In Aperture, select one of the photos with "original missing".
> File
> Locate referenced files
Pop-up screen will show the volume and path that Aperture last found the file.
The "Locate referenced..." selection may not be available if the images were originally imported as " Managed "
I second the comment. I have used a Minolta/Sony f8 500mm Reflex for 3 years on Sony A550 & A580. It is a light weight, auto-focusing, 750mm on the APS-C Alphas. Nice lens to work with on a bright day. Bokeh sometimes needs a little PP. Makes good images even hand held.
Wood Stork in Southwest Florida