Nikkor AF 24mm f/2.8 D (FX) - Review / Test Report - Analysis
Lens Reviews - Nikon / Nikkor (full format)

Distortion

The lens shows moderate barrel distortion at around 1.8% with a little mustache sub-style.

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

Vignetting

The Nikkor shows very pronounced light falloff towards the image corners wide open and also at f/4. Stopped down to f/5.6 and beyond vignetting is reduced to a level that is no longer an issue for most subjects.

We're performing our vignetting analysis based on (uncorrected) JPEGs straight from the camera. The JPG engine of the Nikon D3x features a rather flat gradation curve, thus has a moderate contrast characteristic, resulting in comparatively low vignetting figures - the corresponding Canon figures are roughly 40% higher due to the more aggressive default contrast setting.

MTF (resolution)

In the image center the lens shows very good resolution wide open and at f/4, reaching excellent sharpness from f/5.6 onwards (until diffraction limits the maximum achievable resolution at f/11 and beyond).

The image borders and corners are rather soft wide open, but stopping help to raise the sharpness to good values at f/4 and very good resolution at f/5.6 and beyond. The performance peak of the lens is reached at f/8.

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 moderate at large apertures, but increase considerably by stopping down. However, CAs can easily be corrected in software or by the camera itself (if you shoot JPEGs and own a current Nikon DSLR).

Bokeh

A 24mm prime is certainly not primarily designed to throw the background out of focus (to the contrary, actually). However, with its ability to focus rather close combined with the large aperture the lens is able to separate the main subject from the background (at least for larger subject-to-background distances). So, let's have a quick look at the bokeh quality.

Out of focus areas show some nervousness and doubled contures. Background highlights are quite distorted towards the image borders at f/2.8 and f/4, but circular at f/5.6. Quite strong outlining increases the overall unpleasant character of the lens' bokeh.




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