Thanks for that link!

Comparing those pics, especially the 60i vs. 24F pics, it looks like there's enough softening going on in 24F to validate the prevailing theory of "what 24F is" -- it appears that it's basically the same thing as Sony's CineFrame 25. Looks like about 700 lines of res in interlaced, and about 600 lines in 24F. I measured a Sony FX1 (on a different chart) in CF30 at 575 lines, which is close enough to the margin of error (due to framing errors, alignment, etc) that the 600 on the XL H1 and the 575 of the CF30 are probably actually the same thing: one raw (non-filtered) field of video, being de-interlaced to form a full pseudo-progressive frame.

I would guess the only difference between a Z1's CF25 mode, and the XL H1's 24F mode, is the clock speed of the CCD: Sony runs at 50hz, Canon at 48hz. The Digic II processor is most likely interpolating the second field, and then encoding both fields as a "progressive" frame.

Which is probably about the best way to go, actually. Given HDV 1080's penchant for artifacts, CF25 delivers a very nice film simulation on the Sony, and 24F looks great on the Canon, and with the Canon encoding 20% less data per second, plus the somewhat-softened frame detail, it probably helps the HDV codec perform more robustly and resiliently against artifacting. The Canon appears like it actually encodes the frame progressively, and stores it on tape progressively, so it can take advantage of more-efficient progressive encoding. Which also explains why the Sony products can't play back the Canon 24F footage.