I've got a camera bag full of old manual ai and non ai lenses that I use for night time astrophotography. I'd like to buy a D40 and switch from film to digital. My question is, will the D40 match up to my old lenses? If not, is there a way to make them compatible? I'm not at all concerned about the metering as most of the exposures are several minutes long and I will work that out by trial and error. Thanks in advance. I hope I've put this question in the right forum.