Sigma 50mm f1.4 Art review - Quality
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Quality

We’re so excited about the Sigma 50mm f1.4 ART that we’ve produced five pages of results for you, comparing it against a variety of cheaper and more expensive lenses for both Canon and Nikon bodies. We’ll start with a page of general results from Thomas, which includes numerous comparisons against the more affordable Nikkor 50mm f1.4G and the King of the standard lenses, the Zeiss Otus 55mm f1.4; Thomas tested the Nikon version on his D800, but the results and comparisons are equally applicable to those who intend to use either lens on a Canon body.

On the second page Thomas turns to his charts for an in-depth comparison against two more affordable models: the Nikkor 50mm f1.4G and Sigma’s non-ART 50mm f1.4, allowing you to see if it’s worth spending the extra on the ART lens. On the third page Thomas looks to the higher-end, comparing the Sigma 50mm f1.4 ART against the Nikkor 58mm f1.4G and the Zeiss Otus 55mm f1.4, both of which are more expensive, especially the Otus.

Then on page four of our results, Gordon compares the sharpness of the Sigma 50mm f1.4 ART against the Canon EF 50mm f1.4 USM and Canon EF 50mm f1.2L USM. One’s cheaper and one’s more expensive, but which one will perform the best? And finally Gordon concludes our in-depth test by comparing the out-of-focus bokeh effects between the Sigma 50mm f1.4 ART and the Canon EF 50mm f1.4 USM and EF 50mm f1.2L USM. No stone has been left unturned, so without further ado, here are the results! You can navigate between the results and gallery pages using the index above.

Performance at large distances

Technical charts provide useful results when testing lenses, but only tell one side of the story at a relatively close distance of 40x focal length (i.e. at 2.0m). The other side is how well they perform when focused on distant subjects, effectively at infinity. Therefore I do a series of test-shots of a landscape dubbed the “Unremarkables” where you can measure distances in km, not meter. I use this scene to show you how the lenses perform when almost everything is at infinity. I set White Balance to a standard daylight value to make them comparable across lenses shot at the same day and also try to make exposure comparable. There’s no tinkering with vignette-control so you see it here as it is produced by the lens. Focus was manually acquired at the largest aperture in live-view and not changed for other apertures.

You can click on the image to access the large original. Please respect our copyright and only use those images for personal use.

The main image shows the complete scene at maximum aperture to give you an impression of the angle of view and to judge vignetting. This is followed by one row of 100% crops from the center for each aperture from f1.4 to f11:

 

Unremarkables: Infinity shots with Sigma 50mm f/1.4 ART on a D800
50mm, f1.4, 100 ISO; Below: 100% crops from the main image at different apertures
Nikkor 50mm f/1.4G
with Nikon D800
100% crop from center
Sigma 50mm f/1.4 ART
with Nikon D800
100% crop from center
Zeiss 55mm f/1.4 Otus
with Nikon D800
100% crop from center
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
55mm, f2.0, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
55mm, f2.8, 100 ISO
50mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
55mm, f4.0, 100 ISO
50mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
55mm, f5.6, 100 ISO
50mm, f8.0, 100 ISO
50mm, f8.0, 100 ISO
55mm, f8.0, 100 ISO
50mm, f11, 100 ISO
50mm, f11, 100 ISO
55mm, f11, 100 ISO

 

Best performance in the center comes from the new Sigma ART. The Zeiss Otus is less bitingly sharp and the Nikon brings up the rear in this comparison. By f5.6 all three lenses look almost the same.

The following table shows 100% crops from the APS-C corner:

 

Nikkor 50mm f/1.4G
with Nikon D800
crop from APS-C corner
Sigma 50mm f/1.4 ART
with Nikon D800
crop from APS-C corner
Zeiss 55mm f/1.4 Otus
with Nikon D800
crop from APS-C corner
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
55mm, f2.0, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
55mm, f2.8, 100 ISO
50mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
55mm, f4.0, 100 ISO
50mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
55mm, f5.6, 100 ISO
50mm, f8.0, 100 ISO
50mm, f8.0, 100 ISO
55mm, f8.0, 100 ISO
50mm, f11, 100 ISO
50mm, f11, 100 ISO
55mm, f11, 100 ISO

 

In the APS-C corner tables are turned: The Zeiss Otus pulls clearly ahead and both the Nikon 50/1.4G and the new Sigma ART look almost the same with a slight lead for the Sigma.

And finally there are the 100% crops from the corner of a 36MP full-frame 24 x 36 mm sensor:

 

Nikkor 50mm f/1.4G
with Nikon D800
100% crop from FF corner
Sigma 50mm f/1.4 ART
with Nikon D800
100% crop from FF corner
Zeiss 55mm f/1.4 Otus
with Nikon D800
100% crop from FF corner
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
55mm, f2.0, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
55mm, f2.8, 100 ISO
50mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
55mm, f4.0, 100 ISO
50mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
55mm, f5.6, 100 ISO
50mm, f8.0, 100 ISO
50mm, f8.0, 100 ISO
55mm, f8.0, 100 ISO
50mm, f11, 100 ISO
50mm, f11, 100 ISO
55mm, f11, 100 ISO

 

It is quite impressive how the Otus keeps its performance right up into the corners of the full-frame sensor, albeit with the highest vignetting of the three lenses. The new Sigma ART comes second place in sharpness probably held back by field-curvature that already showed at 2m shooting distance. And the Nikon is the worst wide open suffering from strong coma that shows in the light-streaking around bright areas. Stop down to f5.6 and most differences are gone with the Nikon surprisingly inching slightly ahead of the Sigma. The Sigma clearly shows the least vignetting of the three lenses.

When day turns into night the same scene proves to be a good test for coma. The 100% crops show the effect from the right corner at f1.4. Coma is much smaller than with the Nikon 50/1.4G where the lights are transformed into bird-like shapes. But the Otus reproduces the point-light sources best. Stepping down to f2.8 eliminates coma of the Sigma almost completely.

 

Unremarkables at night: Coma shots with Sigma 50mm f/1.4 ART on a D800
50mm, f1.4, 100 ISO; Below: 100% crops from the main image for different lenses
Nikkor 50mm f/1.4G
with Nikon D800
100% crop from FF-corner
Sigma 50mm f/1.4 ART
with Nikon D800
100% crop from FF-corner
Zeiss 55mm f/1.4 Otus
with Nikon D800
100% crop from FF-corner
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO

Rendering of out-of-focus subjects

This test is for the rendering of out-of-focus point-light sources in the background. The circle of confusion that is produced by this test is pretty indicative of Bokeh performance (in the background) and light fall-off. Ideally the out-of-focus image of the point-light is evenly lit and perfectly circular, with no “onion-rings”, and without green outlining (the sign of longitudinal CA). Large aperture lenses normally produce a squashed oval effect known as “cat’s eye” the further away from the optical axis the point-light is projected. This is due to optical vignetting in the lens barrel when light enters the lens from an angle. For an explanation of this effect have a look over at toothwalker.org.

 

Unremarkables at night: Out-of-focus shots with Sigma 50mm f/1.4 ART on a D800
50mm, f1.4, 100 ISO; Below: 50% crops from the main image for different lenses and apertures
Nikkor 50mm f/1.4G
with Nikon D800
50% crop from center
Sigma 50mm f/1.4 ART
with Nikon D800
50% crop from center
Zeiss 55mm f/1.4 Otus
with Nikon D800
50% crop from center
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
55mm, f2.0, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
55mm, f2.8, 100 ISO
50mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
55mm, f4.0, 100 ISO
50mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
55mm, f5.6, 100 ISO

A lot of observations can be made here. I’ll start with the green outlining (best seen around white blobs): this is worst with the Nikon 50mm f1.4G, best with the Otus. The new Sigma has some but not too distracting.

In terms of onion rings, the Nikon shows none (it has no aspherical element), while both the Sigma and the Otus show them to varying degrees: at f1.4 the rings are more pronounced with the Sigma, at f2.0 the Otus shows a bit more.

Now for roundness: when stopping down, all three lenses show signs of their nine aperture blades not forming a perfect circle. The Nikon deviates furthest from perfect roundedness at f2.0 but is ahead from f2.8 onwards. The Otus shows the nine-corners more clearly than the others.

Blob-size: all three lenses were focused in a way that would reproduce a subject in the focal plane at the exact same magnification of 1:30. That means focus was around 1.5m for the Nikon and the Sigma but around 1.65m for the Otus as it has a 10% longer focal length. At f1.4 both the Nikon and the new Sigma produce blobs of the same size, while the Otus has a 10% larger blob. When the lenses are stopped down to f2.0 the blob of the Sigma shrinks fastest: Its blob is now around 15% smaller than from the Nikon while the Otus’s blob is about 30% larger than Sigma’s. Stopping further down reduces the differences a bit.

The following table shows 50% crops from the APS-C corner:

 

Nikkor 50mm f/1.4G
with Nikon D800
50% crop from APS-C corner
Sigma 50mm f/1.4 ART
with Nikon D800
50% crop from APS-C corner
Zeiss 55mm f/1.4 Otus
with Nikon D800
50% crop from APS-C corner
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
55mm, f2.0, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
55mm, f2.8, 100 ISO
50mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
55mm, f4.0, 100 ISO
50mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
55mm, f5.6, 100 ISO

 

Towards the corners of a DX sensor some other irregularities show up, like the cat’s-eye effect: and a slight clipping from the mirror-box of the D800. The new Sigma behaves best in this case while the Otus shows the most prominent cat’s-eye effect. Stopping down to f2.8 eliminates the optical vignetting of all three lenses.

You can also observe some irregular light-distribution now: The Nikon is developing two bright spots in the corners of the cat’s eye which will make Bokeh more nervous in the corners of an image compared to the center. The new Sigma shows a little darkness creeping in on one side of the blob at f1.4 and f2. The Otus has the most even distribution of light in its blobs.

And finally there are the 50% crops from the corner of a full-frame 24 x 36 mm sensor:

 

Nikkor 50mm f/1.4G
with Nikon D800
50% crop from FF corner
Sigma 50mm f/1.4 ART
with Nikon D800
50% crop from FF corner
Zeiss 55mm f/1.4 Otus
with Nikon D800
50% crop from FF corner
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
55mm, f2.0, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
55mm, f2.8, 100 ISO
50mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
55mm, f4.0, 100 ISO
50mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
55mm, f5.6, 100 ISO

 

In the corner of a full-frame 24 x 36 mm sensor the new Sigma takes a clear lead: it produces the most well-rounded and largest blob at f1.4 and f2.0. Only a little green outlining can be seen. The Nikon’s blobs are 25% smaller in diameter at f1.4 and the Otus suffers from a pronounced cat’s-eye effect although the largest diameter of its blob is equal to that of the Sigma at f1.4. By the way, the Nikon lens shows that the mirror-box of the camera need not show up prominently at f1.4.
Stopping down leads to mostly well-rounded blobs for all lenses from f4.0 on.

Now let’s see how this analysis of out-of-focus point-light sources translates into Bokeh-performance shooting a book-shelf.

 

Books: Bokeh shots with Sigma 50mm f/1.4 ART on a D800
50mm, f1.4, 100 ISO; Below: 50% crops from the main image at f1.4 and f2.8
Nikkor 50mm f/1.4G
with Nikon D800
50% crop from foreground
Sigma 50mm f/1.4 ART
with Nikon D800
50% crop from foreground
Zeiss 55mm f/1.4 Otus
with Nikon D800
50% crop from foreground
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
55mm, f2.8, 100 ISO

 

In the foreground on the left border the Sigma has the “fattest” Bokeh at f1.4, at f2.8 the Otus has a slight lead. The Nikon is the least creamy of all.

 

Nikkor 50mm f/1.4G
with Nikon D800
50% crop from middle-ground
Sigma 50mm f/1.4 ART
with Nikon D800
50% crop from middle-ground
Zeiss 55mm f/1.4 Otus
with Nikon D800
50% crop from middle-ground
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
55mm, f2.8, 100 ISO

 

Looking at the middle-ground just behind the focus-plane the Otus shows the least coloration (loCA), the Sigma is second best, and the Nikon even introduces some magenta colors inside “e”s and “a”s.

 

Nikkor 50mm f/1.4G
with Nikon D800
50% crop from background
Sigma 50mm f/1.4 ART
with Nikon D800
50% crop from background
Zeiss 55mm f/1.4 Otus
with Nikon D800
50% crop from background
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
55mm, f2.8, 100 ISO

 

The background reveals an interesting effect: Stopping down can increase the quality of Bokeh. This has to do with the better circularity of the blobs that are at the periphery of an image. At f1.4 Nikon looks the most nervous while the new Sigma and the Otus look very close, perhaps with a slight edge for the Otus. At f2.8 the Sigma clearly renders the smaller circles of confusion compared to the Otus, so its Bokeh looks a bit less creamy.

Light fall-off

You might not bother too much about light fall-off as today’s cameras and post-processing software can compensate for this effect. But if the lens produces corners that are 2 EV below the center exposure you have to pull them up two stops for even lighting. This in turn might well expose noise in less than well-lit corners that you didn’t notice before. So the more even the light-distribution of a lens is across a sensor the better.

The following image shows full frames of an evenly lit subject captured with the new Sigma (1st row), Nikon 50/1.4G (2nd row), and the Zeiss Otus (3rd row) at f1.4 (left column), f2.0 (middle column), and f2.8 (right column). Processing was set to camera standard.

 

Vignetting on a D800
From top to bottom: Sigma 50mm f1.4 ART, Nikkor 50mm f1.4G and Zeiss Otus 55mm f1.4

 

As you can see the new Sigma shows much less light fall-off than the other two lenses, the worst at f1.4 being the Nikon 50/1.4G. For those interested: these results ties in with the observations on the diameter and area of out-of-focus blobs in the full-frame corner in the night-shots above. The larger the area of the blob in the corner the more light gets through to the sensor in these corners.

Flare/ghosting

Shooting normal or wide-angle lenses always runs the risk of catching a strong light-source like the sun shining directly into the lens. This could produce strange colorful ghosts-images or reduce contrast considerably through flare and glare.

The appearance of flare and ghosting depends on factors like the aperture and the angle of the light hitting the lens. So to judge the proclivity of a lens for these artifacts I went through a series of well calculated shots against a strong light source to provoke flare, glare, and ghosting at f1.4 and f8. The following image shows one of the worst flares that I could produce with this lens.

 

Flare/Glare: shot with Sigma 50mm f/1.4 ART at f8 on a D800
50mm, f8, 100 ISO

 

The flares are not very bright here but they reach across the frame. With the light even closer to the center of the image the flare becomes smaller but brighter. With the light outside the frame the lens behaves very well (with lens-hood attached) with only very faint ghosts. Of 23 shots in this test one other showed similar flare and 6 other shots produced weaker ones. There’s little veiling glare in these images and the blacks are really black.

Compared to the Nikon 50/1.4G the new Sigma behaves similarly, with the Sigma producing longer light-streaks radiating from the light-source. This may or may not be a welcome effect. There is also some dark magenta halo around the light-source as you can see in the image above which shows up regardless of aperture but can only be seen if the background is dark enough. The Otus is clearly more flare-resistant.

Sigma 50mm f1.4 ART vs Nikon 50mm f1.4G vs Sigma 50mm f1.4 quality

Testing: Longitudinal Chromatic Aberration

With lenses offering an aperture of f2.8 or larger I test for longitudinal CA (loCA, a.k.a. “axial color” or “bokeh CA”). The Sigma shows quite some magenta coloration in the foreground (left) and greenish hues in the background (right).

This also shows up in real-life shots especially under high-contrast conditions (specular highlights like sun on water or other reflecting surfaces or trees against the sky) and gets more pronounced the closer you focus. Unfortunately it is not easily corrected in post-processing, unlike lateral CAs.

 

Sigma 50mm f/1.4 ART Longitudinal Chromatic Aberration (loCA)
100% crop, 50mm, f1.4, left = foreground, right = background

 

See the Nikon AF-S 50mm f1.4G for comparison:

Nikon AF-S 50mm f1.4G Longitudinal Chromatic Aberration (loCA)
100% crop, 50mm, f1.4, left = foreground, right = background

 

Or the “non-ART” Sigma 50mm f1.4 HSM:

Sigma 50mm f1.4 HSM Longitudinal Chromatic Aberration (loCA)
100% crop, 50mm, f1.4, left = foreground, right = background

 

Of all three lenses the old Sigma 50/1.4 HSM shows the least coloration.

Sharpness and contrast

Let’s see how the lens performs in the sharpness test based on Siemens-stars compared to the Nikon 50/1.4G and Sigma’s own 50/1.4 “non-ART”.

What follows are near-center results (first column) followed by APS-C-corner results and FF-corner results on a Nikon D800. The D800 results from the APS-C-corner should be a very good approximation for performance on a 16MP APS-C sensor (like the Nikon D7000), because the pixel-pitch of both sensors are the same. But differences in the AA-filter and micro-lens-design of a D800 and a D7000 might yield different end-results.

Processing was done in Lightroom from RAW at camera standard settings. Noise-reduction is set to 0, sharpening to 70/0.5/36/10, with no extra tone, color, or saturation-adjustment. White-balance was adjusted to a neutral white and I did some exposure compensation to make the brightness match and compensate for light fall-off. CA-removal is ON. Focus was acquired manually in live-view and seperately for the center, the APS-C corner and the FF corner as all three lenses exhibit field-curvature at the shooting distance of around 2m. That is it would be impossible to shoot a perfectly flat target and achieve the maximum resolution across the sensor in one single shot.

The following are all 100% crops! Let’s start with the crops from near center:

 

Nikkor 50mm f/1.4G
with Nikon D800
100% crop from center
Sigma 50mm f/1.4 ART
with Nikon D800
100% crop from center
Sigma 50mm f/1.4
with Nikon D800
100% crop from center
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
50mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
50mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
50mm, f8.0, 100 ISO
50mm, f8.0, 100 ISO
50mm, f8.0, 100 ISO
50mm, f11, 100 ISO
50mm, f11, 100 ISO
50mm, f11, 100 ISO

 

The new Sigma is clearly ahead in center performance wide open. Its older brother comes in second place and has caught up from f2.8 onwards. From f4 all three lenses are almost indistinguishable. Peak sharpness seems to occur at f5.6 with f8 still producing excellent results and a slight softening from diffraction at f11.

Following are the crops from the APS-C corner:

 

Nikkor 50mm f/1.4G
with Nikon D800
100% crop from APS-C-corner
Sigma 50mm f/1.4 ART
with Nikon D800
100% crop from APS-C-corner
Sigma 50mm f/1.4
with Nikon D800
100% crop from APS-C-corner
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
50mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
50mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
50mm, f8.0, 100 ISO
50mm, f8.0, 100 ISO
50mm, f8.0, 100 ISO
50mm, f11, 100 ISO
50mm, f11, 100 ISO
50mm, f11, 100 ISO

 

All three lenses take at hit if you look at their performance in the APS-C corner. But again the new Sigma performs best. All three lenses show signs of astigmatism up to f4. For best results use f5.6 or f8.

Last up the most challenging crops from the corner of a 36MP full-frame 24 x 36 mm sensor:

 

Nikkor 50mm f/1.4G
with Nikon D800
100% crop from FF-corner
Sigma 50mm f/1.4 ART
with Nikon D800
100% crop from FF-corner
Sigma 50mm f/1.4
with Nikon D800
100% crop from FF-corner
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
50mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
50mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
50mm, f8.0, 100 ISO
50mm, f8.0, 100 ISO
50mm, f8.0, 100 ISO
50mm, f11, 100 ISO
50mm, f11, 100 ISO
50mm, f11, 100 ISO

 

In the corner of a full-frame sensor performance deteriorates further with spherical aberrations and coma lowering the contrast significantly and producing a haze-like effect. Through this haze the new Sigma clearly shows the best resolution. Stopping it down to f2.8 improves the situation considerably. The Nikon 50/1.4G needs to be stopped down to f4 and the older Sigma to f5.6 or even f8 to reach similar clarity.

To sum it up: The new Sigma 50/1.4 ART comfortably pulls ahead of its cheaper rivals especially on a full-frame sensor. On an APS-C / DX sensor differences are less obvious, especially compared to the Nikon.

Sigma 50mm f1.4 ART vs Nikon 58mm f1.4G vs Zeiss 55mm f1.4 Otus quality

Let’s see how the new ART fares in comparison to the more expensive competition.

 

Sigma 50mm f/1.4 ART Longitudinal Chromatic Aberration (loCA)
100% crop, 50mm, f1.4, left = foreground, right = background

 

See the Nikon AF-S 58mm f1.4G for comparison:

Nikon AF-S 58mm f1.4G Longitudinal Chromatic Aberration (loCA)
 
100% crop, 58mm, f1.4, left = foreground, right = background

 

Or the Zeiss 55mm f1.4 Otus:

Zeiss 55mm f1.4 Otus Longitudinal Chromatic Aberration (loCA)
100% crop, 55mm, f1.4, left = foreground, right = background

 

Compared with these two the Sigma 50/1.4 ART shows the heaviest colorations.

Sharpness and contrast

Let’s see how the lens performs in the sharpness test based on Siemens-stars compared to the Nikon 58/1.4G and Zeiss 55/1.4 Otus.

What follows are near-center results (first column) followed by APS-C-corner results and FF-corner results on a Nikon D800. The D800 results from the APS-C-corner should be a very good approximation for performance on a 16MP APS-C sensor (like the Nikon D7000), because the pixel-pitch of both sensors are the same. But differences in the AA-filter and micro-lens-design of a D800 and a D7000 might yield different end-results.

Processing was done in Lightroom from RAW at camera standard settings. Noise-reduction is set to 0, sharpening to 70/0.5/36/10, with no extra tone, color, or saturation-adjustment. White-balance was adjusted to a neutral white and I did some exposure compensation to make the brightness match and compensate for light fall-off. CA-removal is ON.

B.t.w.: The Zeiss Otus is the only lens in this comparison that exhibits almost no field-curvature: the crops from the center, APS-C-corner and FF-corner of each aperture were taken from the same image.

The following are all 100% crops! Let’s start with the crops from near center:

 

Nikkor 58mm f/1.4G
with Nikon D800
100% crop from center
Sigma 50mm f/1.4 ART
with Nikon D800
100% crop from center
Zeiss 55mm f/1.4 Otus
with Nikon D800
100% crop from center
58mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO
58mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
55mm, f2.0, 100 ISO
58mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
55mm, f2.8, 100 ISO
58mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
55mm, f4.0, 100 ISO
58mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
55mm, f5.6, 100 ISO
58mm, f8.0, 100 ISO
50mm, f8.0, 100 ISO
55mm, f8.0, 100 ISO
58mm, f11, 100 ISO
50mm, f11, 100 ISO
55mm, f11, 100 ISO

 

Regarding center-resolution the new Sigma ART is really hard to beat although to get the highest resolution you need to focus a bit beyond the target which leads to the magenta coloration. The Zeiss Otus is no slouch either reaching its slightly lower resolution with less longitudinal CAs. Third in place is the Nikon 58/1.4G.

Following are the crops from the APS-C corner:

 

Nikkor 58mm f/1.4G
with Nikon D800
100% crop from APS-C-corner
Sigma 50mm f/1.4 ART
with Nikon D800
100% crop from APS-C-corner
Zeiss 55mm f/1.4 Otus
with Nikon D800
100% crop from APS-C-corner
58mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO
58mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
55mm, f2.0, 100 ISO
58mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
55mm, f2.8, 100 ISO
58mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
55mm, f4.0, 100 ISO
58mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
55mm, f5.6, 100 ISO
58mm, f8.0, 100 ISO
50mm, f8.0, 100 ISO
55mm, f8.0, 100 ISO
58mm, f11, 100 ISO
50mm, f11, 100 ISO
55mm, f11, 100 ISO

 

As we’ve seen before the new Sigma ART softens up in the APS-C corner with astigmatism showing up until f4. The Nikon 58/1.4G also shows some weakness which is a bit more pronounced than from the new Sigma and is more obvious because of the coloration. You need to stop the Nikon down to f4 to get rid of this effect. At this aperture and f5.6 the Nikon has a slight lead over the new Sigma ART. But king of the hill is clearly the Zeiss Otus which shows almost no deterioration in the APS-C corner and combines this with almost perfect flatness of field.

Last up the most challenging crops from the corner of a 36MP full-frame 24 x 36 mm sensor:

 

Nikkor 58mm f/1.4G
with Nikon D800
100% crop from FF-corner
Sigma 50mm f/1.4 ART
with Nikon D800
100% crop from FF-corner
Zeiss 55mm f/1.4 Otus
with Nikon D800
100% crop from FF-corner
58mm, f1.4, 100 ISO
50mm, f1.4, 100 ISO
55mm, f1.4, 100 ISO
58mm, f2.0, 100 ISO
50mm, f2.0, 100 ISO
55mm, f2.0, 100 ISO
58mm, f2.8, 100 ISO
50mm, f2.8, 100 ISO
55mm, f2.8, 100 ISO
58mm, f4.0, 100 ISO
50mm, f4.0, 100 ISO
55mm, f4.0, 100 ISO
58mm, f5.6, 100 ISO
50mm, f5.6, 100 ISO
55mm, f5.6, 100 ISO
58mm, f8.0, 100 ISO
50mm, f8.0, 100 ISO
55mm, f8.0, 100 ISO
58mm, f11, 100 ISO
50mm, f11, 100 ISO
55mm, f11, 100 ISO

 

Now even the mighty Zeiss Otus shows some signs of stress: The resolution at f1.4 is still very impressive, but the contrast suffered somewhat. The Nikon 58/1.4G disappoints here: it suffers from coma and is pretty mushy up to f2.8. It also has the largest barrel distortion of the pack and never really loses its astigmatism even up to f11. Its smaller brother, the Nikon 50/1.4G recovers much faster in the FF corner. The new Sigma ART performs second best but needs to be stopped down to f2.8 to get good corner results.

All-in-all the Siemens-star tests establish the Zeiss Otus as the benchmark but with the new Sigma 50/1.4 ART as a close second. The Nikon 58/1.4G is a bit of a disappointment especially compared to the new Sigma: it suffers a bit from focus-shift and the resulting coloration plus astigmatism. Of the cheaper alternatives in this test the Nikon 50/1.4G delivers a surprise performance: Its center is not the sharpest but it shows a pretty even performance over the complete image circle which could be described as satisfying resolution with low contrast wide open and a very consistent improvement to very good performance when stopping down.

Sigma 50mm f1.4 ART vs Canon 50mm f1.4 vs Canon 50mm f1.2 quality

To compare real-life performance, I shot this scene with the Sigma 50mm f1.4 ART, Canon EF 50mm f1.4 and Canon EF 50mm f1.2L, all mounted on a Canon EOS 6D body.I shot the scene in Aperture Priority at every f-number, and with the 6D set to record RAW. The RAW files were then processed in Adobe Camera RAW using the same settings and with all lens profiling and corrections disabled to reveal the true optical performance of each lens.I then took crops from the areas marked by the red rectangles opposite and presented them below at 100% for comparison.I have presented my results across two tables below, detailing the relative performance in the middle and far corner of the frame. I shot the scene in RAW and processed all the images using exactly the same settings: sharpening of 50 / 0.5 / 36 / 10, white balance of 3450K, and all lens corrections disabled. With CA, distortion and vignetting correction disabled, we can really see what each lens is capable of optically.

My first table details the performance in the middle of the frame, and the sequence starts with the Canon 50mm f1.2L at f1.2. The result here is pretty good, which bodes well for subjects placed near the middle of the frame, like a typical portrait. But at f1.4 when the other two lenses join-in, it’s clear the Sigma 50mm f1.4 ART is delivering a crisper and more contrasty result. The three lenses do however begin to come very close in centre performance at f2 and by f4 they’re looking very similar – although I still think the Sigma enjoys a slightly crisper result.

So the differences are there, but are subtle in the middle of the frame. Where they really begin to differ though is in the corners and you can see that by scrolling down to the second table.

 

Canon EF 50mm f1.4 USM
Centre crop at 100%
RAW from Canon EOS 6D
Sigma 50mm f1.4 ART
Centre crop at 100%
RAW from Canon EOS 6D
Canon EF 50mm f1.2L USM
Centre crop at 100%
RAW from Canon EOS 6D
f1.2 not available
f1.2 not available
f1.2, 100 ISO
f1.4, 100 ISO
f1.4, 100 ISO
f1.4, 100 ISO
f1.8, 100 ISO
f1.8, 100 ISO
f1.8, 100 ISO
f2, 100 ISO
f2, 100 ISO
f2, 100 ISO
f2.8, 100 ISO
f2.8, 100 ISO
f2.8, 100 ISO
f4, 100 ISO
f4, 100 ISO
f4, 100 ISO
f5.6, 100 ISO
f5.6, 100 ISO
f5.6, 100 ISO
f8, 100 ISO
f8, 100 ISO
f8, 100 ISO

Sigma 50mm f1.4 ART vs Canon 50mm f1.4 vs Canon 50mm f1.2 corner sharpness

In my first table above we compared the performance in the middle of the frame, but now it’s the turn of the far corner. The things to look out for here are darkening due to vignetting, coloured fringing and softness.

The Canon EF 50mm f1.2L kicks-off the sequence at f1.2 where the corner is quite dark due to significant vignetting, and the detail quite soft. This won’t bother people who take typical portraits very much, but that’s not to say you can’t achieve superior performance. In the second row you can see all three lenses at f1.4, and a clear difference emerges. The Sigma may be suffering from some vignetting compared to later in the sequence at smaller apertures, but it’s clearly way ahead of both Canons at this point, and the detail is crisper too. In terms of corner sharpness at f1.4, the 50mm f1.4 comes next, with the EF 50mm f1.2 trailing behind, and again both Canon’s are suffering from significant vignetting.

All three benefit from closing to f1.8, particularly in terms of vignetting, although in terms of sharpness it’s still Sigma first, followed by the Canon 50mm f1.4, leaving the 1.2 last. The story improves at f2, but you need to close down by another whole stop to f2.8 to really see the vignetting eliminated. But again the sharpness ranking remains. The Canon 50mm f1.4 only begins to match the corner sharpness of the Sigma at f5.6 and f8, and while the EF 50mm f1.2 greatly improves in the corners at smaller apertures, it still falls behind the other two.

It’s no surprise to find the Sigma 50mm f1.4 ART out-performing the Canon EF 50mm f1.4, as it is after all roughly double the price and both larger and heavier too. But it is revealing that it’s also out-performing the EF 50mm f1.2L which costs considerably more. Supporters of this lens will claim it was never designed for edge to edge sharpness and that for its target use of portraiture, the quality of the bokeh is more important. So on my next page I’ll compare just that with a close look at the out-of-focus performance of each lens.

 

Canon EF 50mm f1.4 USM
Corner crop at 100%
RAW from Canon EOS 6D
Sigma 50mm f1.4 ART
Corner crop at 100%
RAW from Canon EOS 6D
Canon EF 50mm f1.2L USM
Corner crop at 100%
RAW from Canon EOS 6D
f1.2 not available
f1.2 not available
f1.2, 100 ISO
f1.4, 100 ISO
f1.4, 100 ISO
f1.4, 100 ISO
f1.8, 100 ISO
f1.8, 100 ISO
f1.8, 100 ISO
f2, 100 ISO
f2, 100 ISO
f2, 100 ISO
f2.8, 100 ISO
f2.8, 100 ISO
f2.8, 100 ISO
f4, 100 ISO
f4, 100 ISO
f4, 100 ISO
f5.6, 100 ISO
f5.6, 100 ISO
f5.6, 100 ISO
f8, 100 ISO
f8, 100 ISO
f8, 100 ISO

 

Sigma 50mm f1.4 ART vs Canon 50mm f1.4 vs Canon 50mm f1.2 bokeh

To compare the depth of field and bokeh of the Sigma 50mm f1.4 ART against the Canon EF 50mm f1.4 and EF 50mm f1.2, I shot this interior scene at every aperture setting using a Canon EOS 6D mounted on a tripod.The EOS 6D was set to its base sensitivity of 100 ISO and the lens focused on the closest part of the wire clip on the sugar jar in the lower left.On this page I’m presenting a variety of views and crops to help you evaluate and compare their performance. There’s three tables of results, so please do take a look at them all before moving on to the next section!When testing a large aperture lens, the softness and shape of the out-of-focus areas (also known as the bokeh) is often as important as the sharpness main subject. One of my favourite tests for it is to photograph a nearby subject with lights in the background. A shallow depth of field will ensure the lights are transformed into large fuzzy blobs, but as many of you know, some lenses do this more nicely than others.

Technically a point source of light should be rendered as a circular blob, but some lenses deliver more squashed oval shapes, especially towards the edges. Some photographers actually prefer this ‘cat’s eye’ effect, but optically speaking, circles are technically better. While the shape is down to personal preference, most photographers would agree they don’t like blobs with concentric rings within them, known as the onion effect. Similarly, blobs with defined outlines, especially indicating chromatic aberrations, are undesirable too. Moving away from lights, other shapes in the composition should be rendered smoothly with no distracting lines or sharp details.

With all that in mind, here’s a series of shots taken with the Sigma 50mm f1.4 ART, Canon EF 50mm f1.4 and Canon EF 50mm f1.2, all with a Canon EOS 6D mounted on a tripod. I took the shot at a selection of apertures between the maximum and f4 and have presented the results across three tables below. The first table shows the complete frame, reduced in size to fit on the page here. The second table shows a crop taken from the subject in the lower left corner, and reproduced here at 33%. Finally the third table shows a crop taken from the out-of-focus area in the upper right corner, again reproduced here at 33%. I’ll cover each table in turn.

I’ll start with the first table which again shows the complete frame, reduced to fit on the page here. You may have thought one 50mm lens would render out-of-focus areas in a similar way to another, and that any differences would become invisible at the scale below, but it’s surprising just how much each model has stamped its visible mark on this subject.

The Canon EF 50mm f1.2 kicks-off the sequence at f1.2, and certainly this aperture is delivering a shallower depth of field with larger out-of-focus shapes than any of the lenses at f1.4 in the row immediately below. But you’ll notice the shapes of the out-of-focus lights vary between models with both Canon lenses exhibiting much more of a squashed cat’s eye effect than the Sigma. Technically speaking, a rounder shape is optically superior, although some simply prefer the look of the squashed ovals.

Look closely at the samples from the EF 50mm f1.2 and you’ll also notice how some of the shapes have become cropped-off towards the top of the frame. This clipping effect is often seen on very bright aperture lenses and with the DSLR’s mirror box often to blame. Whatever the reason though, the clipping is visible on the 50mm f1.2 pretty much until closed to f2.8, whereas it’s not apparent on the Canon EF 50mm f1.4 or Sigma 50mm f1.4 ART.

As the aperture is closed you’ll also notice the optical impact of the aperture blades: their number and shape. Even at this reduced size, I’d say the eight blade iris of both Canon lenses is clearly visible from f1.8 onwards, rendering the blobs into octagons with relatively defined edges. The nine-blade system of the Sigma is however much more discreet, with the extra blade and curved shape lending a much more circular shape to the blobs. Look closely and you’ll still see clear nonagons, but they’re more subtle and rounded than the octagons on the two Canons here.

Amazingly, all of this is visible at the tiny scale below. Now let’s see what happens when you look closer at the focused and out of focus areas. Scroll down for a comparison.

 

Canon EF 50mm f1.4 USM
Full image reduced to fit frame
JPEG from Canon EOS 6D
Sigma 50mm f1.4 ART
Full image reduced to fit frame
JPEG from Canon EOS 6D
Canon EF 50mm f1.2L USM
Full image reduced to fit frame
JPEG from Canon EOS 6D
f1.2 not available
f1.2 not available
f1.2, 100 ISO
f1.4, 100 ISO
f1.4, 100 ISO
f1.4, 100 ISO
f1.8, 100 ISO
f1.8, 100 ISO
f1.8, 100 ISO
f2, 100 ISO
f2, 100 ISO
f2, 100 ISO
f2.8, 100 ISO
f2.8, 100 ISO
f2.8, 100 ISO
f4, 100 ISO
f4, 100 ISO
f4, 100 ISO

Sigma 50mm f1.4 ART vs Canon 50mm f1.4 vs Canon 50mm f1.2 bokeh close-up

In my second table below I’ve taken a crop of the area I focused on, marked by the red rectangle in the lower left corner of the image opposite. The crops represent a 33% reproduction. The subject was close but within the minimum focusing distance for each lens.

In the crops below I think it’s immediately apparent that the Sigma 50mm f1.4 ART is pretty sharp even at f1.4, whereas its Canon rivals are not. This is with the crops viewed at 33%, and the difference is even more obvious at 100%. It’s not really until the Canons are both closed to around f2.8 that they can deliver a similar degree of sharpness and contrast on a subject in the corner at close range. I repeated the test several times to ensure the focus was spot-on and I can confirm the crops below are all in focus.

The Canons perform much better in the middle at larger apertures, which will be fine if you’re shooting portraits, but if you’re shooting anything with detail in the corners at close range, the Sigma visibly out-performs the Canon EF 50mm f1.4 and EF 50mm f1.2 at apertures larger than f4.

Now scroll down further to take a closer look at their out-of-focus areas, or skip to my Sigma 50mm f1.4 ART sample images.

Canon EF 50mm f1.4 USM
Crop from subject at 33%
JPEG from Canon EOS 6D
Sigma 50mm f1.4 ART
Crop from subject at 33%
JPEG from Canon EOS 6D
Canon EF 50mm f1.2L USM
Crop from subject at 33%
JPEG from Canon EOS 6D
f1.2 not available
f1.2 not available
f1.2, 100 ISO
f1.4, 100 ISO
f1.4, 100 ISO
f1.4, 100 ISO
f1.8, 100 ISO
f1.8, 100 ISO
f1.8, 100 ISO
f2, 100 ISO
f2, 100 ISO
f2, 100 ISO
f2.8, 100 ISO
f2.8, 100 ISO
f2.8, 100 ISO
f4, 100 ISO
f4, 100 ISO
f4, 100 ISO

Sigma 50mm f1.4 ART vs Canon 50mm f1.4 vs Canon 50mm f1.2 bokeh close-up

In the table below I’ve taken crops from the area marked by the rectangle in the upper right of the image for a closer look at the out-of-focus areas. I’ve shrunk the crops to represent a 33% reproduction here.

In the crops below, the cat’s eye / squashed oval effect is again more apparent on the two Canon lenses, although the Sigma isn’t completely immune in the far corners. If you look back at the first table with the complete frames though, you can see how the Sigma avoids the effect away from the far corner, whereas they’re visible across more of the frame on the Canons.

The clipped shape is also more apparent on the crops from the 50mm f1.2, and to me it’s quite distracting and a downside of this lens design on a DSLR. I also think the Sigma maintains a more circular shape as the aperture is closed. The good news is all three avoid the onion-ring effect of concentric rings inside the blobs, and there’s no coloured fringing to complain about on any of them either. But ultimately I think the bokeh is smoother and better-rendered on the Sigma, and the in-focus areas are sharper too. This is expected when compared against the EF 50mm f1.4 which is less than half the price, but impressive compared to the EF 50mm f1.2 which is comfortably more expensive.

 

Canon EF 50mm f1.4 USM
Crop from subject at 33%
JPEG from Canon EOS 6D
Sigma 50mm f1.4 ART
Crop from subject at 33%
JPEG from Canon EOS 6D
Canon EF 50mm f1.2L USM
Crop from subject at 33%
JPEG from Canon EOS 6D
f1.2 not available
f1.2 not available
f1.2, 100 ISO
f1.4, 100 ISO
f1.4, 100 ISO
f1.4, 100 ISO
f1.8, 100 ISO
f1.8, 100 ISO
f1.8, 100 ISO
f2, 100 ISO
f2, 100 ISO
f2, 100 ISO
f2.8, 100 ISO
f2.8, 100 ISO
f2.8, 100 ISO
f4, 100 ISO
f4, 100 ISO
f4, 100 ISO

 

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