@paul, david,
thank you very much for letting me know about the accurate test for dynamic range. as i mentioned before this firmware is still the beta test version, i found couple of minor bug and error...i bet they will fix these by the time we get the final version so i rather have a fun time...
today i just had borrowed "firmware upgraded FS700" from Sony Japan for little test.
it's still beta/test based firmware but the S-Log2 is active already so i'll test with the internal AVCHD and the external ProRes recording.
let's see how it goes and i will post the review and sample...