Barry Goyette
Second Officer
Flight distance : 14928 ft
United States
Offline
|
Its interesting, because of my little foray into the land of EI 1600 yesterday, now go4 seems to want to default to that for me, leading several of my shots last night and this morning, to be rated at that setting, and a general freak-out when I looked at the footage today. (entire frame blown out). Nothing to worry about, once all the conversions are set and corrections applied, the footage looks largely the same as the ISO shots of the same subject...but ...well....one thing I notice is that while indeed the info is identical in the file theres sort of an opposite set of problems during grading. Typically I find my ISO 100 shots grade well, but that the shadows can seem compressed and it takes some work to open them up using FCPX's tools. Well the ISO 1600 files had similar difficulties with the highlights...at least given the shots I had to work with. All the detail is there, but digging it out of these compressed looking highlights was just harder. There may be some wisdom rating EI mode at 400 as simply it's placing 18% grey somewhere in the middle. I remember during ProRes EI mode testing that I determined EI 200 seemed to give a more easily gradable file (although for some reason, I still shoot 100). Oh...and, one of the things I noticed on those 1600 clips, is that, as I suspected, at least for what I was doing, the Waveform in go4 was really difficult to gauge.
Interesting also your use of EI mode at 1600. Using Log gammas at higher ISO's to increase sensitivity (push the image) has always been something that you hear people like Alistair Chapman say not to do. Especially in Raw, EI mode gives you identical results at every rating, given the same exposure. So if you're using 1600 in order to get the f-stop you need, then shooting at that fstop, at EI 100, would give you the same result, but also let you know that you're underexposing like hell. Certainly, it's nice to actually see the image on the monitor :-) so there's a reason to shoot at higher speeds, but maybe an intermediate rating would result in images that have better exposure due to the "psychology of the monitor image". FWIW I shoot at end of day all the time with 100, although I don't shoot later than 30 mins past sunset, so I don't know about that situation. Every once in great while I'll crank it up to 400.
As for DJI's curve and the 1600 rating. I'd give that a bit of a grain of salt. Their language there is a little squishy. Essentially they should be saying that 1600 is the maximum EI that gives full dynamic range, and that EI mode is structured so that saturation with 1600 is equal to the maximum code value. As those curves show all of the EI following the same shape and capturing the same DR, it's more about how those curves relate to the waveform than anything. |
|