You asked
Is the voigtl nder apo lanthar 28mm f 2 aspherical hard to focus manually?
The site doesn't say how easy or hard this lens is to focus by hand. What it does say is that the Voigtländer APO-Lanthar 28mm f/2 Aspherical is manual focus only, with no autofocus. It fits Sony E, Nikon Z and Leica M mounts, and on full frame it frames as a true 28mm.
If you're weighing that up, the Street page explains why a fixed focal length suits shooters who like to pre-visualise the frame, and the Lenses page covers manual-focus glass more generally. If you tell me what you plan to shoot, I can help you decide whether manual focus fits that work.
Written by Claude from this site's pages.