I am making some assumptions - and I do not have un-fettered access to every CCD schematic made by Kodak/Dalsa, I have to search it out (and frankly do not expend a lot of energy in doing so, as my clients are more often interested in the results than the specifications). So no proof, but my supposition is based on my experience with the 3 sensors and my feeling that the results from the 37MP Sensor from the Leica are closer in character to the 50MP KAF50100 than the KAF-40000. Results from the KAF-40000 are more similar to the KAF-31600 (found in P30+/H3D-31/eSprit 65).
Further, the below Kodak PR states the 37500 and 50100 originate from the same CCD platform, but does not mention the 40000. Also, the data sheet from the KAF-50100 stipulates there are no microlenses, which are certainly present on the KAF-40000. I could not locate a data sheet for the KA-37500.
Kodak PR on KAF-37500 & KAF-50100
So you also can't get a KAF-37500 datasheet...interesting. I hoped that Leica might bestow such blessings on one of their bigger dealers.
I've seen that Kodak press release before, but it doesn't back your assertion that the KAF-37500 + KAF-50100 architecture is somehow different from that of the KAF-40000.
First of all, it does say that "The [KAF-37500] sensor also includes specific design features that optimize its use in the S2 camera, such as the use of microlenses
" - thus making it more like the KAF-40000 than the KAF-50100, as I said above. This is one of the few concrete facts we have about the S2 sensor!
Secondly, the only comparison it draws between the KAF-37500 and KAF-50000 is "Both the KAI-50100 and the KAF-37500 Image Sensors are based on the new KODAK TRUESENSE 6.0 micron Full Frame CCD Platform, the company's fourth generation of technology for professional photography. This new platform increases both the resolution and camera performance available for photographers by reducing pixel size and "click-to- capture" time for improved camera response, improving frame rate, lowering power consumption, and improving color fidelity while retaining key performance parameters available from the previous generation of technology.
- But all of that is also true of the KAF-40000.
The press release just doesn't mention the KAF-40000 at all, but that's hardly surprising since none of the new backs/cameras referred to in the release use that sensor.
Absence of a mention doesn't imply a difference.
...based on my experience with the 3 sensors and my feeling that the results from the 37MP Sensor from the Leica are closer in character to the 50MP KAF50100 than the KAF-40000. Results from the KAF-40000 are more similar to the KAF-31600...
Now that's useful information. When you say "results", do you mean colour rendering, high-ISO noise, long exposure noise?