Camera Accessories

Nikon's AF-S Nikkor 24-120mm f/3.5-5.6 G IF-ED lens covers a 5x zoom range and provides a suite of convenient focal length settings for owners of the company's D3 and D700 cameras but is also usable on DX models where the 1.5x crop factor gives it an equivalent focal length range of 36-180mm. Its affordable price tag makes it attractive to amateur photographers.

The first Nikon wide-angle zoom lens with Vibration Reduction (VR) technology, it claims to be able to support hand-held shooting at up to three f-stops slower at the 120mm focal length than you would otherwise obtain. The VR system relies on two gyro sensors to measure the speed and angle of camera movement. This information is used to compensate by shifting a group of lens elements.

Constructed from 15 elements arranged in 13 groups this lens includes two aspherical elements to reduce rectilinear distortion and two Extra-low Dispersion (ED) glass elements to counteract chromatic aberration. Internal Focus (IF) mechanisms provide smooth focusing and make it easy to use angle-critical filters, such as polarisers and graduates. The lens comes with an HB-25 lens hood. 

Focusing efficiency is also improved by Nikon's Silent Wave Motor (SWM) technology and the rounded iris diaphragm ensures out-of-focus elements in shots appear natural-looking and attractive. 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. The D-type design allows the lens to provide precise distance information for flash and ambient light exposure processes. 

Handling
Like most consumer-level lenses, the AF-S Nikkor 24-120mm f/3.5-5.6 G IF-ED is made mainly from polycarbonate, although it sports a stainless steel mounting plate, which sets it marginally above entry-level lenses. The filter ring, however, is plastic and accepts a 72mm filter. The review lens was a comfortable match for the D700 body we used for our tests and its build quality was similar to other Nikkor consumer lenses we've reviewed.

Both the zoom ring and the focusing ring have textured rubber coatings. The zoom ring is positioned towards the front and has wider ridging than the slightly narrower focusing ring. Moving from the 24mm to the 120mm position requires roughly a quarter of a turn. The aperture range changes with focal length, covering the following combinations:

The focusing ring appears to have unlimited 'play' but moves from the closest focus (0.5 metres) to infinity in roughly half a turn. The review lens had a slight roughness in the movement, which was disconcerting when the zoom mechanism was so smooth.  A distance window shows values in metres and feet.

Mounted on the side of the lens barrel are slider switches for engaging and disengaging VR stabilisation and autofocus. The manual/auto focus switch has two positions, M/A and M, indicating the focusing ring can be used with both auto and manual modes, regardless of the shooting mode selected. Only two positions are provided for the VR slider - on and off.

Performance
The best feature of the test lens's performance was its uniformity of exposures across both aperture and focal length ranges. We also found little evidence of edge or corner darkening.  Focusing was generally quiet, thanks to the Silent Wave Motor - but not blindingly fast and focus accuracy was uneven, particularly in low light levels and with moving subjects. 

The VR system delivered the claimed three-stop shooting advantage at most focal length settings (struggling a little at 120mm in lower light levels). We could take this out to four EV at the 24mm position.

Imatest showed the sample lens to be a patchy performer and revealed considerable edge softening at wide lens apertures. While the centre resolution was up to expectations at apertures between f/6.3 and f/13, it was comparatively low at the widest apertures and trailed off from f/14 to f/22. The graph below shows the results of our tests.

Lateral chromatic aberration was generally low, as shown in the graph below. Note: the red line marks the boundary between negligible and low CA values.

Barrel distortion was noticeable at the 24mm focal length. However, by 35mm images were distortion-free. We found slight pincushioning at the 50mm focal length, which continued to 120mm but was never enough to cause problems in normal use. Vignetting was negligible and only visible at the 24mm position when the lens aperture was wide open.

We captured a few discrete flare spots in some backlit shots but veiling and a loss of contrast was only evident when the sun was just outside the imaging field. Bokeh was nice - but not spectacularly attractive. Our best results were obtained at 120mm and, even then, light points weren't quite as soft as we'd like.

SAMPLE IMAGES

 
24mm focal length; 1/160 second at f/11; ISO 200.

 
120mm focal length; 1/250 second at f/11; ISO 200.

 
Autofocus error with moving subject. 1/640 second at f/5.6.

Backlighting. 120mm focal length; 1/30 second at f/20.

 
Lens flare spots. 24mm focal length; 1/400 second at f/10.

 
Shooting into the sun. 24mm focal length; 1/1000 second at f/8.

 
Bokeh: 120mm, 1/800 second at f/5.6; ISO 200.

 
120mm focal length; 1/200 second at f/7.1.

 
120mm focal length; 1/160 second at f/6.3.

 
120mm focal length; 1/50 second at f/11.

 
120mm focal length; 1/1000 second at f/5.6.

 
120mm focal length; 1/400 second at f/10.

 
120mm focal length; 1/320 second at f/8.

Picture angle: 20 degrees 30 minutes to 84 degrees
Maximum aperture: f/3.5
Minimum aperture: f/22
Lens construction: 15 elements in 13 groups with two ED glass elements
Lens mount: Nikon F-bayonet (compatible with FX, DX and 35mm film)
Maximum reproduction ratio: 1/4.8
Minimum focus: 0.5 metres
Optical stabilisation: Yes
Filter size:  72mm
Dimensions (Diameter x L): 77 x 94 mm
Weight: 575 grams