Camera Accessories

Designed for both 'full frame' FX  and 'APS-C' DX cameras, the new AF-S Nikkor 24-70mm 1:2.8G ED lens is designed to partner the AF-S Nikkor 14-24mm 1:2.8G ED lens we reviewed recently. Capable of covering subjects as diverse as tight portraits and expansive scenes, this lens maintains an f/2.8 aperture throughout the focal length range. Like the 14-24mm lens, it is built to Nikon's professional DSLR standards with high-quality dust and moisture sealing.

Magnesium die-cast casings have been used to reduce the weight of these new lenses. Rubberised focusing and zoom rings are provided for quick and easy operation. The focusing ring is towards the front, while the broader zoom ring is closer to the camera body. Between them is a distance scale with feet and meter markings for focusing but no depth of field or infrared indicators. Six markings are provided on the meter scale: 0.38, 0.5, 0.7, 1, 2 and infinity. The rear edge of the zoom ring carries an engraved focal length scale covering 24, 28, 35, 50 and 70mm settings.

The optical construction of this lens is similar to the 14-24mm lens. Consisting of 15 elements in 11 groups, it includes three ED glass elements, three aspherical lenses and one Nano Crystal Coated lens element. A large-diameter PGM (Precision Glass Moulding) element helps to eliminate coma and other types of aberration even at the widest aperture.

Two different types of coating are used to reduce internal reflections and ensure optimal colour reproduction. Nikon's Nano Crystal Coat is extra-low refractive index coating that minimises internal lens element reflections across a wide range of wavelengths and is particularly effective in reducing ghosting and flare. Nikon's Super Integrated Coating reduces reflections in the wider wavelength range to ensure superior colour reproduction.

The 24-70mm is also equipped with Nikon's SWM (Silent Wave Motor) technology to ensure fast and quiet autofocus operation. A slider on the side of the lens barrel has settings for M and M/A modes, the latter allowing users to switch quickly from automatic to manual focusing, even during AF servo operation.

Unlike the 14-24mm lens, the petal-shaped lens hood on the 24-70mm lens is detachable and fits onto the front of the lens with a bayonet mount. A click-in lock holds it in place. The lens is supplied with an elegant semi-rigid carry pouch with a double-zipper and Velcro closing. 

Handling
Despite its relative bulk and size, the review lens was a delight to use on the Nikon D3 body we used for this assessment. It was a comfortable, well-balanced match for the D3's body and the high speed and quietness of the SWM focusing drive were very impressive. Focusing was very fast and accurate and we found no instances of hunting in low-light conditions.

This lens would be equally suited to the D300 or D200 models but may be over-large (and over-costly) for users of the D40 or D40X. Both the focusing and zoom rings moved smoothly and positively and showed no tendency to 'creep' when the camera is held facing downwards.

Moving from the 24mm to the 70mm focal length requires just over a quarter of a turn, which is comfortable and easily handled. Setting intermediate focal lengths precisely was relatively easy as the lens settings matched the engraved focal lengths extremely well.


Taken at 24mm.


Taken at 70mm.

The focusing ring has a slightly shorter 'throw' than the zoom ring and provides a high degree of precision. There is no need for a manual/auto focus switch on the lens as the focusing ring can be used with all settings, regardless of the shooting mode selected. Manual focusing in live view mode is fully supported.


Depth of field example: 70mm at f/2.8.

Depth of field example: 70mm at f/22.

Performance
Imatest testing showed the supplied lens to be an outstanding performer at apertures between f/3.2 and f/8.0, particularly in the centre of the imaging field. Edge quality was also very good between f/4.0 and f/9.0, although the curved field at 24mm produced some corner softening at wide apertures. At smaller apertures, performance tailed off gradually but remained well above average. The graph below plots the centre resolution from our Imatest tests against lens aperture and focal length.



Lateral chromatic aberration was also very low and never ventured above the 'insignificant' level at any focal length setting. (For reference, the borderline between 'insignificant' and 'low' is 0.004% of distance to corner.) A graph plotting the CA values against the focal length setting is provided below.



Vignetting (edge darkening) was negligible at all apertures and focal length settings and corner softening was only apparent at the 24mm setting. Rectilinear distortion was barely detectable. Thanks to the large image sensor on the D3, it was possible to obtain true out-of-focus backgrounds at f/2.8 with all focal length settings. The resulting bokeh (out-of-focus blur) was very smooth and attractive, as shown in the photograph below.

We found little evidence of flare in shots taken with the lens pointing towards the sun - as long as direct light from the solar disk was prevented from entering the lens.


Backlighting.


No coloured fringing was observed in test shots.

Focal length range: 24-70mm
Picture angle: 61^o to 22^o50' with FX format cameras; 71^o to 27^o40' with DX format cameras
Maximum aperture: f/2.8
Minimum aperture: f/22
Lens construction: 15 elements in 11 groups (3 ED glass elements, 3 aspherical lenses and 1 Nano Crystal Coated lens element)
Lens mount: Nikon F
Diaphragm Blades: 9
Minimum focus: 41 cm at 24mm, 39 cm at 28mm to 50mm, 40 cm at 70mm
Filter size: 77mm
Dimensions (Diameter x L): 83 x 133mm
Weight: Approx. 900 grams