The best low light lense for the gh5, and one of the sharpest lense there is. Use the speed booster to connect it to the gh5. And enjoy an extra stop of light making it f1.2 lense, this lense is like a tank heavy reliable and has amazing picture quality. The brother to the sigma 18-35. Beautiful and big lense. You cannot go wrong with this for your filimgendevours. Full frame picture and broken on cropped sensor.