"Viva la versatility", please criticize this statemeny - 50 mm. (possibly macro) lens

Hi,

I still have a Nikon D50, and I may buy a new Canon body,
not full frame, but DX. One, may think, "the new body has
many more advantages over the older, when getting any
lens with manual focus, get it with a Canon mount".

However, I also think that if I get one lens with a Nikon mount,
I could also use the lens on a Canon EOS camera via an
adpater.

I also wonder if it would be too much too sacrifice not having
the complete exif information when used on a Canon body.

Last, but not least, I wonder, when used with a Canon body,
for example the EOS 72i, (550D) or the EOS 73i, (600D), if
one will need to fully open the aperture in order to meter or
if it will be possible for the lens to meter with a preselected
stepped down aperture ??

Thank you very much in advance, kind regards,

igmolinav : ) !!!