I find it interesting in reading this discussion that no one has pointed out that several manufacturers, including Canon and Nikon, but most noteably Pentax, have trumpeted the fact their older FILM designed lenses apparently work quite well with their DSLRs. I had a Pentax ist DS prior to switching back to film and was able to successfully use lenses as old as 35 years old with the proper adapters! Some of their prime Limited series lenses are outstanding, and this on an APS-C size sensor. The only "curse" was the blasted crop factor (1.5x), but it was liveable with for me.
To photograph is to hold one’s breath, when all
faculties converge to capture fleeting reality.