You'll need an M42 adapter for any EOS mount camera. Yes, Ebay is where you can purchase the lens as well as the adapter, although I would recommend purchasing the adapter through Amazon. Per your info, there are various versions of the Helios 44M. I'd recommend the 44M-4 version. If you want the best Helios version with great contrast and better swirly bokeh, I'd recommend purchasing the more expensive 77M versions.