Image quality
Image: At 24mm f/2.8 vignetting is quite severe, while barrel distortion (centre) and pincushioning (right) will also need correcting
Given its price, the Nikkor 24-85mm f/3.5-4.5G ED VR lens is very sharp. At the 24mm focal length, the lens is able to resolve to around 30 on our test chart when paired with the 24-million-pixel Nikon D3X. This is impressive, and when shooting at 24mm and f/8 it is almost a match for the more expensive Nikkor 24-70mm f/2.8 optic.
As expected, there is some drop off in sharpness when the lens is used with the aperture wide open, and also when apertures of f/16 or smaller are set. However, this gives a very wide range at which the lens is at its optimum, especially given its general-purpose nature. Set the focal length to 85mm and there is another drop in resolution, although our shots show that the lens is still capable of resolving up to around 28 on our chart, which is still very good.
The lens is not without its flaws, however. There is a slight fall-off in resolution towards the edges, although still with an acceptable amount of detail, particularly when you take into consideration the budget nature of the lens. Similarly, some green/magenta chromatic aberrations can be seen on high-contrast edges, although I found that the Nikon D3X corrected these automatically on all the JPEG images. Removing the colour fringing was simple enough in Adobe Camera Raw.
Of more concern is the barrel and pincushion distortion that are very noticeable and which could present a problem to anyone shooting in raw. If shooting architecture or seascapes, it will be beneficial to set up automated lens corrections in raw-conversion software to correct these distortions. For those photographers who use JPEG files, make sure that lens-distortion correction is switched on in-camera. This removes the vast majority of the distortion, althougha slight tweak may still be necessary in editing software for perfection.
Vignetting is also quite harsh when the lens is set to its 24mm wide end, even when the aperture is set to f/8. At other focal lengths vignetting is still noticeable, and it isn’t until 85mm at an aperture of f/8 that it is no longer visible, except on very close inspection. Again, most modern Nikon DSLRs should be able to correct for vignetting automatically. Raw-conversion software, such as DxO Optics Pro or Adobe Photoshop Lightroom, should also be able to automatically correct the vignette once the software has been updated to the latest version that will include data for this new Nikkor lens.
The images show a small section of our resolution chart. All the images in this test were taken with the AF-S Nikkor 24-85mm f/3.5-4.5G ED VR lens using a Nikon D3X, which has a full-frame 24.5-million-pixel sensor. The results are impressive, with the resolution only really decreasing at the 85mm focal length when the smallest aperture settings are used.
To view a large version of the resolution chart, click here
