Not many digital cameras currently offer a focusing screen so in my past experience it was difficult to focus using a manual lens. I had to take many shots at various focus distances and hope that I will end up with a sharp one. This was on a Nikon D5100 with a non-motorized lens. I don't know if you had to do the same here but it came out good.
I'm using a Sony NEX-C3, and Sony offers a few tricks that make manual focusing easy, especially on their cameras with electronic viewfinders what this camera has is a thing called focus peaking, which is basically like a manual contrast detection AF system where it highlights on the screen areas with the highest contrast (your in focus areas). The other thing it has is focus magnification where you can see a magnified view of your image in live view and pinpoint your focus. Using both of these tools lets me get very accurate manual focus