RF 50mm f1.8 STM is working well. In our laboratories, the lens reveals a beautiful bell curve which is a delight to see. Diffraction appears after f / 11 and higher values are not recommended. At the other end of the line, the full aperture at f / 1.8 is also lagged. This is not necessarily surprising, causing damage to the f / 4 along the edges.
A very good dive at f / 5.6
In short, it is at f / 4 that the diaphragm needs to be closed to benefit from the best image quality, which we will keep at f / 8. For those who want to set the aperture directly to the best value, we recommend setting it to f / 5.6, an aperture that provides the most tangible results, at the center and at the edges.