I carried my old E-1 with a heavy lens, from the strap, off and on. Eventually, it caused major wearing of the eyelets. This isn't a problem with the slotted steel eyelets of cheaper DSLRs, but the old chrome over brass (be nice if they were stainless steel) eyelets are subject to wear. However, the camera lens mount is another issue. I would hang a heavy lens off the E-1's mount without a second thought because the camera body was solid. Would you hang 600gms from an E-M5? I picked up a Nikon 35-70mm f2.8 lens and that is what it weights.