I've tried everything I can think of and still find my 500C/M difficult to focus consistently. Using the 45 degree prism and an Acute Matte D screen has improved things, but I still struggle with getting things focused as quickly and accurately as I'd like. I would be interested to hear how focusing a Rolleiflex compares. The only other TLR I've used is an old Minolta Autocord, which I found a bit easier to focus than the Hasselblad, but it has since broken. So pretending everything else is equal, which do you find easier to focus, the Hasselblad 500C/M or the Rolleiflex.