M42 manual focus lenses

My father lent me four manual focus lenses, which I intend to test during the next couple of days/weeks:

tiger

Auto Revuenon 55 mm f/1.4
Hanimar 55 mm f/1.4 (looks very similar to the previous)
Meyer Görlitz Primoplan 58 mm f/1.9
Carl Zeiss Jena Tessar 50 mm f/2.8

I do have an awfully hard time focusing with these screwed to my EOS 400D, expecially under low light conditions, open aperture and short DOF. More than 70% out of focus so far. But I like the feel of it very much. Since my first SLR is the EOS 400D I still own now, this experience is absolutely new to me.

The tiger to the left was shot with the Auto Revuenon. No post processing.