Used 5DM1 vs 50D

I bought my first 5D after I already had my 7D cameras. I never owned a 50D, as I upgraded from 40D to 7D. For portrait and macro, the 5D would be my preference in most circumstances, with flash, that I can envision, of the two cameras under consideration. The 5D even does well in comparison with the 7D, in some ways!

1:1 is the same on full-frame and cropped-frame! A cropped-frame camera does not zoom nor magnify, it CROPS the edges from the image. The apparent zooming occurs when one views the image or print at a given size; that is the viewing/printing device doing the enlarging,

Regarding megapixels, the conventional wisdom is that it takes at least a 4MP increase to see any improvement, and the 50D's MP advantage is less than that.

The 5D perfroms very well at the per-pixel level! DPR shows this well in the reviews. Look at more than just the 5D review; look at the other cameras' reviews, from the same era, in the "Compared To" pages, where the 5D is used for comparison images.

I have not read many of the replies, so it is likely I am repeating what others have already written.