Now I am able to answer my own question :-)
For two months I have been owner of a PhaseOne P45 back and a Cambo Ultima 23 camera with Schneider Apo-Digitar optics. I also bought the Cambo Wide camera with 35mm Apo-Digitar.
Pictures taken with the cambo/Schneider/P45 is MUCH sharper than pictures taken with P45 on my Hasselblad system. So much sharper that from now on I will only use the H-BLAD equipment when I don't have the time to use the cambo.
This back needs top lenses or you will see details missing immediately.
My situation: Commercial Photographer, has been shooting with Hasselblad and Phase One H20 for 2 years. My lenses are from the C-series (Black T*) up to CF-lenses. Excellent quality with the H20 so far. Now I consider upgrading to the P30/P45 digital back, but what about my collection of lenses? I don't like if I have to throw them out and buy the newest lenses (maybe a complete Hasselblad H2 set) to get maximum image quality with the new digital backs.
Does anyone know - how good are the old lenses compared to the newest?? Will they loose in front of a top digital back like P30/P45 ??
Any ideas? Or where can I find more information?