Nikkor AF 24-120mm f/3.5-5.6D IF - Review / Lab Test Report - Analysis
Lens Reviews - Nikon / Nikkor (APS-C)
Article Index
Introduction
Analysis

Distortion

The AF 24-120mm has a rather aggressive 5x zoom ratio so distortion is a little higher than average. Typical for such zooms there is some pronounced barrel distortion at 24mm (2.1%) changing to moderate pincushion distortion (0.8%) towards the long end of the zoom range. At 35mm the lens is free of distortion.

24mm:

35mm:

70mm:

120mm:

The chart above has a real-world size of about 120x80cm.

Vignetting

The AF 24-120mm VR is a full frame lens so on an APS-C DSLR it can take advantage of a sweet spot effect and generally the issue is quite well controlled. As to be expect the vignetting is most pronounced at 24mm @ f/3.5. At around 1EV vignetting may be visible at times here but the problem doesn't reach extreme degrees and if needed stopping down helps to reduce the issue significantly. At the other tested focal lengths the issue isn't really field relevant.

MTF (resolution)

In the MTF lab the lens was something of a mixed bag. The center resolution is very good regardless of the focal length and across the tested aperture range. At 24mm and 120mm the border resolution falls apart at wide-open aperture. However, stopping down to f/5.6 already results in a quite harmonious quality. At 35mm and 70mm the characteristic is less extreme. At wide-open aperture the contrast performance seems to suffer specifically at the long end of the zoom range.

The lens showed a focus shift when stopping down at the wide-end of the zoom range (residual spherical aberration). The tested sample may not have been the best representative of its species - there was a visible centering defect at 120mm.

Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations

Chromatic Aberrations (CAs)

Chromatic aberrations (color shadows at harsh contrast transitions) are very low between 24-70mm. CAs increase somewhat at 120mm with an average CA width beyond 1px at the image borders.

Verdict

The Nikkor AF 24-120mm f/3.5-5.6 D IF was an popular lens during the film era but on APS-C DSLRs the focal length range isn't all that attractive anymore. The performance of the lens is generally good with a high center resolution throughout the focal length range. Unfortunately the border quality is just so so at the extreme ends at large aperture settings. Apparently the contrast level is somewhat low at wide-open aperture so stopping down seems generally advisable. The distortion and vignetting characteristic is about average for a lens in this class. CAs are surprisingly low. Mechanically the lens feels generally fine but the rotating front element leaves something to be desired. The AF-S 24-120mm f/3.5-5.6G ED VR felt more convincing during the local tests.

Optical Quality:    
Mechanical Quality:
Price/Performance:discontinued
      
   What does this mean ?



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