Nikkor DX 18-200mm VR II coverage and stabilisation The Nikkor DX 18-200mm VR II is designed as a powerful all-round lens with an 11.1x super-zoom range. With the 1.5x field-reduction factor of Nikon's DX-format DSLRs, the DX 18-200mm VR II delivers equivalent coverage of 27-300mm, taking you from wide angle all the way to pretty respectable telephoto coverage. To illustrate this significant range in practice we mounted the lens on a DX-format body, attached it to a tripod and shot the same scene fully zoomed-out, then fully zoomed-in.
It’s clear from the images above the degree of flexibility such a lens provides. You could be shooting an expansive landscape at one moment, spot an unusual bird or animal in the distance and within a second or two twist the zoom ring around to capture a tight close-up view. Such a range is equally useful when shooting in urban environments, allowing you to capture wide architectural views, before zooming-in for some interesting street shots. Suffice it to say the ability to zoom from wide to decent telephoto is also ideal when you’re attending weddings or sporting events. Of course you can achieve the same range with multiple lenses, and also generally enjoy superior performance while you’re at it, but the convenience of having it all in one lens cannot be underestimated. You don’t need to lug multiple lenses around with you, waste time changing them while running the risk of missing your photo opportunity, and of course by not removing lenses, you’ll also minimise the risk of dust entering the body. All these reasons make super-zooms ideal for travel photography, and are responsible for them topping the best-sellers lists. If you're upgrading to the DX 18-200mm VR II from a typical Nikkor kit lens, the wide angle coverage will be essentially the same when zoomed-out, but of course the big difference is when you're zoomed-in. To illustrate the difference you can expect in practice we've taken photos with the DX 18-55mm VR and DX 18-105mm VR kit lenses when each is fully zoomed-in, then superimposed a frame indicating the relative coverage of the DX 18-200mm VR II when it's zoomed all the way in. To generate these frames, we superimposed actual images taken with the DX 18-200mm VR II and reduced their size until the details matched. As such, the images below illustrate the exact differences you'll experience.
As seen above left, DX 18-200mm VR II can capture a significantly smaller area than the DX 18-55mm VR kit lens, and represents a big step-up in power over that model. The difference with the DX 18-105mm VR above right though may not seem as great as you perhaps expected, and it's even less so when compared against the older DX 18-135mm kit lens. It still represents a healthy boost in magnification, but owners of these lenses may prefer complementing them with the AF-S 70-300mm VR for greater power. When discussing optical ranges, especially on super-zoom models, it's also important to consider the focusing distance. Lenses that employ internal focusing systems can suffer from an optical effect known as shrinkage, where the effective focal length actually decreases at closer focusing distances. This effect applies more for zoom lenses and particularly those with long zoom ranges. This is why all manufacturers calculate and quote focal lengths with the lenses focused at infinity, as the range could actually be noticeably lower when focused on closer subjects. We've previously discussed the effect of zoom shrinkage in this article, while our forum moderator Thomas delved into the technicalities in this forum post, but for the first time we're now going to illustrate the impact in one of our reviews. Below are the coverage shots you saw earlier with the lens focused at infinity. This time we've superimposed the image taken at 200mm over the one taken at 18mm and shrunk it until the details matched. We then used this to create a frame to indicate the relative coverage. So the red frame you see below left indicates the area captured by the lens when zoomed-into 200mm. If you were to place similar frames corner-to-corner, you'd find the effective range was close to the 11.1x as expected.
So far so good, but now let's see what happens at the closest focusing distance of 50cm. As before we took two photos from the same tripod-mounted position, first at 18mm, and secondly at 200mm. Once again we superimposed the 200mm image over the 18mm version and shrunk it until the details lined-up; this was then used to generate the green frame you see below left.
If you've not come across this effect before, you'll probably be suprised at this point, but as mentioned at the start, it affects all lenses with internal focusing, especially zooms, and particularly those with super-zoom ranges. It's not just Nikon or this lens. Some optical designs suffer more than others, but it's an issue which faces most zooms. By sharing the same optical construction as its predecessor, the zoom shrinkage of the DX 18-200mm VR II is no worse, but as illustrated above, it's certainly noticeable and will impact anyone who shoots subjects at close range, such as portraits and especially macro images.
Nikkor DX 18-200mm VR II Stabilisation
VR is enabled by flicking a switch on the side of the lens barrel. Nikon claims the lens has four stops of compensation and like many VR models there's the choice of Normal or Active modes, the latter designed for photographing from a moving vehicle. To put its effectiveness to the test we took a series of photos with it zoomed-into an equivalent of 300mm, where traditional photographic advice would recommend a shutter speed of at least 1/300 to eliminate camera shake. Our sequence started at 1/320 and reduced by one stop each time until 1/10. We performed this sequence twice, first without VR enabled, and secondly with VR enabled. Below are 100% crops taken from the non-VR and VR images at a shutter speed of 1/20.
On the conditions of the day, the fastest we could handhold a sharp result when fully zoomed-in without any stabilisation was at 1/320; anything slower suffered from camera shake. With VR enabled, we could match the sharpness under the same conditions at a shutter speed of 1/40, although the result at 1/20 was almost as good. You can see examples taken at 1/20 with and without stabilisation above, and it’s clear how the version with VR is much steadier. This corresponds to between three and four stops over our 1/320 shot in practice, which just about meets Nikon's claim of four stops of compensation. It's certainly a very useful facility to have at your disposal and makes handholding the DX 18-200mm VR II quite possible even at its longest focal length in modest to low light. |
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