You asked
What lenses should I buy for the om system om 1 mark ii?
The OM-1 Mark II is a wildlife favourite, so I'd build around one fast zoom and one long lens. If you're not sure what you'll shoot, start with the Olympus M.Zuiko 12-45mm f/4 PRO, which frames like 24-90mm on full frame and covers most everyday shooting.
For wildlife and sport, I'd go for the Olympus M.Zuiko 40-150mm f/2.8 PRO, which works like 80-300mm on full frame and is fast enough for low light. If you want more reach, the OM System M.Zuiko 150-600mm f/5-6.3 IS goes out to 300-1200mm equivalent.
For a small, cheap extra for low light and portraits, the Olympus M.Zuiko 25mm f/1.8 is a sensible prime.
You can check other focal lengths with the focal length converter. Full lens list for this body: OM System OM-1 Mark II.
Written by Claude from this site's pages.