AF Nikkor 50mm f/1.4D lens review
Introduction This classic lens has seven elements in
six groups, focuses up to 45cm, is 64.5*42.5mm in dimensions, and
weighs only 230g. The maximum aperture of f/1.4 makes it indispensable
for low-light photography; another direct result is a very bright
view-finder when the lens is mounted on your camera. Though made
of plastic, it is reasonably well built. It handles very well and
balances perfectly on all Nikon bodies I have tried it on (F80,
F100, F6 and D70s). |
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Autofocus
One of the myths created by marketing people is that screw driven lenses are much slower to focus than the AF-S lenses. Contrary to this persuasive idea, my experience indicates that autofocus speed and accuracy mainly depend on the camera's autofocus module. When mounted on an F100, the lens focuses very fast yet with occasional hunting. On an F6 it autofocuses pretty much as fast as any AF-S lens with no hunting, albeit a bit more audibly.
Sharpness
At f/1.4 and f/2 the lens' performance is not outstanding as there is discernable softness across the whole image. The difference in sharpness between corners and the center is almost indistinguishable, though. From f/4 through f/11 the lens performs very well and the images it delivers are quite crisp corner to center. At f/2.8 and f/16 sharpness is a tiny bit worse than at its best, although one has to look really hard to see that difference - it took me a minute to see it with a 10X loupe.
If we turn away from the tests and to real-life experience, my overall impression from using the lens is that it is equally sharp from f/2.8 through f/16. Despite the fact that the lens was rated at 4.2 by Photodo.com I, however, have always had a persistent feeling that, generally, it is not as sharp as it should be considering its relatively simple design and a long history of design and production. This subjective evaluation perhaps can be explained by the fact that the lens exhibits very high weighted MTF numbers at both 10 and 20 lp/mm (contrast) yet its weighted MTF at 40 lp/mm (resolution) is significantly lower. Lens sample variation might be another plausible explanation.
Light fall-off
f/1.4 |
f/2 |
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f/2.8 |
f/4 |
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The lens shows visible light fall-off from f/1.4 through f/2.8. Its degree would be unacceptable to me at f/1.4; for some situations it might be tolerable at f/2. It is practically gone by f/2.8 - at this aperture the aberration is only slightly visible in the furthest corners and insignificant for real-life shooting. There is no light fall-off from f/4 on.
Distortion
Although some official Web sites claim that this lens is distortion-free (as here), I am afraid it is not - it in fact shows noticeable yet probably insignificant for most practical applications barrel distortion. My experience also shows that distortion is more pronounced at closer distances (closer than ten meters).
Flare and Ghosting
Once the standard of optical excellence, this lens has been being eclipsed by all the innovations that have been going into Nikon's top-end lenses. Even some of the top-end zoom lenses (e.g., AF-S Zoom-Nikkor 17-35mm f/2.8D IF-ED) seem to outperform the venerable prime lens in some areas, which includes flare control. While you will not see anything nasty when putting bright sources of light in the frame, you are likely to notice some flare and overall contrast deterioration. In other words, it is not bad but I have seen better performance.
Bokeh
I took pictures of the edge of a fountain with the city lights at infinity (in out-of-focus area) to check how out-of-focus areas would look.
f/1.4 |
f/1.4 (part of the image) |
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Bokeh is rather unsatisfactory at f/1.4 - the blur circles of distant lights are not evenly illuminated with their edges being well-defined and brighter than their center. In other images which I am not posting here out-of-focus areas did not look nice in the day-light either.
f/2.8 |
f/2.8 (part of the image) |
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Bokeh is neither good nor bad at f/2.8 - it is plain
neutral. The blur circles of light are evenly illuminated. Please note
that the circles are actually seven-sided heptagons, which is due to the
fact that the lens has seven diaphragm blades.
f/4 |
f/4 (part of the image) |
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Results at f/4 are quite similar to those at f/2.8, although out-of-focus lights seem somewhat softer.
f/5.6 |
f/5.6 (part of the image) |
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At f/5.6 bokeh is quite good - the circles are circles again, they are relatively evenly illuminated with edges being somewhat softer and not as bright. The only problem is that at this aperture the depth of field is quite deep and in real shooting conditions it might be a bit difficult to get background lights blurred.
Conclusions
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By and large, this is a good enough lens that deserves a place in every photographer's photo bag. I would give it four points out of five. It is fast, light and I love the shallow depth of field one can achieve with it without compromising quality of the image. From the standpoint of the aspects reviewed above, the lens does not perform that well at f/1.4 and I would avoid using it at this aperture unless I have no other choice; pretty much the same holds at f/2, although its performance does improve at this aperture. The lens is perfectly usable in the f/2.8 - f/16 range. When shooting conditions allow and I do not need the quite shallow depth of field that I love to use often, I stop it down to f/5.6 to achieve the best image quality. |
Update - the lens on a 6MP 1.5X crop factor DSLR
On a DSLR with a 1.5X crop factor the lens has an angle of view equivalent to that of a 75mm lens on a full-frame 35mm SLR camera. If you are the photographer who always dreamt about owning the AF Nikkor 80mm f/1.4D lens but could never afford one, buy the 50mm lens, mount it on your Nikon DSLR and your dream comes true at a much lower price!
It was quite interesting to see, though, how the lens would behave on a digital camera of a relatively low resolution. Generally, my findings have been consistent with the results of the previous tests with film. Furthermore, digital capture - even at 6MP - appears a far more merciless lens tester. The D70s used in the tests accentuated all the shortcomings of the lens that I analyzed above.
First of all, let's have a look at how the lens fared in the department of sharpness.
f/1.4 |
f/2 |
f/2.8 |
f/5.6 |
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The images above are crops of the furthest corner of a picture that was taken at different apertures and the resolution of 6MP (3008X2000 pixels) and recorded in JPG Fine format with no sharpening applied; the lens was focused on infinity. As you can see, it performs quite poorly between f/1.4 and f/2.8 and shows significant loss of resolution and contrast.
As far as light fall-off is concerned, it is still quite pronounced at f/1.4 and, if you insist on being neurotic, visible at f/1.8 - despite the 1.5X crop factor. At f/1.4 it actually has a very interesting pattern - it is not that just the corners are a bit dark; it is that the whole frame is unevenly lit. This, of course, once again underlines the fact that if the lens is mounted on a full-frame 35mm SLR light fall-off is really bad at this aperture.
Distortion is less pronounced than on a full-frame 35mm film camera yet still noticeable, which once again confirms that the lens is not distortion free.
All of the above once again confirms that the lens is not a great performer in the f/1.4 - f/2.8 range. While light fall-off and distortion become less of an issue on a digital camera with a 1.5X crop factor (these aberrations can also be dealt with during digital post-processing), problems with sharpness become more pressing even on a 6MP DSLR. In the final analysis I personally decided that there is no point in having a very fast lens that does not perform well wide-open. Time for a major update, Nikon!