S-Log..I should know this, but.....

petermullett

petermullett

Well-known member
Hi guys, I've been away from the F3 for most of this year, and now I've a shoot coming up this week with it so I am trying to play "catch up" with a number of things in setting the camera up properly.
I'll be filming in France, so it will be PAL for this client / project. That's not a problem, got that set. But what I want to do is show the client what S-Log can offer while at the same time offering a regular non-S-Log file. I plan to record the S-Log to my PIX 240, that's fine done that before and love the results....but if I've 2x SxS cards in the F3 how do I ensure that they record non-S-Log files.....or do that just do that anyway?
I know, I should know all this by now, and I could probably work it all out ok by myself but I'd really appreciate advice from those of you that use this camera more than I do and so avoid any stupid set-up mistakes on my part.
Thanks!
 
Turn on Dual link 422 S-Log. Connect SDI-A to the PIX 240, this will record the 10-bit 422 S-log output. Turn on the LUT, right below the dual link menu option, pick your favorite and this will output through the regular SDI / HDMI and record LUT adjusted footage to the SXS. Make sure you are up to date on Firmware, 1.3+ lets you do this.

Anyone want to confirm, don't have my camera with me ATM.
 
Just be aware that you cannot expose properly for S-LOG and non-S-LOG at the same time, so at least one of them is going to be less than perfect.
 
Doug Jensen said:
Just be aware that you cannot expose properly for S-LOG and non-S-LOG at the same time, so at least one of them is going to be less than perfect.
Click to expand...

I'd really like if someone can verify this. In another thread somewhere someone did infact observe different looking footage between ext. in int. recorded footage - however Alister Chapman had indicated that they really should be the same. Obviously with LUT's turned on they would be different, but that would't affect exposure?
 
There is no SLog and Non SLog. Its either no SLog, regular gamma recoding inside and out 420/422. Or SLog external 422 and internal SLog with or without LUT applied.

If your are recording 10 bit 422 SLog from A while recording internally without LUT turned on you will get a 420 35mgbs of SLog footage on SxS. (which will looked under exposed and flat and will need to corrected but is is the same image as A just in 420/35mgbs instead of 422/220 mgbs)
With LUT turned on, you will get 10 bit 422 SLog out of A, and internally you will get a 10 bit 420 with the LUT applied (which is a underexposed image, that is electronically processed to compensate for underexposure and color saturation ) But this is not very accurate exposure compensation and is not to be used as a final image what so ever. It is simply used for a low data rough cut. The camera cannot do two simultaneous image processing at once.

So it's either, SLog in 422 from A recorded to Pix as ProRes 422/220 mgbs with SxS recording SLog in 420 35mgbs or SLog in 422/220 mgbs from A recorded to Pix as ProRes 422/220 mgbs with SxS recording SLog/LUT (with LUT applied in 420 35mgb.)
 
^ yes that was my understanding, perhaps the others thought they were seeing an exposure difference.

Perhaps Doug meant you can not expose for two different curves (ie. Middle grey at different levels on different curves including SLOG curve) - but the F3 can't record that way can it? Ie. Internally using PP (ie. Cinegamma4) and externally SLOG?
 
If your asking can the F3 record internally to sxs in a Cinegammma while simultaneously sending S-Log out to a external recorder?.. No it cant. Would be a a great feature but the internal footage would still be underexposed if you were properly exposing for S-Log.
 
I had started the other thread about SxS vs External recording, but I did use a Hyperdeck Shuttle 2 and edit in FCPX so it's possible there was a gamma shift- however I will post comparisons between SxS and Hyperdeck footage. They look quite different and there was no LUT applied. Unless there's some other menu item I forgot to tick for LUT.
 
I was researching the IRE signal range that Hyperdeck Suttle 2 can record to make sure it will do over 100IRE (unlike prores based recorders) and I read somewhere that you have to change the color levels to RGB levels in dnxhd codec configuration. I suggest you look in the manual for your shuttle and find that option, then perhaps confirm your findings and share them here.

Just to confirm - do you suspect the dnxhd files are off, or the SXS footage?
 
Thanks everyone for the clear and useful advice, really appreciated. Sorry not to have responded earlier but I've been travelling.
I do have one further question though and that's about the LUT that I should apply to the SxS card recording in camera. Which one of those that are offered in the set-up menu would you apply to give as near a "normal" look as possible?
I do have the current firmware and the S-Log version I have is the "paid" one that I had done with Sony in NJ earlier this year.
Thanks again........PM
 
I can't tell you because I don't have the PAID SLOG, but from the documentation there are several 709 REC 800% modes, I have to imagine that one of them will give you a more normal look to SLOG - it really doesn't take much to de-slog SLOG. It can be done using 'levels' in most NLE softwares, or by creating a gentle s-curve with the lows bent downwards, mid-tones locked in original place, and highs bent slightly upwards or left in place.
 
starcentral said:
I can't tell you because I don't have the PAID SLOG, but from the documentation there are several 709 REC 800% modes, I have to imagine that one of them will give you a more normal look to SLOG - it really doesn't take much to de-slog SLOG. It can be done using 'levels' in most NLE softwares, or by creating a gentle s-curve with the lows bent downwards, mid-tones locked in original place, and highs bent slightly upwards or left in place.
Click to expand...


Thanks Starcentral, I'll mess around with the LUTs and see what I feel works better for the client if the SLog output frightens them too much, ( I will not have any "grading" opportunities on this shoot so will have to just hand both media outputs off as soon as we wrap ).
When I've time, and patience, I must figure out how to develop a "favourite" colour correction that I can apply to SLog footage in FCP7......something that will act as a "base" correction.
I think there are plug ins that do this too, but I haven't researched this yet. Do you know of anything that works but doesn't cost an arm and a leg?
Cheers,
PM
 
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