A Super-Takumar 55mm f1.8 M42 lens vs a Super-Takumar 50mm f1.4 M42 lens adapted for the micro four-thirds mount. Images below are taken with an Olympus E-M10 body.
Stepped down across all stops in both cases, with the focus at minimum distance. ISO and shutter speed are set to automatic.
Super-Takumar 50mm f1.4 M42
Super-Takumar 55mm f1.8 M42