The biggest saving in terms of weight isn’t the bodies. It’s the glass where you save real weight. A couple of good examples. The 12-40 f2.8 Pro lens (24-80mm 35mm equivalent) weigh in at 382g. The Nikon 24-70 f2.8 is 900g
This is the Olympus 45mm f1.8 lens. Not their Pro lens but part of their Premium range. It’s a 90mm portrait (35mm equivalent) lens. it only weighs 116g!!
The closest Nikon lens is the Nikon 85mm f1.8 G AF-S Lens which weighs 350g.
They’re both good lenses, but the olympus, for its size and cost is mind blowing.
The picture left was taken with the 45mm f 1.8 on the OM-1 Mk 1. It’s straight out of the camera with no retouches. It is converted from the RAW file.
This is why I love Olympus and M43. It’s why I can’t go back, despite the new Nikon Z6 being one of the best cameras ever made. I just dig light.