The AF-S Nikkor 24-70mm f/2.8G, shown without its lens hood. (Source: Nikon.)
The AF-S Nikkor 24-70mm f/2.8G is a little lighter than its 14-24mm sibling and also slimmer and slightly longer, although still large and relatively heavy for a standard zoom. Constructed from 15 elements in 11 groups this lens has relatively complex optics, which goes part of the way to explaining its length and weight. Three ED (Extra-low dispersion) glass elements are included, along with three aspherical lenses. Nikon's new Nano Crystal Coat technology, which is designed to suppress internal reflections, has been applied to one element. The diagram below shows the position of the various elements.
Optical construction diagram for the AF-S Nikkor 24-70mm f/2.8G ED showing the location of the special elements. (Source: Nikon.)
As with the 14-24mm lens, the maximum aperture remains at f/2.8 for all focal length settings but, unlike the 14-24mm lens, this lens accepts screw-in filters via a 77mm thread in front of the front element. A 73mm long cylindrical lens hood (HB-40) attaches to the front of the lens via a bayonet mounting. It's quick and easy to fit - and equally quick to remove - and reverses over the lens barrel for carrying or storage.
Although designed for cameras with 36 x 24mm sensors, the new AF-S Nikkor 24-70mm can also be used on cameras with DX (23.7 x 15.7 mm) sensors, where it covers a focal length range equivalent to 36-105mm. However, its size, weight and price tag will probably ensure it is seldom partnered with Nikon's cheaper and lighter DSLRs, where it would be a poor match.
The closest focusing distance is 38 cm at focal length settings between 35mm and 50mm with both FX and DX bodies. Because the lens hood clips onto the outer barrel, the physical length with the hood attached remains constant at approximately 188 mm. Without the lens hood, the lens reduces to a minimum of 133 mm at the 50mm setting. Zooming out to 24mm extends the inner barrel approximately 20 mm, while zooming in to 70mm adds only 4 mm to the minimum length.
In line with other G-type lenses, this lens has no aperture ring. The focusing ring, which is approximately 20 mm wide, is located roughly 20 mm back from the lens hood. Behind it on the lens barrel is a distance scale in metres and feet, with distance settings for 0.38, 0.5, 0.7, 1 and 2 metres plus infinity. Left of this scale is a slider with M/A and M settings for swapping between manual (M) focusing and autofocus with manual over-ride (M/A).
The broad zoom ring is roughly 33 mm wide and carries engraved focal length settings for 24mm, 28mm, 35mm, 50mm and 70mm focal lengths on its trailing edge. Both focus and zoom rings have ridged rubber coatings, the ridges on the zoom ring being wider with three notches in each ridge for added grip security.
Silent Wave Motor (ultrasonic) focusing motors, which are found in all current Nikkor lenses, provide fast and near-silent autofocusing. A nine-bladed iris diaphragm closes to a rounded diaphragm opening that produces natural-looking out-of-focus elements. Internal focusing means the front element doesn't rotate and the barrel remains the same length, allowing use of angle-critical attachments (polarisers and graduates). In addition to the lens hood, this lens comes with a CL-M3 semi-soft case and end cap.
The CL-M3 semi-soft case supplied with the 24-70mm and 14-24mm lenses reviewed with the Nikon D3X camera body. (Source: Nikon.)
Handling
Thanks to its length and weight, the review lens felt nicely balanced on the Nikon D3X body we used for our tests. The zoom movement was positive and even throughout the focal length range. Shifting from the 24mm to the 70mm position requires roughly a quarter of a turn while, like the 14-24mm lens, the focus ring has 360 degree movement with the M setting but it takes only a quarter of a turn to go from close focus to infinity.
We found no tendency for the lens to extend when the camera was carried with the lens pointing downward and no unwanted changes in focal length as focus was adjusted. Despite lacking built-in image stabilisation, we were able to use shutter speeds as slow as 1/10 second in the course of our tests, thanks to the very solid platform provided by the D3X body.
Performance
Imatest testing showed the review lens capable of resolution that was only a little lower overall than the 14-24mm lens we reviewed at the same time. However, the 24-70mm lens had a significantly flatter field at wide lens apertures and greater consistency in resolution across the aperture and focal length range of the lens.
Edge softening due to curvature of field was detected at the widest apertures with the 24mm focal length setting. But differences between centre and edge resolution reduced significantly at smaller apertures. The graph below shows the result of our tests.
Lateral chromatic aberration was effectively negligible, as shown in the graph below. To reveal just low the CA results in our tests were, the red line on the graph marks the border between 'negligible' and 'low' CA. (Very few lenses record negligible CA throughout their aperture ranges.)
As expected for a professional lens, autofocusing was fast, almost silent and very accurate and we did not observe any hunting in the course of our tests, which covered a wide range of light levels. Distortion was also minimal for a zoom lens of this type. We observed a small amount of barrel distortion at the 24mm focal length, which shifted to very slight pincushioning at 70mm. Examples are shown below.
24mm setting at f/2.8.
70mm setting at f/2.8.
Vignetting was close to negligible and only observed at wide lens apertures. By f/4 it was effectively invisible. Examples are shown below.
24mm setting at f/2.8.
70mm setting at f/2.8.
Some veiling flare was seen in contre-jour shots but, overall, the test lens turned in a creditable performance with backlit subjects. Some examples are shown in the Sample Images section below.
Bokeh was significantly more attractive than the 14-24mm lens we have reviewed - and outstanding for a lens with aspherical elements. Unfortunately the close-focusing limit of 38cm prevents you from capitalising on this feature for close-up work. But when this lens is used for other types of subjects, it turns in the kind of performance you would expect for its very high price point and is a real pleasure to use.
Buy this lens if:
- You need a fast, standard range zoom lens and want the best of its class in build and excellent image quality.
- You require good performance with backlit subjects.
Don't buy this lens if:
- You want close-up versatility and performance.
- You need a compact, lightweight lens.
IMATEST GRAPHS
SAMPLE IMAGES
Veiling flare: 24mm focal length, 1/1000 second at f/2.8.
Veiling flare: 70mm focal length, 1/3000 second at f/2.8.
Backlighting: 24mm focal length, ISO 100, 1/2 second at f/16.
70mm focal length, 1/20 second at f/5.6.
70mm focal length, 1/250 second at f/8.
70mm focal length, 1/90 second at f/4.8.
Close-up: 24mm focal length, 1/125 second at f/2.8.
Close-up: 70mm focal length, 1/20 second at f/8.
Close-up: 70mm focal length, 1/180 second at f/2.8.
50mm focal length, ISO 400, 1/10 second at f/13.
(Additional sample images can be seen with the review of the Nikon D3X.)
Picture angle: 84-34 degrees 20 minutes (61-22 degrees 50 minutes with DX-format camera)
Maximum aperture: f/2.8
Minimum aperture: f/22
Lens construction: 15 elements in 11 groups (with 3 ED glass elements, 3 aspherical lenses and one Nano Crystal Coat)Lens mount: Nikon AF
Diaphragm Blades: 9 (rounded)
Focus drive: Silent Wave Motor (SWM)
Minimum focus: 38 cm
Filter size: 77 mm
Dimensions (Diameter x L): Approx. 83 x 133 mm
Weight: Approx. 900 grams