The 55mm F1.8 is known as a very sharp lens all over the field. The tests underneath show that one lens gets blurred on the left side of the field, whereas the other lens gets blurred on the right side of the field. The amount of blur is visible in 50 or 100% crops, but will not be so severe that it causes problems in practice. THe blurring is visible up to f5.6, and at f8.0 hardly any differences can be spotted. For a €999 lens one expects a better overall field performance though.

Bookshelf
For the bookshelf, in the centre both lenses are sharp (some small variations in color fringing can be seen per photo). But the difference between the (selected) bottom-left and top-right (crops) is quite significant. One lens is blurred on the left side, whereas the other lens is blurred on the right side.


Cityscape
For the cityscape, in the centre both lenses are sharp as well (some variations due to the weather conditions, it was raining very badly, I even took these pictures through the window, which still gives an amazing sharpness - repeated again, it is the relative comparison that is important here, not the absolute amount of sharpness). The difference between the (selected)left and right (crops) is quite visible. One lens is blurred on the left side, whereas the other lens is blurred on the right side. One example has bee added to show it is not blurred relatively anymore from f8.0 onwards.

Summary

It is clear that the first sample is strong in the centre, and on the left side, with a bit of weakness on the right side at open apertures. The second sample is a bit less sharp in the centre, and not so sharp at open apertures. Overall, the first sample is a bit stronger. The results are summarizes in the tables below.

Detailed examples

Use the filter button below to select which cases you want to see and compare in detail (the buttons will limit the selection), and use the slider to compare the 2 lens samples.