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Lens review

Carl Zeiss Otus 85 mm f/1.4

13 October 2014
Szymon Starczewski

4. Image resolution

The resolution test of the Zeiss Otus 1.4/85 was based on RAW files from the Canon EOS 5D MkIII. That camera is a successor of our old, run-down EOS 1Ds MkIII. Fortunately the pixel density of both sensors is almost the same so the MTF values almost identical. In both cases the decency level is situated near 30-32 lpmm and the best fixed-focus lenses can reach as high as 44-47 lpmm.

The graph below shows the performance of the tested lens in the frame centre, on the edge of the APS-C sensor and on the edge of full frame.

Carl Zeiss Otus 85 mm f/1.4 - Image resolution

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In fact the only commentary should concern the results at the maximum relative aperture. Many lenses, tested by us, have been assessed by f/1.4 very well if only they managed to exceed a level of 30 lpmm; the Otus by f/1.4 reaches almost 40 lpmm. Such a result is a peak of possibilities of many older ‘primes’, mind you only after some significant stopping down. The conclusion is simple - the Otus doesn’t have to be stopped down at all in order to produce exceedingly sharp photos.

Still dealing with such results you cannot be too concise – let me cherish them properly because they don’t happen very often. Already by f/2.0 the Otus 1.4/85 is able to reach an excellent level and in the range from f/2.8 to f/4.0 it would be difficult not to call its performance outstanding. By f/4.0 you deal with a full frame Canon sensor resolution record. Up to now the best results, amounting to 47.3-47.4 lpmm, belonged to the new Sigmas A 1.4/35 and the 1.4/50. The Otus managed to beat them by a hair’s breadth (0.3 lpmm) but still.

The performance on the edge of the frame can be described in similar manner. The images you get there are not only useful but downright good, even with the lens wide open. On stopping down the lens exceeds a level of 40 lpmm even on the very edge of full frame – a sensational result indeed!

At the end of this chapter we present crops taken from the frame centre of our testing chart photos; they were saved as JPEG files along with RAW files, used for generating the graphs above.

Carl Zeiss Otus 85 mm f/1.4 - Image resolution