Camera Accessories

Designed for use with Nikon's DX-format cameras, the new AF-S DX Nikkor 18-105mm f/3.5-5.6G ED VR lens will be offered in some Nikon DSLR kits - including with the new D90, which was used for our tests.

Covering angles of view equivalent to 27mm to 157.5mm, it represents a good general-purpose lens for everyday photography and is priced accordingly. Nikon's internal focusing system enables the lens to be used with angle-critical filters, such as polarisers, while a Silent Wave Motor focus drive ensures autofocusing is fast and quiet.
Constructed in Nikon's Thailand factory, this lens consists of 15 elements in 11 groups, with one ED (Extra-low Dispersion) glass element plus an aspherical element to minimise the chance of various lens aberrations. Nikon's Super Integrated Coating (SIC) has been used to minimise internal reflections, thereby reducing the chance of flare and ghosting.

Built-in voice coil motors are used for lens-shift image stabilisation, which claims to offer approximately three f-stops of shutter speed advantage over a non-stabilised lens. Only one stabilisation mode is provided. The DX design indicates it is unsuitable for cameras with 'full frame' sensors - and also for film SLRs.

The G-type designation indicates this lens is designed for exclusive use with Nikon SLR models where the lens aperture is controlled from the camera body. It allows more accurate metering when used on the latest cameras with 3D colour matrix metering but won't support the auto aperture controls and wide-aperture metering on older cameras without the required electronic connections.

In line with its affordable price tag, most of this lens is made of  plastic, with the barrel textured to match the plastic bodies of the Nikon cameras it's designed for. High-quality industrial polycarbonate has been used for both barrel and mounting plate - and also the filter thread. Internal focusing ensures the front element retains a fixed orientation, regardless of the focal length setting. The zoom ring is positioned towards the front of the lens barrel and is approximately 45mm thick. Just under 30mm of this is a rubberised grip with ridges for comfort and security. Six focal length settings are engraved at the camera end of the focusing ring, covering 18, 24, 35, 50, 70 and 105mm settings.

Behind the zoom ring is a narrow (8mm wide) focusing ring, which also has a ridged rubber coating. No distance scale is provided; nor is there a depth-of-field scale of infrared focus index. On the side of the lens are two sliders, the top one switching between auto and manual focusing and the lower one turning the VR (vibration reduction) stabilisation on and off. The lens is supplied with a petal-shaped lens hood (HB-32), end caps and a soft carrying pouch (CL-1018).   

Handling
The review lens fitted easily - and snugly - onto the D90 body, where it was well balanced and a very natural fit with the camera. The Silent Wave Motor drive was fast and very quiet. A soft beep is audible when focus is achieved and the selected AF points are outlined in red with compatible cameras.

Both the zoom and focusing rings moved smoothly and positively and the lens showed no sign of extending when the camera was carried with the lens pointing downwards. (No zoom lock is provided.) Moving from the 18mm to the 105mm focal length requires a quarter of a turn and lengthens the lens barrel by 45mm. Setting intermediate focal lengths accurately was easy as the engraved marking on the lens barrel perfectly matched the focal length settings.

The focusing ring moves through 360 degrees when the slider is set to A and about a third of a turn with the M setting. It feels a little slacker than the zoom ring but the degree of focusing precision provided should be adequate for most users. 

Performance
Imatest showed the AF-S DX Nikkor 18-105mm f/3.5-5.6G ED VR lens to be a good partner for the D90 and a competent although not stellar - performer. Highest resolutions were recorded a couple of stops down from maximum aperture and resolution declined steeply from f/20 onwards. We suspect diffraction limitations were largely responsible for this loss of resolution and wonder why Nikon didn't limit the minimum aperture to f/22 for all focal length settings.

The highest resolution was recorded at the 50mm focal length, with the 35mm focal length close behind. The graph below shows the results of our Imatest tests at all lens aperture and focal length settings. (Test shots were taken at ISO 200.)

Lateral chromatic aberration remained in the 'insignificant' zone for all lens aperture/focal length combinations. The graph below shows the results of our Imatest tests, using figures for the edge of the frame (where C.A. is more likely to be visible). The red line at 0.04% delineates the border between the 'insignificant' and 'low' zones. We found no evidence of coloured fringing in test shots taken in contrasty conditions.

Slight corner vignetting (edge darkening) was found in test shots where subjects were photographed with white backgrounds. Barrel distortion was observed in test shots taken with the 18mm setting but it vanished by 25mm to be replaced by slight pincushioning at 105mm. At no time was either distortion severe enough to affect everyday photography.

Flare was only visible when the camera was pointed directly towards the sun and even then it was well controlled. Bokeh was soft and quite attractive. The image stabilisation system performed extremely well and we were able to use the camera hand-held at shutter speeds down to 1/8 second with the 50mm focal length and 1/13 second at 70mm.

SAMPLE IMAGES

 
18mm focal length setting.

105mm focal length setting from the same shootign position as the photograph above.

Corner vignetting at 70mm focal length, 1/80 second at f/5.3.

 
Tests of the VR stabilisation system:  50mm focal length, 1/8 second at f/5.

 
70mm focal length, 1/13 second at f/5.3.

 
Bokeh: 105mm focal length, 1/800 second at f/5.6.

 
Flare: 35mm focal length, 1/500 second at f/11.

66mm focal length, 1/200 second at f/9.

105mm focal length, 1/50 second at f/9.

 
105mm focal length, 1/50 second at f/6.3.

 
105mm focal length, 1/15 second at f/13.

Picture angle: 76 degrees to 15 degrees 20 minutes
Maximum aperture: f/3.5-5.6
Minimum aperture:
Lens construction: 15 elements in 11 groups
Lens mount: Nikon F-Bayonet
Diaphragm Blades:  7 (rounded)
Minimum focus: 0.45 metres at all focal lengths
Filter size:  67mm
Dimensions (Diameter x L): 76 x 89 mm
Weight: Approx. 420 grams