Don’t switch base ISO mid shot if using Cine-EI!

Switching base ISO mid recording in Cine-EI is causing some metadata issues in Resolve and perhaps other applications, so I strongly recommend you do not switch the base ISO mid shot.

DaVinci Resolve now reads the metadata from footage shot by the FX6 and FX9 in the Cine-EI mode to automatically add the correct exposure offset. So, shoot at  800 ISO base with the EI set to 200 and Resolve will add a -2 stop offset to the footage so that it looks the same as it did when you shot. Shoot at 800 ISO base and 3200 EI and again the correct +2 stop offset is applied.

However if you shoot at 800 base ISO, perhaps with 800 EI and then half way through the shot change the base ISO to high and 12,800 ISO, perhaps with 12,800 EI Resolve gets a bit confused. It will use the new base ISO but the original EI and as a result from the point where you switch base ISO the footage will look extremely under exposed.

So, if you must change the base ISO, it is better to stop recording, switch base and start recording again.

4 thoughts on “Don’t switch base ISO mid shot if using Cine-EI!”

  1. Alister,

    Apologies that this comment is only somewhat relevant but I’m not sure where to ask it and it is quite poorly documented by Sony: can you explain what is going on with Venice 2’s SDI outputs applying EI to all its SDI outputs? I’m hearing that this cannot be disabled? Coming from FX9, FX6, FS7 etc this is a bit confusing. Is it basically like FX6’S “Quick Cine EI” but only on outputs, not recorded? Thank you!

    1. Yes, if you come from any of the other Sony cameras it is very confusing. According to Sony it is because this is how other manufacturers do it. Which has some truth to it as Arri use a different curve for each EI so the exposure gets normalised. But it makes measuring your exposure tricky as you will be measuring the exposure + offset compared to the internal X-OCN recordings.

      1. Thank you Alister,

        Is such output usable if one wanted to record it? Wouldn’t dynamic range be compromised when there’s EI offset, or is there some kind of magic going on which maintains it despite (I think) gain being applied to the signal?

        How is it implemented in Burano?

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