Lens review

Sigma C 45 mm f/2.8 DG DN

28 February 2020
Maciej Lata³³o

4. Image resolution

The resolution test (resolution meaning MTF50 function value) of the Sigma C 45 mm f/2.8 DG DN was based on RAW files from the Sony A7R II. In the case of that mirrorless camera the decency level we set about 39-41 lpmm and some of the best fixed-focal lenses have been able to exceed 70 lpmm; so far the Samyang AF 85 mm f/1.4 FE (76.5 lpmm) and the Voigtlander Apo-Lanthar 65 mm f/2 Aspherical 1:2 Macro (78.5 lpmm) have fared the best.

Let's check how the tested Sigma C 45 mm f/2.8 DG DN compares – its results in the frame centre and on edges of APS-C and full frame are presented below.

Sigma C 45 mm f/2.8 DG DN - Image resolution

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Our description of results should be started with a very interesting performance at the maximum relative aperture where the values are very similar to each other, no matter what frame part you take into consideration. They are also on the borderline of the decency level. Fortunately, in the frame centre, image quality improves very quickly. On stopping down and by f/4.0 the lens reaches over 60 lpmm and by f/5.6 it gets to almost 65 lpmm. It's true, we are far away from record values but nobody should expect them from a simple f/2.8 lens.

You should rather stack it up against other 2.8/35 type constructions which we've already tested on the same body. The tested Sigma compares very favourably to the expensive Sony Zeiss Sonnar 2.8/35, which maximum result was just 62 lpmm. The Samyang AF 35 mm f/2.8 FE is a tad better than the Zeiss, reaching over 63 lpmm, but it isn't able to win a resolution duel with Sigma either.

What about the edge of the APS-C sensor? The Sigma is still able to outdistance its rivals as its maximum results exceed 56 lpmm when the Samyang wasn't able to reach 53 lpmm and the Zeiss had problems with getting higher than 40 lpmm. On the edge of full frame you see that order repeated. The Sigma defeats the Samyang and simply outclasses the expensive Zeiss.

The overall image is completely positive: not only the Sigma C 45 mm f/2.8 DG DN is able to provide sharp images across the frame almost from the maximum relative aperture but also it fares noticeably better than similar mirrorless constructions produced by rival companies.

At the end of this chapter, traditionally, we present crops taken from photos of our resolution testing chart which were saved as JPEG files along with RAW files we used for the analysis above.

A7R II, JPEG, 45 mm, f/2.8
Sigma C 45 mm f/2.8 DG DN - Image resolution
A7R II, JPEG, 45 mm, f/5.6
Sigma C 45 mm f/2.8 DG DN - Image resolution