Before buying, check two things first: compatibility and condition.

Make sure the lens mount can actually be adapted to your camera body. Mirrorless cameras are often easiest for vintage lenses because of their short flange distance, but some adapters may limit focus, including infinity focus.

Then inspect operation and optics:

• Focus ring: should turn smoothly, not bind or feel gritty
• Aperture ring/levers: should move properly
• Aperture blades: should open/close cleanly and not stick
• Glass: look for fungus, haze, heavy dust, scratches, or separation

For “restoration,” light external cleaning is one thing; internal servicing is another. Proper lens servicing is closer to repair work than simple cleaning: you may need service information, the correct tools, and experience. Some lenses are straightforward, others are difficult, and it’s easy to damage optics or mechanisms if you disassemble them without knowing what you’re doing.

If the lens has fungus, sticky blades, stiffness, or internal issues, the safest route is usually a good CLA/repair technician. If you want to learn DIY servicing, research the exact lens model first, find manuals/videos, and understand the process before opening it.