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AF-S DX 18-70mm f/3.5-4.5G IF-ED
Text and pictures by Simon Stafford.
The DX 18-70mm has a new bayonet hood, the HB-32
The lens reaches its maximum extension at the 70mm setting
The AF-S DX 18-70mm f/3.5-4.5G IF-ED mounted on the new D70. The two will be available as a kit
A G-type lens it has no conventional aperture ring
The small, compact size of the DX 18-70mm compliments the dimensions of the D70
The fourth DX-format Nikkor lens to be introduced the AF-S DX 18-70mm f/3.5-4.5G IF-ED was announced at the same time as the D70 SLR camera, with which it will be offered as a kit. The press release from Nikon suggests, “It effectively upgrades two existing AF Nikkors – it is smaller lighter and more versatile than the existing AF 28-105mm while offering greater zoom range than the similarly sized AF 18-35mm”, since it has an effective angle of view equivalent to 27-105mm on the 135 film format. As a DX Nikkor this lens has an optical geometry that is optimised for the DX format sensor used in Nikon digital SLR cameras.
A sophisticated lens using 15 elements arranged in 13 groups, of which three are made of ED glass and one is aspherical. It is a compact, light lens weighing just 390g that accepts 67mm thread filters, and has a bayonet lens hood the HB-32. As a G-type design it has no conventional aperture ring but offers a range of variable maximum apertures from f/3.5 at 18mm, f/3.8 at 24mm, f/4.2 at 35mm, and f/4.5 from 50mm onwards, with a minimum aperture of f/22.
The DX 18-70 seen from above a D70
The layout of the two-ring design is similar to other recently released Zoom-Nikkor lenses where the focusing ring is closest to the camera body. The small physical size of the lens means that the focus ring is not very wide and like the DX 12-24mm f/4 it has a low profile that makes handling a little awkward, although like the broader zoom ring it has a well balanced feel. The front filter ring does not rotate with the zoom or focus action to facilitate the use of filters. It lacks an IR focusing index mark and any depth-of-field scale. On the side of the lens barrel is a sliding switch to select either the manual or A/M (AF with manual over-ride) focus mode.
Results from an initial test confirmed that the use of a silent wave motor ensures a quick and positive AF response, even with the modest CAM900 AF module of the D70. At this very early stage I need to conduct more tests before I draw any conclusions about optical performance.
Update: 10th August 2004
As described above this lens was introduced to accompany the D70 and forms a "starter kit" with a price point aimed squarely at the dedicated enthusiast photographer market. I have spent the past few months shooting many hundreds of pictures with this compact and lightweight lens, and now feel qualified to report my findings. The first of which is do not be fooled by its cost! I agree that it may not have the armoured robust build quality of "professional" specification Nikkor lenses but before you dismiss it on these grounds ask yourself how much abuse are you going to subject your equipment to?
It is not as though Nikon have cut corners as the lens even includes a rubber gasket to seal the lens mount flange against ingress of moisture and dust, which is something my AF-S 17-35mm f/2.8 and AF-S 28-70mm f/2.8 lenses lack.
The inclusion of Extra-low Dispersion (ED) glass and aspherical elements means the lens produces images with a high level of contrast, vivid, saturated colour, and a high level of sharpness. Between 18 and 24mm there is a hint of softness in the extreme corners at the widest apertures but stopped down to f/5.6 - f/11 this trait is gone. Likewise there is a perceptible but by no means intrusive fall off of illumination at the edges of the frame within the same focal length range at maximum aperture, which is also gone once stopped down to f/5.6 or less.
The most obvious aberration is the level of barrel distortion at the wide end that shifts through a neutral zone between 24 to 50mm, and on to very mild pincushion distortion at 70mm. So the lens is not suitable for critical applications when shooting certain subjects such as architecture. To be hyper critical there have been occasions when a mere trace of chromatic aberration has crept into images that contain areas of fine detail with high contrast but for all practical purposes this can be ignored.
Despite its price tag Nikon do not appear to have skimped on lens coating applications so when I have turned this lens to shoot toward a light source I have found that it is remarkably resistant to flare and ghosting. The HB-32 hood is also practicably deep, which helps matters in this respect as well.
Finally, to reiterate the point this is a DX-type lens and as such the image circle it projects is considerably smaller than that of a lens designed for the 135-film format. So before I get a deluge of e-mails - no it will not work on any Nikon 35mm film camera, because the image will suffer from severe vignetting.
Nikon should be rightly proud of the D70 and in the AF-S DX 18-70mm f/3.5-4.5G IF-ED they have a lens that does full justice to the camera; the pair make a winning combination!
Focal length: 18-70mm
Maximum aperture: f/3.5-4.5
Aperture range: f/3.5-4.5 to f/22-29
Lens construction: 15 elements / 13 groups (3x ED glass, 1x aspherical)
Picture angle: 76°-22°50’ (with D1/D2-series /D100/D70)
Focus distance: 0.38m (at all focal length settings)
Attachment size: 67mm
Hood: HB-32 (bayonet fit)
Dimensions (D/L): 73mm x 75.5mm
Note: A G-type Nikkor series lens does not have an aperture ring; therefore, it is compatible with all exposure modes of the Nikon F5, F100, F80, F65, F60, F55, F50, F-401 series, PRONEA 600i, PRONEA S, D1& 2 series, D100, and D70 but only the P and S modes of the F4, F90-series, F70, F-801 series and F-601M. Other cameras are not compatible.
© Simon Stafford