Lens review

Olympus M.Zuiko Digital ED 45 mm f/1.2 PRO

21 February 2018
Maciej Latałło

4. Image resolution

For many years our Micro 4/3 optics tests were based on the Olympus E-PL1. Some time ago we’ve also started to test lenses using the Olympus OM-D E-M5 Mark II as we felt the time has come for changes. That’s how we found out that between sensors of those two bodies there is a very small difference, amounting to 5-7 lpmm at most, to the advantage of the newer one with a higher pixel count. Mind you that difference is possible to notice only in the wide area of the maximum relative aperture and it decreases when you employ apertures limited strongly by diffraction.

At the beginning we established that, in the case of OM-D E-M5 Mark II – based tests, the best fixed focal length lenses are able to reach 80-85 lpmm and the decency level we set near 47-49 lpmm. Of course we clearly indicated that these values could change with the enlargement of our tests database. The last resolution record achieved by the Panasonic Leica DG Elmarit 200 mm f/2.8 POWER O.I.S.,which maximum result exceeded 91 lpmm, makes that decision fully justified. Currently we should say that the decency level is set within 48-50 mm range and the best fixed focal primes should be able to get to a level of about 85 lpmm or higher.

Let’s check how the performance of the Olympus M.Zuiko Digital ED 45 mm f/1.2 PRO compares – the graph below shows its results in the centre and on the edge of the frame.

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Olympus M.Zuiko Digital ED 45 mm f/1.2 PRO - Image resolution

When it comes to resolution records, you get the biggest chance of breaking them with a very fast lenses because they get more space for limiting effectively optical aberrations as you stop them down. Most aberrations disappear after stopping down the aperture by even 3 EV and you still find yourself far from a significant diffraction limit. What’s more, lenses with angles of view of just more than several dozen degrees have big chances to reach record-breaking values. You don’t have to employ big elements in them so there are no significant curvatures like in wide angle lenses or big optical element like in a case of long tele photo lenses of good aperture fastness. As a result these are quite simple constructions to produce and to correct properly.

As you see, the Olympus M.Zuiko Digital ED 45 mm f/1.2 PRO seems to be predestined to break resolution records and indeed, it does so with utter ease. It starts quite tamely because at the maximum relative aperture the MTFs reach 62 lpmm. Still it would be difficult to complain about such a result because you land noticeably above the decency level and it is better than the result of the Olympus 1.2/25. On stopping down the aperture the resolution increases sharply and by f/2.0, f/2.8, and f/4.0 you get brilliant values of 93.1, 96.3, and 92.0 lpmm respectively. Practically each of these could be a new resolution record, imagine that!

It would be difficult to find any fault with the resolution on the edge of the frame. Even by f/1.2 you get 49 lpmm meaning a quite decent image quality. On slight stopping down to f/1.4 the MTFs increase to over 53 lpmm and the peak of the performance you see by f/4.0 with excellent values, exceeding 80 lpmm.

To sum up the Olympus M.Zuiko Digital ED 45 mm f/1.2 PRO performs exactly as well as a top-end fast telephoto lens should perform. You get brilliant results both in the frame centre and on its edge and the resolution record is broken with a surplus.

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 RAW files we used for the analysis above.

Olympus E-M5 II, JPEG, f/1.2
Olympus M.Zuiko Digital ED 45 mm f/1.2 PRO - Image resolution
Olympus E-M5 II, JPEG, f/2.8
Olympus M.Zuiko Digital ED 45 mm f/1.2 PRO - Image resolution