Lens review

Sony 35 mm f/1.4G

2 July 2009
Szymon Starczewski

4. Image resolution

As it was mentioned in the introduction, the Sony 35G was tested on a 10 megapixels APS-C detector (Sony A100) and on a full frame of a 24 megapixels A900. In the case of the latter camera, the pixels density is as 11 megapixels on an ASP-C detector; it would indicate that the MTF results should be on the similar level. One look at the chart below, showing the frame center performance proves that the differences are significant.

Sony 35 mm f/1.4G - Image resolution

The values for Sony A900 are definitely lower than for A100 which suggest that the A900 pixels works less efficiently. On one hand it’s quite understandable, because the CCD matrices, while working on lower sensitivities usually showed a bit better results than the CMOS sensors. On the other hand, the differences are really huge which indicates the problems the A900 has when it comes to a good contrast and/or big number of details. The place for such an analysis it is in an A900 test, though, so we will stop here and return to the discussion about the optical properties of the lens.

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In both cases, the performance at wide aperture is weak. A level a bit over 20 lpmm is far from the result of 30 lpmm, which we consider acceptable. You can reach it with this lens only from f/2.0 onwards and from that point the lens gives us sharp pictures, which become even very sharp by f/2.8 –11 range. The results, although good, are not outstanding and we would expect something better from the prime which cost almost 5000 zl. It’s enough to remind you that the best prime lenses, tested on 10 megapixels sensors A100 or D200 had definitely better results, near 47 lpmm. In the case of Sony it’s just 44 lpmm.

When we look at the picture below, we see that there are even more troubles in the frame edge.

Sony 35 mm f/1.4G - Image resolution

By f/1.4 – 2.8 the picture quality is low, only above these values the lens, working on APS-C, starts giving sharp pictures. Here we can also observe additional differences between a small sensor and a full frame, which, because of the biggest detector, is more demanding in the frame edge. That’s why, while working on A900, the lens never achieves the decency level and better pictures are only possible in the aperture range of f/5.6-16.

At the end we traditionally present the excerpts of the test chart pictures, based on JPEG files saved along with RAW files. We show the frame center results for A100 and frame corner results for A900. If you compare these pictures, please, take into account the fact, that an A100 on standard settings, sharpens JPEG files better than an A900.

Sony 35 mm f/1.4G - Image resolution

Sony 35 mm f/1.4G - Image resolution