01-24-2016, 01:55 PM
I'm incompetent. I only own Nikon and no more legacy lenses than an old Zeiss 50 mm and a couple of Yashica teles. I've never had the urge to adapt these on Nikon, as the Nikkors and Sigmas I own are simply better and with AF. And I seriously doubt the superiority of legacy lenses in each aspect, especially on a high-res sensor like the 5DRs has. Legacy primes might be as good as a modern L-zoom, but today's Canon L-primes are the lenses that camera was made for. If you're looking for a different look only an old lens can give you - that's another cup of tea and certainly not mine. Sidenote: I first had to look up, what legacy lenses could be... 
I'm not saying the old glass is crap, I'm just saying the last bit of performance is in contemporary lenses. Sorry if I'm not writing what you want to read (at least I suspect so ^_^ ) but I would not use a high-end modern camera and put on that old glass - except there's no new version or the price is so steep I could not afford. The question is what would you gain more than you already have? How about rent a 5DRs and see for yourself? Better to lose some 100$ than to spend 3.5 k$ and learn to live with the feeling "second or third best..."
I'm not saying the old glass is crap, I'm just saying the last bit of performance is in contemporary lenses. Sorry if I'm not writing what you want to read (at least I suspect so ^_^ ) but I would not use a high-end modern camera and put on that old glass - except there's no new version or the price is so steep I could not afford. The question is what would you gain more than you already have? How about rent a 5DRs and see for yourself? Better to lose some 100$ than to spend 3.5 k$ and learn to live with the feeling "second or third best..."