FS7: New firmware for the FS7 will allow you to bake in gain/offset in Cine EI

starcentral

starcentral

Veteran
Alister posted this a couple hours ago:

"New firmware for the FS7 will allow you to bake in gain/offset in Cine EI. So the log recording can have reduced gain for less noise, but thus will lower the dynamic range."



photo property of Alister Chapman:
jkbyu9.jpg
 
Someone had asked if this was for custom mode but then deleted their post. I'll keep my reply anyway:

No this for cineEI mode.

Before you would use cineEI to rate you camera lower so you would over expose your footage. The later in post you would take your overexposed footage and reduce the exposure so you can benefit form the improved signal-to-noise ratio (lower noise).

I believe what this will do is bake in that offset for you. So the option will do the above step for you, and that way you do not have to reduce exposure in post but you will still benefit from the increase in signal-to-noise ratio.

I hope this comes to PMW series, and the FS5.
 
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Thank you for thoses informations Starcentral!
Is it supposed better than before when we compensate overexposure in post?
Imagine you overexposed but finally even after overexposed you don't need to underexpose in post because image is good like that, you still have more options no?
 
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No this is still overexposing the footage but think of the new feature as applying a -1 or -2 stop exposure compensated LUT to the footage when recorded depending on which ISO you chose.

With the feature enabled you play your footage back and it appears to be exposed as per normal slog3 would ie. middle grey at 41% but in fact you overexposed it but the camera took care of part where you would normally have lowered the exposure in post.

It saves you the step of having to lower the exposure in post. You will lose a bit of dynamic range off the top, but you will get that noise reduction improvement without a lot of effort.
 
I suppose this question is for Alister, but maybe someone else can answer:

On Alister's blog he has two photos of Sigma Cine primes that he owns. In the photos the Sigma Cine primes appear to have a gold / goldish- colored band around them. I've never seen that in any other photos of the Sigmas. Is that just a quirk of the photos on Alister's site? Are the Sigmas in the photos different from the production versions or some one-off that Alister obtained? Or do all the Sigma Cine primes have that gold ring / band?

sigmaFF2.jpg


sigmaFF1.jpg
 
Ok... can someone help me understand this. As is, the FS7 is always recording whatever slog version in CineEI at 2000. And most of us have rated the camera lower - say at 1000 - effectively over-exposing by 1 stop. But I thought this was merely shifting middle gray 1 stop up - keeping the dynamic range of the sensor - but losing 1 stop of highlight latitude in exchange for lower noise in shadows. Which is what I assumed was happening if burning in a 1300% LUT - especially if that offset was built into the LUT.
This new FW option would seem to require a new Sony LUT - with less than 14 stops - if baking in footage...??
 
Liam Hall said:
Also, nice to see the FS7 get some firmware love. Been a while.
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Yeah, every little helps - but frankly, I'm so disappointed with the XAVC-I 300 performance that a fw update only will be of interest to me if it brings the codec's 480 class...I mean really - after getting spoiled by the pristine quality of CDNG/Prores/DNxHR recorded by my Shogun with what the RAW SDI signal provides - I don't use internal recording for nothing more serious than a run&gun scenario...

Piotr
 
Looking at the D Range of the new LUT's is pretty interesting . At EI 1000 Sony is rating the DR of the camera at 650%. Well that's lower than the 800% of HG7 & HG8, even lower at EI 800 which many people use. If that's what's been happening all along have we been kidding ourselves that using Slog gives us more dynamic range than Hypergamma?
 
Hi Lenny,

the percentages are linear values; 1300% equates to 6 stops of headroom, on a scale where 20% is mid grey (an 18% reflectance target) and 100% is reference white (a 90% reflectance target).

'Native' ISO on an FS7 is 2000, so ISO 1000 is one stop lower, or half the percentage so 650% on the charts given. 650% sounds a heck of a lot less than 800%, but in stop terms, it is barely 1/3 of a stop (that's why in custom mode HG7 and HG8 can be set to 1/3 stop lower ISO than the logs can). Logs genuinely do have more dynamic range than HG7 and HG8, just not much! What they do do is spread the love much more evenly across the stops, so give you rather more USABLE range. There is more useful data in both the shadows and the highlights of 10-bit log than in the hypergammas, plus it is very cleanly defined, allowing things like accurate colourspace conversions.

As to the baked-in CineEI feature. The Sony cameras are rated as having 14 stops of dynamic range. In percentage terms this means that as far as the camera is concerned 'Smell The Glove' black is less than 0.08% (that's 8 stops below 20%). In 10-bit recording, S-Log3 sets aside 325 code values for that bottom 20%. The spread gets pretty thin close to 0.08%, but then things are also fundamentally pretty (sensor) noisy there!

In the grade, there may be some interesting stuff to be played with right down into the shadows - particularly if you using a HIGH CineEI - but the reality is that on the whole the bottom stops end up crushed down for thick blacks and to allow increased contrast midtones and highlights. By baking in a LOW CineEI ISO, you acknowledge that you don't feel a great need for that bottom stop or so, with its 5 (!) 10-bit code values going to the next stop up. Everything is shifted down a bit and the brightest white you can reach becomes 10-bit 808 rather than 10-bit 886. You get five stops of headroom instead of six.

If this sounds like a sacrifice, technically it is - you are throwing away about 10% of the top of S-Log3 or S-Log2's data range compared to conventional CineEI (where the low CineEI ISO appears to be a bright exposure), but the payoff is that everything should look like the native ISO, reducing the chance of post cockups. As someone who always hands over rushes at the end of the day for others to then play with, that certainly has an appeal for me, but where I know that post knows what they are doing, I personally would carry on with CineEI as I always have, not baking in but tending to rate CineEI ISO 2/3 to 1 stop below native where possible. If it ain't broke...

A big bonus I can see with this option is that I would expect MLUTs to work as normal, so the baked in exposure shift wouldn't need you to view flat in the viewfinder.

Handy option to have, and I wouldn't mind seeing one more update for the F5/F55 ;-)

Ben
 
This seems useful for dark scenes where one is failing to hit 100 and therefore are not using the full range you can record.

afaik xavc compresses shadows more than mids as the shadows are 'less visually important' - a good concept when designing a 'ready to watch' compressed codec - but a poor strategy for a codec that will be twisted in post

by lifting the ire values that you record shadow areas at the codec will compress them less agressively. so burning the ISO in like this should be a good thing in situations where one did not have enough light to use the full DR of the camera
 
Agree with you Sam - might make sense in certain situations. Would be nice (and maybe possible ??) if an MLut (using Ben's excellent LutCalc) - would allow a user to choose the important "range" - say the highest 10 or 11 stops for a very bright scene or as you say the lower end - to maximize and allocate bits - but this seems a rather odd fw update... wondering what user feedback asked for this.
 
it also makes sense when handing off footage.. no telling the client.. 'it looks bright just dial it back' - obviously a better solution to this would be some adult meta data
 
morgan_moore said:
This seems useful for dark scenes where one is failing to hit 100 and therefore are not using the full range you can record.

afaik xavc compresses shadows more than mids as the shadows are 'less visually important' - a good concept when designing a 'ready to watch' compressed codec - but a poor strategy for a codec that will be twisted in post

by lifting the ire values that you record shadow areas at the codec will compress them less agressively. so burning the ISO in like this should be a good thing in situations where one did not have enough light to use the full DR of the camera
Click to expand...
I would not do this, lifting shadows will compress the contrast in the shadows unless you lift the whole image and ruin the overall exposure.
Compressing the contrast in the shadows will ensure that DCT based compressors will compress the shadows more.

There is no secret, exposing right and tinkering less will give you the best and least problematic images to work with in post.
 
I don’t know if you have ever used a camera in an unlit situation - well shooting Ei there is often not enough light to do the ideal thing - exposing to the right.
That is not a choice - it’s just circumstance - and if circumstance presents like that then using this new option may have value.
 
Cary Knoop said:
You can always get some cheap battery powered LED lights, takes 3 minutes to setup.
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I have expensive lights thanks. I also have a 600f4, a doubler, a camera with a 2x digital crop and military and aeronautical clients. My subject may not be close enough to illuminate with said lights - there are situations where you have to use available light.
 
morgan_moore said:
... there are situations where you have to use available light.
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Yep. Not everyone here is making "movies" or are always in anything resembling a controllable situation. Contrary to some opinions, beliefs and philosophies, No, there is not always time, chance or opportunity to light everything. Outside of interviews and live shots, I'd say 95% or more of what I shoot is 100% available (or unavailable) light.
 
I find its not always about having lights.. but the size of location you have to light.. with 3 small LED lights .. :).. this light every shot is bit bogus on forums like this .. we are not usually totting 18K HMI,s on corp/ doc shoots..
 
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