Nikkor AF 50mm f/1.8D
Small price, light weight… but this little 50mm is a very big surprise. This entry-level lens shows excellent performance—the best on a Nikon body among our four candidates. Not so bad for such an inexpensive lens! This is true for every full-frame sensor. But on an APS-C sensor, the Sigma 50mm F/1.4 EX DG HSM show higherresolution. Moreover, though the central resolution is good at f/2.8, closing to f/5.6 is necessary for better homogeneity. Otherwise the difference between the center and the edges will be noticeable. Distortion, vignetting, and chromatic aberrations are all handled very well.
The Nikkor AF 50mm f/1.8D is best choice on a full-frame body: cheap, sharp, and reliable. On an APS-C body, the Sigma 50mm F/1.4 DG EX HSM is a better choice.
Nikkor AF 50mm f/1.4D
With its wide-maximum aperture, this lens shows very good light transmission, allowing it to reach its best DxOMark scores fully opened on a full-frame sensor. But this lens has very few advantages over the others on a full-frame body. The others, including the Nikkor 50mm f/1.8D have a better resolution. Moreover, this 1.4D shows pronounced distortion, vignetting, and chromatic aberrations. Just as with the 1.8D, the 1.4D’s sharpest aperture range starts at f/2.8. But even stopped down to f/5.6, the 1.4D’s edges remain much softer than the center.
Although just average on a full-frame sensor, the 50mm f/1.4D performs much better on an APS-C body, reaching a very good DxOMark Score of 18 at f/2.8 and providing very good definition. However, the Sigma 50mm F1.G DG EX HSM is still sharper on this kind of sensor.
Average on full-frame, the Nikkor AF 50 mm f/1.4D performs much better on an APS-C body. But the Sigma remains better.
Nikkor 50mm f/1.4G
The newer 50mm in the Nikkor range achieves the best low-light mark among all the 50mm lenses listed here, with a very good DxOMark score of 28 reached on a Nikon D3s. The D3’s sensor helps a lot, certainly, but no other Nikon-mount lens does better. However, the 1.4G version keeps most of the 1.4D’s problems with vignetting. Though it has a very good central definition, this wide-aperture lens needs to be stopped down to f/5.6 to reach its best resolution—a bit sad for a 1.4 lens. Moreover, at f/5.6, the edges are still too soft. You have to close to f/8 to achieve the best homogeneity, which is fine when the light is good. Mounted on an APS-C sensor, this lens is fine, but others such as the Nikkor 50mm 1.4D or the Sigma 50mm f/1.4 DG EX HSM have a higher resolution.
The Nikkor 50mm f/1.4G is very good on a D3S in a low-light environment, and it is a good performer on any full-frame body.
Sigma 50mm f/1.4 EX DG HSM
This 50mm is an excellent performer, especially when mounted on an APS-C body, where it displays the highest resolution among our four Nikon-mountable lenses. On this size sensor, it handles vignetting and distortion well. Mounted on a full-frame body, it shows very good central resolution, but the rest of the field is a bit soft. Here again, it handles distortion and vignetting well, especially the vignetting, which almost disappears at f/2.8. The only small problem this Sigma lens shows is a noticeable amount of chromatic aberration—much higher than its Nikkor competitors.
The Sigma 50 mm f/1.4 EX DG HSM is is the best choice for an APS-C body, with a resolution much better than that of the others. On a full-frame, its homogeneity is a problem, as are the chromatic aberration it produces.