broughtonfilm
Well-known member
This whole dual sensitivity thing is a bit of a sham if you take the time to do some serious testing with proper scopes.
This is actually the main reason why I returned the A7sIII and decided to get FX6. While the dual sensitivity has similar ranges (in A7sIII the low base is set to 640 for Slog3 vs 800 on FX6), at least FX6 has a proper Cine EI implementation allowing greater control. On A7sIII this can sort of be done by staying at base ISOs and simply overexposing / underexposing or by using external monitor with compensating LUTs as MLUTs - a Cine EI for poor. I wouldn't even bother trying to use it that way at all but I find the gap between the two ideal ISO bases too big in practical use, the higher 12800 ISO is very limiting unless you EI offset it to lower values, especially without built in NDs. A7sIII also handles all the intermediate ISO ranges differently than FX6 in Cine EI mode (actually I suspect that it's more like FX6 in Custom mode in that regard), gain is applied to the underlaying signal, it's not just an EI offset. There's definitely some trickery going on under the hood in both cameras, it does not seem to be a true dual gain camera as FX9 I'm afraid. What it really means in practice, can't tell. Can't test FX6 yet as I'm still waiting to receive it... but my hope is that addition of Cine EI and greater (any!) control over noise reduction will be worth it (on top of obvious improvements such as form factor, monitoring tools, internal ND's, audio, etc, etc).
