You asked
Is the voigtl nder apo lanthar 50mm f 2 aspherical hard to focus manually?
Yes, it's manual focus only. The APO-Lanthar 50mm f/2 has no autofocus, so you'll be turning the focus ring yourself every time. I don't have a note on how easy or fiddly its focus ring is, so I won't guess at that.
If you've shot with manual lenses before, it's a reasonable match. If you haven't, the Lenses guide explains why old manual-focus glass is a cheap, fun way to learn, since mirrorless mounts make adapting it simple. Then pick a body from the list on the lens page that suits how you shoot.
Written by Claude from this site's pages.