Two weeks ago, Blog reader "daedbird" first reported that the video recording quality of his K-01 was greatly degraded when the SR was turned on against off. When the SR was activated, obvious rolling shutter effect was seen.
Yesterday, another Blog reader "kadajawi" has responded and writes that it is all about the electronic SR that is actually adopted for all those Prime M Pentax cameras for the Movie mode, K-30 and K-01 inclusive. On the other hand, the K-5 cameras which have the Prime II processor use the hardware SR, i.e., sensor movement, to compensate for the hand shake during video recording.
To verify this, I have checked the online user manuals of the K-30, K-01, K-5 and the K-5II/s as well. It is found that the SR for Movie is defaulted to On for the K-30 and K-01 whilst for the K-5 and K-5II, it is default to be Off instead. So, the supposition of "kadajawi" seems to be true for that "coincidence". Nonetheless, no Pentax manual has ever told anything about the actual SR method and the working principle of it, which yet looks like top secret of their cameras but which we users should actually know about.
Yes, the electronic SR is noiseless but it sacrifices video quality. The mechanical SR is noisy but this problem can be overcome by mounting an external microphone with a shock mount. So, all in all, this is not a real problem and better sound reception quality is gained with the use of an external microphone (and with stereo sound recording possibility too). In practice, my own experience that is the body sensor SR is very useful for handheld video recording to stabilise the video and this feature is still useful when monopod is used.
After all, I think Pentax should give all the Prime M users an option, in the firmware and user menu, for the choice of the SR method via electronic (software) mean or yet the conventional mechanical one, then that would be the best.
Related:-
Definite Guide on External Video Microphone Selection for Supported DSLRs (Brand Regardless)
A Not-so-common K-30/K-5/K-01 Comparison of Mine