Sigma C 15 mm f/1.4 DC review

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Sigma C 15 mm f/1.4 DC

21 May 2026

Maciej Latałło

4. Image resolution

Our resolution test (resolution meaning the MTF50 function values) of Sony FE lenses is based on RAW files from the 42.4 Mpix sensor of the Sony A7R II, the Sony A7R III, or the Sony A7R IIIa cameras. In the case of this kind of detector, the decency level we set is about 39-41 lpmm and the best fixed focal lenses have been able to slightly exceed 80 lpmm. Record breaking lenses can get as high as over 85 lpmm or even 90 lpmm.So far, our list of such record-breakers features the Sigma A 17-40 mm f/1.8 DC (89.9 lpmm), the Meike 85 mm f/1.4 FF STM (90.2 lpmm) and the Sony FE 50 mm f/1.4 GM (90.9 lpmm).

Let's check how the Sigma C 15 mm f/1.4 DC compares here – its results in the frame centre and on the edges presents a graph below.

Sigma C 15 mm f/1.4 DC - Image resolution

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When it comes to the frame centre you can say without any doubt that you deal with an excellent lens. The maximum level, exceeding slightly 86 lpmm, is, within the margin of error, the same as the level of the 12 mm device, tested by us not so long ago, but the 15 mm lens is better at the maximum relative aperture. Overall these are the best results we've seen so far when it comes to the Sigma lenses line-up.

The results on the edge of the frame lag behind the values from the centre. It's obvious the small dimensions of the lens make themselves felt. On the other hand you shouldn't complain about it because even at the maximum relative aperture, images are of good quality and on stopping down, the results reach very good values of over 60 lpmm. In this case the 15 mm device is better at every aperture than the 12 mm lens but it loses to the 23 mm model that could reach almost 70 lpmm. Of course the 23 mm lens had it easier because of a much narrower field of view.

How the tested lens compare to its predecessor and the direct rival, the Sony 1.4/15G? I think these are the most important questions this chapter should answer. The graph below presents a comparison between these three models in the frame centre.

As you can notice, the new Sigma prevails here without any problems. An improved performance compared to the predecessor was only predictable because such a renowned company as Sigma wouldn't shoot themselves in the foot, producing a new model that is weaker than the old one. Still, the duel with the Sony wasn't so obvious and yet here the Sigma, a cheaper lens, prevails as well.

Perhaps the victory in the centre was paid for with weaker results on the edges? Let's glance at another graph and find out.

The order remains exactly the same – the new Sigma is the leader, then comes the most expensive Sony and finally the almost 10-year-old 16 mm lens.

As you can see the new Sigma C 15 mm f/1.4 DC performs exceedingly well and, when it comes to the resolution, it is a completely recommendable instrument. A round of applause!

At the end of this part of the test, traditionally we present crops taken from photos of our resolution testing chart, saved in JPEG format along with RAW files we used for the analysis above.

Sony A7R IIIa, JPEG, f/1.4