Legacy Lens Usage

I just received my V1 and have been experimenting with some of my legacy lenses.  I'm relating my experiences here in hopes that additional tips might be forthcoming from other users.  The first thing I discovered was that the exposure type has to be M in order to use the camera with a legacy lens attached; anything else and an error message occurs indicating that a lens has to be attached.  I was initially quite dismayed because as I changed SS and A (on the lens), the brightness of the image did not seem to change considerably.  Whenever I got the screen to appear reasonably bright, the image recorded would be totally different.  After playing around for awhile I finally gave up and actually cancelled orders for a Canon FD and a Konica AR adapter.  However this morning I discovered something interesting;  if I changed the mode dial to 'movie' then the screen appearance changed accordingly as I altered parameters and most relevant is that the recorded images appeared identical in brightness to what had been displayed on the screen.  The only drawback that I noticed is that under these conditions, only JPEG's can be recorded; no NEF's.

I apologize if the above has already been covered; I did a search and was not able to find much helpful information.  Any additional tips regarding the use of legacy lenses would be much appreciated particularly the possibility of using image magnification.

Brad