Saturday, February 25, 2012

Nikkor 18-200mm VRII Lens Review

The purpose of having a DSLR, apart from the fact that it can produce images with stunning quality, is providing its user the ability to change lenses at will. Maybe a wide angle lens for landscape and architectural shots, a portrait lens to capture the cute baby laughing, a telephoto lens for your wildlife and sports shutter bug needs; and not to forget a low light lens, plus a prime or two. But imagine carrying all of those lenses just so that you don't miss a shot any time. (and not to mention changing lenses all the time and risking environmental effects on you camera sensor) You'd probably end up carrying equipment which would totalling to about 20lb in just lens weight. Ouch! Though each lens is unique in its own way, lugging around all that weight can really bog down the whole experience. So what to do instead? Carry one lens which has all the focal range you'll ever need, gives you great optical performance and is reliable - and that my friend is the the AF-S DX Nikkor 18-200mm f/3.5-5.6G ED VR II. This versatile lens for the DX format Nikon DSLR's gives you no reason to switch lenses again. Lets have a look at some of the specs and what the lens has to offer.

Tech Specs
Focal length18-200mm (equivalent to 27-300mm on the DX format)
Maximum aperturef/3.5-5.6
Minimum aperturef/22-36
Lens construction16 elements in 12 groups (with two ED glass and three aspherical lens elements).
Closest focusing distance0.5 m/1.6 ft.
No. of diaphragm blades7 (rounded)
Diameter x length (extension from lens mount)Appproximately 77 x 96.5 mm/3.0 x 3.8 in.
Filter/attachment size72mm
WeightApproximately 565 g/19.9 oz.
Supplied accessories72mm Snap-on Front Lens Cap LC-72, Rear Lens Cap LF-1, Bayonet Hood HB-35, Flexible Lens Pouch CL-1018

A lot of Nikon technology goes into making a great lens, some of which you will find here on the 18-200 are
- The Extra-low Dispersion (ED) elements, helps correct optical color defects like chromatic abberation.
- Internal focusing allows for the movement of the glass elements within the barrel to move in order to focus, leaving the barrel to stay motionless.
- The Silent Wave Motor inside the lens allows for high speed autofocusing and is incredibly quite
- Vibration Reduction ver II, an image stabilization technology minimized blur caused by camera shake. This allows capturing images at 3 to 4 stops lesser shutter speeds.

Color reproduction, contrast and sharpness are pretty good. Here are the MTF charts for this lens. Interpreting these charts can be a bit complicated, but here is a simple way I do it. The red lines represent the contrast reproducibility of the lens and the blue lines represent the lens sharpness. The higher and straighter these lines are on the y-axis the better the quality of the lens. The x-axis represents the distance in mm from the centre of the sensor to the corner. One other titbit I read of some site is that the closer the dotted and solid lines (of the same color) are the better the bokeh performance of the lens (sweet!). Now look at the charts of the lens and see why the lens is so good.

MTF charts for the 18-200mm VR II
The charts are for the lens at its maximum aperture at both the wide and telephoto end, and looking at them I have to say, those are some of the best straight line I have seen for a DX lens which are capable of scraping the empire state(obvious exaggeration, but a little over the top won't hurt). Some vignetting will be seen at the corner of the frame especially when wide open, but its nothing that can't be corrected by using some photo editing tools.

Auto focus speed is pretty darn good. You can go all the way from the minimum focus distance to infinity and back in about 1.5s. With this lens you hardly ever end up focus hunting(unless its really low light situation). Its always spot on while focusing.

Oh yes, not to forget the distortion the lens produces. This lens travels through a hell of a lot of focal range (11.1x zoom), and distortion is a problem at almost all focal lengths. The 18mm setting displays high level of barrel distortion (2.8%), which changes rapidly to pincushion by 24mm, and increases from 35mm to 70mm (peaking at 50mm and 2.3%), before diminishing again towards the telephoto end. Buts this is not to say that the lens in unusable, in fact you wont notice most of this distortion unless you have a lot of straight lines in your shot (architecture, interiors). For almost everything else (unless you are a perfectionist) the distortion is not really a problem. 

Over all a big lens with a lot of glass, and at 565g it is a bit heavy too. Popping this one in front of an entry level DSLR would be a bit odd, but it balances just fine on higher end DX bodies. At 18mm the lens is at is smallest as the barrel is completely retracted, but at 200 mm the barrel is extended to its limit and it is almost twice as longer as it was at 18mm. 

The lens is not completely weather sealed, it has rubber gasket sealing on its mount ring to prevent some atmospheric effects but as the barrel extends and retracts it can lead to some dust creeping into the lens. Though in my usage of the lens (in reasonably safe environments, but both in humid and dusty conditions) I haven't seen any dust or moisture get in. 

I'd say this is a great all-in-one lens, more specifically its the jack of all and the master of none. Just keep in mind that here are a few trade off's you will have to live with in exchange for such versatility.
- The lens is not a fast one. With a maximum aperture of f/3.5-5.6, daytime shooting should work just fine, but low light photography with this lens leaves a lot to be desired. Just hope that your camera's ISO can be cranked up without compromising on image quality.
- Some lenses exhibit creep, i.e. the lens under its own weight changes focal length (the barrel drops or extends from its current position).While some lens don't exhibit this some do. A minor hiccup, but optical quality is not compromised in any sense. The lens has an 18mm lock to keep it from creeping.
- The distortion is gonna be a problem when thinking of architectural shots. Parallel lines are going be wavy and weird at the wide end.
- The bokeh produced by the lens leaves a few things to be desired. The 50mm 1.8 would do a much better job as portrait lens, with spectacular bokeh and sharpness at 1/8th the price.

If you are an armature photographer who need to upgrade to something that's a notch or two above your kit lens, if you are a photographer who wants to reduce you evergrowing lens bag and just carry one all rounder lens (plus maybe a prime), if you are thinking of travel photography and and want to be as light as possible, then look no further. This is the lens for you. If you can afford it, get it. Its sells new for about $900 on amazon and bhphotovideo

Here area  few shots I took over a period of time with the 18-200mm VR II

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