We’ve recently been trying out some vintage M42 mount lenses on the 5D Mark II. The images below were taken with a Pentacon 135mm f/2.8 manual focus lens. I think it’s gorgeous!
If you’re interested, just visit your local online second hand retailer (aka eBay). You’ll need an adapter first, preferably with a chip on it so that your camera can show focus and then the world of M42 lenses is yours to explore!