Hello Franc.
Your question is not an easy one, and I can see why you would ask it.
The problem with the Kodak DCS ProBack Plus is that it was a very good back, and was as they say, before it's time.
The differences between the 16 meg Proback and the 16 meg CFV are: ProBack is 12 bit - CFV is 16 bit; ProBack requires a sync cord from lens to back - CFV does not; ProBack software/firmware is no longer being "upgraded" - CFV benefits every-time the Flex-color software/firmware is upgraded (which is often). Flex-color is the better software. The CFV Images are incrementally better right from the camera and made incrementally better via the software. ISO 400 is better for the CFV than from the ProBack. There is a gain in quality,
but it is not a dramatic, "eye popping" difference.
File format: Both backs produce a proprietary RAW file, the ProBack DCS RAW files can be opened directly in PhotoShop Adobe Camera RAW (assuming that Adobe has retained support of the DCS files in PSCS3), the CFV files cannot be directly opened in Adobe Camera RAW - Flex-color must be used - however Flex-color provides for a quick conversion to Adobe's Universal DNG file format which ACR does support.
The added benefit is that the CFV cosmetically matches the chrome versions of the V cameras.
Given that you can get $3,800. to $4,800. (maybe more) for your ProBack, the cost to move to the CFV at current pricing would be around $4,500. Only you can determine if the incremental improvements are worth it.
RE: The H system and near 645 sensor using a CF Adapter for your Zeiss lenses ... going this route will provide access to a wider field of view, so your 50mm will be closer to a 50mm FOV on the long side of 645 format. I believe the pixel size of the 22 meg back is the same as the 16 meg CFV back, so if you cropped a 22 meg file to a square, the file would be the same as one from the CFV.
Obviously this is the more expensive solution. The CF lens adapter alone is $850 to $1,050.
My opinion:
If you need to sell the Kodak ProBack to finance your next back, then I'd get the CFV now. As the CFV, and Phase One 16 meg backs become more available on the used market, the desirability and price of the Proback will began declining.
I think the CFV will relatively retain it's value even in the face of advancing H technology because it matches the V cameras, is a very good digital back ... and requires no sync cord. Plus it may be the ONLY CFV Hasselblad makes.
One other solution to consider is a stand alone 22 meg back for your 503CW. Were I to do this, I'd also look at Phase One and maybe Leaf.
Your question is not an easy one, and I can see why you would ask it.
The problem with the Kodak DCS ProBack Plus is that it was a very good back, and was as they say, before it's time.
The differences between the 16 meg Proback and the 16 meg CFV are: ProBack is 12 bit - CFV is 16 bit; ProBack requires a sync cord from lens to back - CFV does not; ProBack software/firmware is no longer being "upgraded" - CFV benefits every-time the Flex-color software/firmware is upgraded (which is often). Flex-color is the better software. The CFV Images are incrementally better right from the camera and made incrementally better via the software. ISO 400 is better for the CFV than from the ProBack. There is a gain in quality,
but it is not a dramatic, "eye popping" difference.
File format: Both backs produce a proprietary RAW file, the ProBack DCS RAW files can be opened directly in PhotoShop Adobe Camera RAW (assuming that Adobe has retained support of the DCS files in PSCS3), the CFV files cannot be directly opened in Adobe Camera RAW - Flex-color must be used - however Flex-color provides for a quick conversion to Adobe's Universal DNG file format which ACR does support.
The added benefit is that the CFV cosmetically matches the chrome versions of the V cameras.
Given that you can get $3,800. to $4,800. (maybe more) for your ProBack, the cost to move to the CFV at current pricing would be around $4,500. Only you can determine if the incremental improvements are worth it.
RE: The H system and near 645 sensor using a CF Adapter for your Zeiss lenses ... going this route will provide access to a wider field of view, so your 50mm will be closer to a 50mm FOV on the long side of 645 format. I believe the pixel size of the 22 meg back is the same as the 16 meg CFV back, so if you cropped a 22 meg file to a square, the file would be the same as one from the CFV.
Obviously this is the more expensive solution. The CF lens adapter alone is $850 to $1,050.
My opinion:
If you need to sell the Kodak ProBack to finance your next back, then I'd get the CFV now. As the CFV, and Phase One 16 meg backs become more available on the used market, the desirability and price of the Proback will began declining.
I think the CFV will relatively retain it's value even in the face of advancing H technology because it matches the V cameras, is a very good digital back ... and requires no sync cord. Plus it may be the ONLY CFV Hasselblad makes.
One other solution to consider is a stand alone 22 meg back for your 503CW. Were I to do this, I'd also look at Phase One and maybe Leaf.