via provideocoalition: when Allan Tépper asked Panasonic if it was possible to record in ‘native’ 24p or 25p, the answer was no:
Q: When recording in 23.976p (“24p”) mode, does the GH1 always record over 59.94i (“60i”) or is there also a mode to record 23.976p natively, without pulldown? (The native mode has many advantages for professionals.)
A: At FHD mode of NTSC version, it records only in 60i (sensor output is 24fps). It doesn’t offer 24p native recording.
(…)
Q: When recording in 25p mode, does the GH1 always record over 50i or is there a mode to record 25p natively, without pulldown? (The native mode has many advantages for professionals.)
A: At FHD mode of PAL version, it records only in 50i(sensor output is 25fps). It doesn’t offer 25p native recording.
What does this mean: the sensor records in an interlaced mode (one frame all the even lines, the next frame only the uneven lines, etc…) and that date is converted into 24p just before saving. The process of 60i/24p conversion can introduce some artefacts or give cause to loss of resolution.
