Camera Accessories

The AF-S DX Nikkor 18-200mm f/3.5-5.6 G ED VR II is a minor redesign of a previous lens. It features a new zoom mechanism for reducing zoom creep (the lens slides forward when tilted). A new zoom lock switch has been added and the multi-layer Super Integrated Coating (SIC) has been improved to provide better image quality and contrast. Otherwise, it's identical to the original Nikkor 18-200mm VR lens.

Side view of the AF-S DX Nikkor 18-200mm f/3.5-5.6 G ED VR II. (Source: Nikon.)

Like its predecessor, this lens is designed as an all-in-one lens for cameras with APS-C-sized imagers. It provides a focal length range equivalent to 28-300mm on a 35mm camera on the Nikon D300S we used for this review. This is equivalent to an 11x zoom range, which is a big ask for any optical system and one reason why this lens is relatively slow.

However, this has enabled Nikon to make this lens relatively compact, with a barrel length of only 96.5mm in at the 18mm setting and a diameter of 77mm (without the lens hood attached). Zooming out to 200mm extends the lens barrel by roughly 65mm. Overall weight is approximately 565 grams. 

Internal focusing means the front element doesn't rotate during zooming, allowing angle-critical attachments to be used without requiring re-adjustment. Autofocusing is driven ultrasonically by a Silent Wave Motor, which is fast and barely audible in operation.

The above diagram shows the internal structure of the lens and the position of the exotic glass elements. (Source: Nikon.)

The optical design comprises 16 elements in 12 groups and includes three aspherical elements plus two ED (Extra-low Dispersion) elements. The front of the lens is threaded to accept 72mm diameter filters. A seven-bladed diaphragm closes to a circular aperture for attractive bokeh.

The closest focusing distance is 50 cm at all focal lengths, which provides a maximum magnification ratio of 0.22x at the 200mm setting. It's not true macro but provides some scope for close-up photography, where the relatively small maximum aperture the lens supports demand effective stabilisation.
The VR II tag indicates a second-generation Vibration Reduction mechanism, which was a feature of the previous model. It employs two pairs of gyro sensors to detect pitch (vertical) and yaw (horizontal) movements.

The gyro sensors and electronics in the VR II stabilisation system. (Source: Nikon.)

This information is sent to two voice coil motors, which shift certain internal elements to counteract the detected motion. Nikon claims users can shoot with shutter speeds roughly four f-stops lower than they could with an unstabilised lens.

Two VR modes are provided: Normal and Active. The Normal mode is for shooting from a stationary base, while the Active mode is designed to provide compensation when shooting from a moving platform, such as a vehicle or ship. VR can also be switched off when the camera is tripod-mounted.

Handling
The review lens was an excellent match for the Nikon D300s body that was supplied for our review. It would be equally compatible with most other Nikon DX bodies, although perhaps a tad heavy for the D3000.

The zoom ring is located towards the front of the lens barrel. Roughly 20mm wide, it has approximately 18 mm of ridged rubber grip with a trailing edge that carries engraved settings for the 18mm, 24mm, 35mm 50mm, 70mm 135mm and 200mm focal lengths. The zoom ring moves through almost half a turn across its range. Maximum and minimum apertures change as shown in the table below.

Behind the zoom ring is a recessed distance scale with settings for 0.5, 1 and 3 metres plus infinity. The focusing ring lies behind this scale and has a 10 mm wide ridged rubber grip that rotates through roughly one third of a turn.

Three slider switches are located on the side of the lens barrel behind the focusing ring, covering the M/A and M focusing modes, VR on and off and Normal and Active VR settings. The zoom lock is positioned further forward between the zoom and focusing rings. It clicks into place at the 18mm focal length setting to prevent zoom creep when the lens is pointed downwards.

Performance
On test, this lens was well matched to the sensor in the D300s in terms of colour rendition and contrast. However, it was found to suffer from noticeable barrel distortion at the 18mm focal length setting. This was largely resolved by 24mm but changed to pincushion distortion, which was obvious from the 70mm focal length on. Rectilinear distortion is not uncommon in extended-range zoom lenses, although it is seldom quite so obvious over so much of the zoom range.

In our Imatest tests, resolution remained relatively high throughout the aperture and focal length range, although not quite up to the potential of the sensor in the D300s.  Best results were obtained from the shorter focal lengths and wider aperture settings. Edge softening was detected at all apertures and focal length settings, being slightly more pronounced at the widest apertures and less in the middle of the focal length range than at its extremes. The graph below shows the results of our tests.

Lateral chromatic aberration was generally well-controlled and remained within the ‘negligible' category at most aperture and focal length settings. No coloured fringing was detected in test shots.  The graph below shows the results of our Imatest tests.

Vignetting at wide apertures was barely visible with most focal length settings, although at 200mm, darkened corners could be seen in test shots. Two aberrations we seldom encounter were revealed in the course of our testing. Both are likely to be a consequence of the extended zoom design. Spherical aberration was evident in the degree of focus shifting required as apertures were stopped down. Curvature of field was also quite evident in the review lens.

Flare and ghosting were minimal unless the lens was pointed directly into the sun. Forced flaring resulted in starbursts, rainbow effects and circular patterns of various colours, as shown in the Sample Images section below. Contrast was not significantly reduced.

Out-of-focus blurring was mostly smooth, although some outlining could be seen around the brightest out-of-focus highlights at the widest lens apertures. The VR stabilisation system was a competent performer, enabling us to use shutter speeds as slow as 1/20 second with the 200mm focal length.

Buy this lens if:
- You want an all-in-one lens with good build quality.
- You'd like effective image stabilisation.
- You'd like a lens that requires no readjustment when you fit polarisers and graduated filters.

Don't buy this lens if:
- You want high resolution at all focal lengths, along with good edge-to-edge sharpness.
- You need true macro capabilities.

IMATEST GRAPHS
(based on JPEG files from the Nikon D300s)

SAMPLE IMAGES

Vignetting at 18mm f/3.5.


Vignetting at 200mm f/5.6.

18mm focal length; 1/100 second at f/10.


24mm focal length; 1/100 second at f/10.


35mm focal length; 1/125 second at f/10.


50mm focal length; 1/160 second at f/10.


70mm focal length; 1/200 second at f/10.


135mm focal length; 1/250 second at f/10.


200mm focal length; 1/320 second at f/10.


Extreme contre-jour lighting; 1/800 second at f/14.


Flare patterns; 1/80 second at f/11.

200mm focal length, 1/320 second at f/8.


200mm focal length, 1/320 second at f/9.


18mm focal length, 1/640 second at f/13.


200mm focal length, 1/400 second at f/10.


200mm focal length, 1/1000 second at f/5.6.


200mm focal length, 1/400 second at f/10.


200mm focal length, 1/640 second at f/13.


Close-up at 200mm; 1/20 second at f/5.6.


Bokeh at 200mm; 1/500 second at f/5.6.


Stabilisation test; 1/20 second at f/5.6.

Picture angle: 76 degrees to 8 degrees
Maximum aperture: f/3.5-5.6
Minimum aperture: f/22-36
Lens construction: 16 elements/12 groups (2 ED glass elements, 3 aspherical lens elements)
Lens mount: Nikon F bayonet
Diaphragm Blades: 7 (rounded)
Focus drive: Silent Wave Motor
Minimum focus: 50 cm
Maximum magnification: 0.22x
Filter size:  72mm
Dimensions (Diameter x L): Approx. 77 x 96.5 mm
Weight: Approx 565 grams
Supplied accessories: LC-72 front lens cap, LF-1 rear cap, HB-35 bayonet hood, CL-1018 soft pouch