Last summer while rummaging through the attic I ended up finding a Helios 44-M lens. It`s an old russian lens first made in 1958 in Soviet Union.
Short specifications : 58mm with F from 2 to 16 with aperture and manual focus.
So my first thought was to see if I could mount this to my Canon 40d . After some research on the internet, I found a way with an aluminum adapter ring.
In one word this lens is awesome. I work with a 50mm f1.4 from canon but this old lens is something that touches the soul. It may be just the overall quality of the lens or the feeling you have when you use it.