Re: MF Zoom with the Pen
If they are zoom lenses, you rotate the zoom ring or push it forward/back depending on wheter it is a 2 ring zoom or 1 ring zoom.
I suspect your Hexanon lenses are not zoom lenses if you cannot see an obvious way of zooming them.
My father had an early Konica AutoReflex T camera and this was the first SLR I spend any amount of undue stiffness or slack in the focus ring but such problems do occur from time to time. If all are similar, then I suspect that it is that you are not use to using a focus ring with a mechanical link to the glass. Some focus by wire rings are too lose for my liking.