In addition to their optical qualities, 50mm lenses usually use a simple optical formula. They are thus small, light, fast, and usually affordable, although at least one sells for more than 1,000 USD.
Many qualities, yes, but many models, too, and choosing the right one isn’t always easy. That’s why we have produced this short analysis.
In the following pages we will mostly focus on two measures: the DxOMark Score and the resolution. We will also take into consideration other aspects such as distortion or chromatic aberrations, but they won’t appear listed in tables. You can, however, easily find them in the individual test report for each lens.
We decided to focus mostly on resolution and on the DxOMark score because they are a perfect match for everyday use. The DxOMark score is reflects the performance of a lens-body combination in a low-light environment (150 Lux with an exposure time of 1/60th second— similar to those in a normally lit living room, for example). The score measures the quantity and the quality of information received by the sensor at a certain aperture, and has a direct impact on the printing size you can expect. A score of 10 allows you to expect a perfect 20x30cm printing. If you double the print size, you must double the score as well.
We also focused on the pure resolution in order to indicate what aperture range is required for each lens in order to achieve the best definition under better lighting conditions.
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.
Canon EF 50mm f/1.4 USM
Let’s make it clear: this lens is the best 50mm choice among our 4 Canon-mount competitors, no matter the sensor size. It has the best definition of all the lenses displayed in these pages. Mounted on a 1Ds MkIII, it climbs to 63 lp/mm. No other lens-body couple listed here can outperform this. Moreover, this 50mm shows a very good MTF and has a very constant definition on the whole picture field. Vignetting is quite visible when fully opened, but almost disappears 2 stops later. Its only weakness, as with all the Canon lenses listed here, are that its chromatic aberrations are more noticeable than those for other brands.
The Canon EF 50 mm f/1.4 USM is the 50mm to have if you have a Canon body, no matter the sensor inside. It is a very sharp lens.
Canon EF 50mm f/1.2L USM
This is the most expensive 50mm among all our competitors. Unfortunately, however, it is not the most efficient as far as its metrics are concerned. Mounted on a 1Ds MkIII, this 50mm scores 10 lp/mm below the much cheaper 50mm f/1.4 USM. An analysis of the MTF chart also reveals another weakness of this lens, which does not manage to reach a balanced homogeneity on the whole field no matter how tight you close the lens. Moreover, the lens produces very dense chromatic aberrations.
Far from being the best on any Canon sensor, the Canon EF 50mm f1.2L USM 50mm is surpassed by most other lenses, and above all by the excellent 50mm f/1.4 USM.
Canon EF 50mm f/1.8II
As it was the case with the Nikon mount, Canon’s entry-level 50mm is also a tough competitor. If the others have a better pure resolution, this 50mm f1.8II proves very good in low-light conditions, reaching very good DxOMark scores at f/2.8 aperture. Mounted on a full-frame body, it has a slight tendency to produce too-soft edges. The problem is similar to that of the 50mm f1.2L USM, except for the price. And in fact, the 50mm f1/8II’s chromatic aberrations are well-contained. Mounted on an APS-C sensor, this 50mm shows the best definition, and its edges are much better. If they are too soft at f/2.8, closing 1 more stop produces a well-balanced image.
The Canon EF 50mm f/1.8 II is no match for the Cannon 50mm f/1.4 USM on a full-frame body, as the edges of the image may be too soft. On an APS-C sensor, however, it proves very good, especially at f/4.
Sigma 50mm f/1.4 EX DG HSM
Just like its Nikon-mount counterpart, this 50mm for Canon is a highly reliable lens, especially with respect to its central resolution. It reaches very good definition at f/2.8; moreover, it achieves its best DxOMark score fully opened. This is very good for a fast lens. But as it is the case with the Nikon mount, this 50mm shows some soft edges— softer than those for the Canon 50mm f/1.4 USM. Further, while the vignetting is well-contained, the chromatic aberrations are a bit strong.
An excellent performer on every Canon sensor, this Sigma is a perfect alternative if you want something other than the Canon EF 50mm f/1.4 USM.
Konica Minolta AF 50mm f/1.4
This lens behaves very well on a Sony full-frame sensor. The center resolution is very sharp and is easily found when stopping down to f/2.8. But you have to stop down to f/8 to find truly sharp edges. Vignetting is pronounced when fully opened, but almost vanishes at f/2.8, and completely disappears at f/5.6. Very good on a full-frame, this lens also provides very good definition on APS-C sensors.
The Konica Minolta AF 50 mm f/1.4 is good performer on any Sony sensor, suffering only from some soft edges at wide apertures.
Sony 50mm F/2.8 Macro
This Sony lens is one of the very few macro lenses listed here. In addition to its shorter focusing distance, its two main advantages are very good central resolution and almost no distortion. This is true for both APS-C and full-frame sensors. On a full-frame body, the center is very sharp even when wide open, but the edges are very soft. Stopping down to f/8 produces very good homogeneity. Slower than the Konica Minolta, this 50mm is also less sharp on an APS-C sensor.
The Sony 50mm f/2.8 Macro has perfect geometry and good definition on full-frame sensors, but is a bit soft on APS-C sensors.
Sony DT 50mm F1.8 SAM
Mounted on APS-C bodies, this 50mm proves very efficient, with a DxOMark score measured at 14 and reached at f/2.8. While similar in performance to the Konica Minolta lens listed above, this 50mm is even a bit sharper on an APS-C sensor. Moreover, it handles chromatic aberrations and distortion very well. The price-performance ratio is good. Sadly, however, you’ll have to choose a different lens if you use a full-frame body.
If you don’t intend to use a full-frame Sony body, the Sony DT 50mm F1.8 SAM 50mm is a good investment.
Pentax SMC D FA 50mm F/2.8 Macro
This Pentax macro lens is a solid competitor and behaves quite well on an APS-C sensor. It shows very good edges and a sharp center. But while the image field has good homogeneity whenfully opened, you have to stop down between f/5.6 and f/8 to reach the best resolution range. The remaining metrics are solid: no distortion, little vignetting, and very few chromatic aberrations contribute to a globally good lens.
The Pentax SMC D FA 50mm F3.8 Macro is a reliable lens, and is sharp when stopped down to f/5.6.
Designed for the future?
The various tests presented in this article show that globally, 50mm lenses are quality optics, and even if their optical formulas are not particularly new, they are good performers. While certain optics, notably zoom lenses, have some difficulties adapting to the latest sensor definitions, the 50mm lenses more successfully answer the challenge. And in fact, if you look at the results of the Canon 50 mm f/1,8 II on such camera bodies as the EOS 40D, 50D and 7D (which with their APS-C sensors at 10Mpx, 15Mpx, and 18Mpx, respectively, represent a significant evolution of definition), you will see that that its limiting resolution has similarly evolved. In terms of optical resolution, the 50mm lenses respond well to the APS-C sensors’ most stringent demands.