IMovie 11 DV video import quality

I have a lot of VHS and mini DV tapes I want to convert to digital to preserve them. I have been frustrated with PC issues for the past 15 years and I just made the switch from PC to Mac. All I have ever heard about is the quality of video editing capabilities of a Mac! So I bought a new Mac mini and was planning to get the Elgato video capture cable for the VHS tapes, but thought I would try the DV tapes first. I Hooked the firewire up to my JVC mini DV camera and was anticipating a great import into IMovie only to be sooo disappointed by the grainy dingy results. The transfer quality is better in my dinosaur HP using Arcsoft Showbiz! From what I have been reading this may be a problem with the new IMovie version. Mine is a new Mac Mini so I believe it is IMovie 11. I was hoping someone could tell me how to change some settings but I think I may have made a mistake switching to a Mac! Can anyone help me here???
Signed, very disappointed and frustrated New Mac User