations of lenses are designed so that they can be used with both vintage and modern cameras. Inevitably, new technologies make some older kit obsolescent, but so far it's been fairly smooth progress.
The new AF-S Nikkor DX 18-200mm f/3.5-5.6 GII ED VR is generation two of the same focal length zoom launched in 2006, and like that lens it retains the full 10-pin contact array of classic AF-S optics. Given that all Nikon DX-format bodies today only have eight contacts, I wonder if there's some old Kodak or Nikon gear out there from the pioneering decade of digital that can now use this latest zoom?
In some other lenses, such as the AF-S G 18-55mm VR, only eight contacts are used. I can't help wonder whether the surviving ten-contact specification of fully compatible AF-S lenses might not be used in future to improve things such as continuous live focusing during video filming.
Steady load
The lens is identified as 'VRII' on Nikon's website and even in the lens instruction leaflet - as if the 'II' was connected to the vibration reduction. Yet the earlier lens of similar specifications already had 'VRII', introduced in 2006 to go with the D200/D80 camera generation. This lens has the II written after the letter G on the barrel not after the VR.
VRII stabilisation offers up to four steps of steadying effect compared to three with the standard VR, and offers the choice of Normal (photographer standing still) or Active (photo-grapher being driven in the back of a donkey-cart) modes. 'Active' must not be mistaken for a mode to be used on moving subjects! The Normal mode is better for action panning, but even better still is the Off position for VR.
For fun I tried some slow-speed pans (0.25s sort of exposures on racing horses) and leaving the VR switch on in any mode does little but mess up the result. It was a very windy spell during testing, and in buffeting winds the Active VR mode helps. As for the four steps versus three steps claim, in my experience different photographers have hand-holding abilities a shutter speed or three apart.
One thing is certain, the new lens shows very little degradation of sharpness when VR is active, and never produced any un- expected vignetting. Both effects can be seen in earlier Nikon VR lenses. The optical design appears very similar to the 2006 18-200mm, with a little more barrel distortion at 18mm but better retention of sharpness to 200mm and particularly good flatness of field across the entire range for close-ups down to 0.5m.
The close focus is adequate but not extreme in so-called macro range, about a quarter life-size at 200mm. Working distance is well maintained, with very little reduction in true focal length caused by the internal focusing. The size of the lens does mean that whether shooting wide-angle groups or tele close-ups the built-in flash will cast a shadow, minimised by removing the bayonet petal lens hood. It uses 72mm filters (non-rotating front rim) and nothing much less would be expected given the fast maximum aperture of f/5.6 at the long end. Most such superzooms (Sigma, Tamron) are only f/6.3, though Canon's competitor is also a chunky f/5.6 model.
Pros and cons
In use, the resolution achieved on the Nikon D5000 (a very sharp 12.3 million pixel camera, as is the D300S) was a surprise. The results are in a class above any I've had from similar range lenses on APS-C at 12 million pixels before, and that includes the Sigma 18-250mm OS, which I rate highly.
Where the Sigma has correctable chromatic fringes at longer lengths, the Nikon 18-200mm produces a very clean image across the entire range except for 18-22mm where around -20 Red/Cyan CA removal is needed when processing with Adobe Camera Raw. No visible loss of resolution sets in at the long end (as normally happens with zooms over 10x) and no CA correction was needed from raw. The long end was also sharper than wide-angle shots, though even f/3.5 was usable at 18mm.
Later Nikon bodies will auto-correct distortion and vignetting in JPEGs, and it was interesting to line up a JPEG next to a raw in Adobe Bridge and flick between the large previews. The image snaps into its correct geometry, and you can also see that a little angular coverage always ends up being lost. It's not possible to correct distortion without enlarging and cropping either the diagonal (for pincushion, long end) or horizontal-vertical (barrel, wide end) coverage. It is too subtle an effect to show on the printed page but clear enough on your computer screen. The barrel distortion at 18mm is sudden neutral at 20mm, then turns to pincushion at 22mm, gets most severe from 30mm to 100mm, and gradually returns to almost zero at 200mm.
The new lens has one big, and very welcome, improvement - a zoom lock. Like all the other zoom locks around, this one is limited to fixing the lens at 18mm. I would hope Nikon could be the first the break this restriction. When you have the lens at a set length such as 50mm, and need to aim up or down, it's still not possible to prevent zoom creep. What is needed is a zoom lock that operates by friction at all focal length settings, and by a notch at 18mm for storage. The lock is even marked with '18' to tell you. It's a borrowing from generations of Sigmas and Tamrons, which have had wide-end locks to combat tromboning barrels, when something far more useful was possible.
Since the new lens is only 5g heavier than the 2006 model, and looks almost identical right down to the VRII double controls and most of the designated name, you may be offered existing stock original VR models. The quick way to spot the difference is that the earlier model has a red VR label, the new one has gold; the old one says G, the new one says GII.
The original 18-200mm is said to have a history of more failure, or servicing needed, to its AF-S focusing mechanism than other similar Nikkors. It's likely that both the AF-S and VR mechanisms of the new lens are improved for reliability as well as performance.
Conclusions
The 18-200mm is a logical upgrade for anyone using an 18-55mm kit lens, and provides a single lens solution for inter- national travel. The 200mm focal length may avoid the attention of curators and concert security staff, including those who refuse admission to larger 'white lens' gear even if that's only extending to 200mm. The size is so much more compact, when collapsed and with the lens hood reversed or pocketed, you should not be challenged when equipped with it.
As the sharpness, illumination, geometry, out-of-focus image quality and flatness of field are all well above expectations for a superzoom it can be recommend-ed for professional portraiture, groups, PR work, weddings and similar jobs. It also seems to have sharpness in reserve for higher resolution DX sensors when Nikon moves beyond 12 million pixels.
Freedom from flare is good. It was possible to induce some with the sun just outside the frame, but sunsets and other light sources included in the shot produced minimal or no visible reflections.
At the time of writing, no kit deals have been spotted with the new 18-200mm but there were few offers with the original version. It is not cheap, with an official retail close the £1000 mark and a street price around £700 when the superseded model is around £200 less. That is the price paid for top optical quality and the best current form of Nikon VR.
