Sigma 50mm f/1.4 Art Sharpness and Bokeh Comparison

While initially testing the Sigma 50mm f/1.4 Art lens for our in-depth review, we only had access to the Canon version of the lens (since it came out first), so we could not provide comparison results to other similar focal length Nikon prime lenses. Thanks to our friends at B&H Photo Video, we recently received two copies of the lens for the Nikon F mount to finally complete the review. We also obtained the older version of the lens, the Sigma 50mm f/1.4 EX DG HSM, along with the Nikon 50mm f/1.4G and Nikon 58mm f/1.4G lenses for comparisons. Unfortunately, the Zeiss Otus 55mm f/1.4 we tested was not available at the time and we could not include it in the below bokeh comparisons, although our usual sharpness tests were carried out and those are included in this article.

Before we talk about bokeh characteristics of the above-mentioned lenses, let’s first take a look at the sharpness performance. As usual, we used Imatest software to measure the resolving power of lenses.

1) Imatest Score System Overhaul

While looking at the below Imatest results, you might notice that the scores have changed from our normal range. This is due to the fact that we have decided to change our lens testing methods for more accuracy and consistency of results. Previously, we relied on Adobe Camera RAW engine to process images, thinking that it was a more realistic approach, as many photographers heavily use Adobe software like Photoshop and Lightroom for post-processing images. However, our experience with the Adobe’s RAW processing engine has shown that Adobe can be quite unreliable and inconsistent when it comes to processing RAW files, particularly when dealing with different manufacturers. Silent application of lens corrections and bad handling of Fuji RAW files were the reason why we’ve decided to permanently switch to DCRaw software for demosaicing RAW files. The results have been much more consistent and accurate.

In addition, we want our readers to be able to compare our Imatest scores to other review sites on the Internet that also utilize Imatest software and the same cameras. We will provide instructions on how to do that in a separate article, where we will also shed some light on our lens testing procedures.

Since we have tested many lenses so far, we ask our readers to be patient while we transition all the reviews to the new format. In addition, we are also updating each review, so that the provided image samples are of high resolution (minimum 2048 pixels on the long edge) for newer high resolution monitors, tablets and other hand-held devices.

Let’s take a close look at how the Sigma 50mm f/1.4 Art performs in terms of sharpness and bokeh and compare it to other fast f/1.4 lenses in the similar focal length range.

2) Sigma 50mm f/1.4 DG HSM Art vs Sigma 50mm f/1.4 EX DG HSM

How different is the new Sigma 50mm f/1.4 Art compared to the older Sigma 50mm f/1.4 version? Let’s take a quick look at the performance benchmarks:

Looking at the above charts, it is immediately clear that the older Sigma 50mm f/1.4 EX DG HSM simply does not stand a chance against the new 50mm f/1.4 Art. The older version is much worse at the maximum aperture and does not have near as good of sharpness when stopped down. This is expected, since the optical formula is very different between these lenses.

3) Sigma 50mm f/1.4 DG HSM Art vs Nikon 50mm f/1.4G

What about the Nikon 50mm f/1.4G lens? Let’s compare the two:

Although the Nikon 50mm f/1.4G starts out better than the older Sigma 50mm f/1.4 EX DG HSM, its performance is nowhere close to what the Sigma 50mm f/1.4 Art is capable of, even stopped down to f/8.0.

4) Sigma 50mm f/1.4 DG HSM Art vs Zeiss Otus 55mm f/1.4

Here is how the amazing Zeiss Otus 55mm f/1.4 compares to the Sigma 50mm f/1.4 Art:

Interestingly, the Sigma 50mm f/1.4 Art sample I tested was a phenomenal copy, while the Zeiss Otus 55mm f/1.4 seems like a really bad sample, since it cannot compete with the Sigma even when stopped down. I will be requesting another copy of this lens to do a more thorough analysis, because it just does not seem right. Exotic lenses are expensive and I wonder what happened to this copy after all the rigorous testing it went through at the factory…

Unfortunately, the two Sigma 50mm f/1.4 Art lenses we’ve tested did not reveal consistent results. Although we always use the best scores a lens can produce, the first sample of the Sigma Art produced inferior results, by up to 12%. This shows that your mileage with the Sigma 50mm f/1.4 could vary due to inferior QA / sample variation.

5) Sigma 50mm f/1.4 DG HSM Art vs Nikon 58mm f/1.4G

Lastly, let’s take a look at how the Sigma 50mm f/1.4 Art fares against the Nikon 58mm f/1.4G:

As we have pointed out in our Nikon 58mm f/1.4G review, the lens is not about sharpness and the above chart reflects that. Not only is the Nikon 58mm f/1.4G noticeably softer wide open, it also has quite poor mid-frame and corner performance due to its wavy / sombrero field curvature. Its corner performance stays poor even when stopped down. Clearly, if you are looking for ultimate sharpness, you should skip the 58mm f/1.4G…

6) Sigma 50mm f/1.4 Art Bokeh Comparison

The bokeh rendering capability of the lens is quite pleasing for a 50mm prime. Highlight shapes do show defined transitions, but they do not look distracting as on some lenses. The dreaded onion-shaped bokeh that I showed on the Sigma 35mm f/1.4 Art is barely visible when photographing extremely bright points of light. Below are two comparisons that illustrate bokeh rendering capabilities of the following lenses: Sigma 50mm f/1.4 DG HSM Art, Sigma 50mm f/1.4 EX DG HSM, Nikon 50mm f/1.4G and Nikon 58mm f/1.4G. Here is the first comparison that shows bright highlights:

Based on my subjective opinion and preference, I would rank the above lenses in bokeh performance in the following order, from best to last: Nikon 58mm f/1.4G, Sigma 50mm f/1.4 EX DG HSM, Sigma 50mm f/1.4 Art, Nikon 50mm f/1.4G. The Nikon 58mm f/1.4G clearly shows the least defined borders and very smooth transitions everywhere, so it is my #1 choice here.

What about background transitions? Let’s take a look at another example:

Once again, the smoothest of the bunch is the Nikon 58mm f/1.4G, followed by the older Sigma 50mm f/1.4, then the Sigma 50mm f/1.4 Art and the Nikon 50mm f/1.4G.

Looks like the older Sigma 50mm f/1.4 has a superior bokeh construction, although its sharpness is nowhere as good as the new 50mm f/1.4 Art.

7) Summary

Based on the above sharpness comparisons, it is clear that the Sigma 50mm f/1.4 Art is a superb choice when compared to the competition. The lens heavily outperforms its predecessor and both Nikon 50mm f/1.4G and 58mm f/1.4G lenses, which is very impressive. The only area where the Sigma Art shows inferior results is in its bokeh performance – the older Sigma 50mm f/1.4 EX DG HSM seems better in this regard, thanks to smoother rendering of highlights and other out of focus regions.

Congrats to Sigma for creating yet another winner. I hope Sigma will continue to impress us with more superb lenses like this in the future. The rumored Sigma 85mm f/1.4 Art might have a tough time competing with the Nikon 85mm f/1.4G and 85mm f/1.8G lenses, as they are already amazing…

The above information was incorporated into our Sigma 50mm f/1.4 Art review