Do other people have problems with noise toward the shadows in s-log mode? I was testing today and don't know how comfortable I am with how much I'm getting. I was playing with a few of the popular LUT's in Color and couldnt help but to keep noticing it. It looks like film grain so at least it isn't horrible like what an AF100 has but as much as you read about how clean the F3 is in low light, I find this odd, and these shots were all day or early evening. I underexposed a bit since this is how log looks best. I looked for other posts about this but as we all know, the search function doesnt work that well.
F3: Noise in Slog?
- Thread starter Shoots56
- Start date
Grug
Veteran
It depends on how you expose. Exposed cleanly at 800 ISO, SLOG on the F3 is super clean. Underexposed, you're always going to increase the amount of the noise in the image (but that goes for any camera).
I tend to rate the F3 in SLOG at ISO 1250 and ISO 1600 quite often, for the specific purpose of giving me more range in the highlights, there's definitely noise in the image when you do this, but I don't find it objectionable and I much prefer the look of keeping those highlights under control, it reads as more 'filmic' to my eyes.
When you're not having to balance extreme highlights with deep shadows though (and having to trade off one for the other), I tend to rate the camera at 800 ISO to get a cleaner image.
I tend to rate the F3 in SLOG at ISO 1250 and ISO 1600 quite often, for the specific purpose of giving me more range in the highlights, there's definitely noise in the image when you do this, but I don't find it objectionable and I much prefer the look of keeping those highlights under control, it reads as more 'filmic' to my eyes.
When you're not having to balance extreme highlights with deep shadows though (and having to trade off one for the other), I tend to rate the camera at 800 ISO to get a cleaner image.
lasikdenver
Well-known member
It might also be how you are de-logging the footage. For instance, the Pomfort plugin does some awful things in the shadows. Exposed with an EI between 800-1600 I rarely find any noise of consequence.
Nate Weaver
Veteran
Agreed. Not all de-logging LUTs/curves/methods are built equal.
Since S-Log with a proper LUT is essentially pushed a stop to gain that much in the highlights, if you underexpose by a stop or more, you might have a surprise in post.
Myself, I'd rate the F3 in S-Log at somewhere between 800 and 1600, but not much past 1600 if at all.
This is right on target.
morgan_moore
Major Contributor
im new to the f3 club and performing my first tests. I would agree with the op that slog seems noisy-a trade for retained highlights that seems entirely logical, but not always desirable.
My understanding is that you don't have many options on how to expose.
i am very used to working with raw stills and exposing right for the cleanest possible file.
The nature of the log capture which flattens the highlights means that one must afaik keep skins for example out of the higher values in the exposure zone.
My initial testing backs this up and I am getting a best result with a grey card put at 38 which is afaik what the "manual" suggests?
It seems therefore that you don't really have any choice in "how you expose" (unlike in raw where you can ettr if you can accept the highlight trade offs that implies)
I am wondering if one can make the camera cleaner by using a more linear profile in lighting situations where you don't need the amount of dr offered by slog. To me that theoretically makes sense.
Maybe those with more time with the cam would share further thoughts ..
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One question for you. Generally in SLOG I go with:
Lo: 0 db
Mid: +3 db
Hi: +6 db
However, if I wanted a truly clean 800 ISO, should I go with the following? :
Lo: 0 db
Mid: 0 db
Hi: 0 db
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morgan_moore
Major Contributor
Lo mid high - what settings are you referring to?
ISO is adjustable in all three areas of an image low, med, high. Not just globally.
Abelcine's ISO ratings for the F3 natively:
-3 db. = 500 ISO
0 db = 800 ISO
+3 db = 1000 ISO
+6 db = 1600 ISO
+9 db = 2000 ISO
+12 db = 3200 ISO
+18 db = 6400 ISO
Factory settings are: 0, 6, 12
See page 48 of the manual:
http://ws.sel.sony.com/PIPWebServices/RetrievePublicAsset/StepID/SEL-asset-250124/original/PMW-F3 Ops Manual.pdf
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Nate Weaver
Veteran
What you have to understand is that log exists for one main reason...it is the best encoding for putting the most information in the 10bit container the codec puts it in. Regardless of what subject matter hits what brightness.
ACES flow/colorspace, for example, takes the S-Log encoded gamma, and flattens it out into linear (yes, just like raw) as a first step. It's true that the higher brightnesses have somewhat less bits to describe the levels, but not enough to really ruin them unless the skin tone highlights hit maybe 90IRE. ACES flow then puts a NEW gamma curve onto the image to roll off the highlights and shadows to a pleasing final image. In Resolve, using the gain wheel in ACES is an awful lot like using the ISO or Exposure slider with raw material; i.e. there is little downside to "re-exposing" the image using gain. It looks natural.
The best 3D LUTs will give the same end result, but all the math is rolled into one step, unlike ACES where it's multiple internal software steps. Not all S-Log LUTs behave like this.
In my experience, you have about a stop's worth of choice. 1600 or 800. You can get away with between 800 or 400 if you're shooting flat daylight exteriors or studio interiors where you can control your highlights/lighting ratio.
morgan_moore
Major Contributor
Nate - fantastic post. How can I get that linear start point in resolve 10?
morgan_moore
Major Contributor
uou confused me by suggesting leaving all if the settings at 0? Which would not give you any option to change "iso" .. Unless you are changing it somewhere else maybe EI menu?
Nate Weaver
Veteran
Turn on ACES in Master Settings. And then go into look up tables panel and turn on Rec709 as Output Display Transform.
Here's the problem though. There's no Input Display Transform for the original Slog. Only Slog2.
You also have to make sure Resolve is reading your media files as 0-1023, not 64-960. If you don't, Resolve will not use blacks below 64 or highlights above 960, and everyhting will be too crunchy.
As it is, using the IDT for SLog2, things will be a little contrasty and saturated. But try lowering Contrast in the 3-way gain panel, and bump saturation down.
Dennis has done a good tutorial video about using Sony footage in Resolve, I think it's on Vimeo.
But my point for my previous post was a comment on you preferring linear overall. You can get there from SLog. There are not equal bits distributed throughout the dynamic range, but you can get to linear and it works well...CGI people have been converting 10bit LOG Cineon files to linear for many years for compositing and FX work (compositing works much better in linear space, google Stu Maschwitz)
ACES, in my opinion, works magic with SLog2 files specifically because it breaks the processing up into discreet steps. Convert to linear (IDT) --> Change exposure/balance/"grade" --> Apply nice film curve (aka, the RRT) and finishing target gamma (ODT) for output.
Here's the problem though. There's no Input Display Transform for the original Slog. Only Slog2.
You also have to make sure Resolve is reading your media files as 0-1023, not 64-960. If you don't, Resolve will not use blacks below 64 or highlights above 960, and everyhting will be too crunchy.
As it is, using the IDT for SLog2, things will be a little contrasty and saturated. But try lowering Contrast in the 3-way gain panel, and bump saturation down.
Dennis has done a good tutorial video about using Sony footage in Resolve, I think it's on Vimeo.
But my point for my previous post was a comment on you preferring linear overall. You can get there from SLog. There are not equal bits distributed throughout the dynamic range, but you can get to linear and it works well...CGI people have been converting 10bit LOG Cineon files to linear for many years for compositing and FX work (compositing works much better in linear space, google Stu Maschwitz)
ACES, in my opinion, works magic with SLog2 files specifically because it breaks the processing up into discreet steps. Convert to linear (IDT) --> Change exposure/balance/"grade" --> Apply nice film curve (aka, the RRT) and finishing target gamma (ODT) for output.
morgan_moore
Major Contributor
Nate. Fantastic - ill mug up on all of that. I'm very used to a too crunchy start point as that is kind of the stills norm..
and yes I sort if " get" how slog is using the "space" - just that is a jump for me coming from cameras with knee that certainly over compress the highlight info..
and yes I sort if " get" how slog is using the "space" - just that is a jump for me coming from cameras with knee that certainly over compress the highlight info..
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Today I was using a LUT that Andy made at Abelcine. I tried a few others as well but there was little difference in the ones I tried.
The advice is nice but not all of us can use Resolve and the discussions always seem to revolve around it. I use Color because my 8-core MacPro will not run Resolve because, apparently, it is not a 64bit system. I tried everything but it wont work on it so I'm stuck with the so called outdated stuff.
I will do some more tests tomorrow but what I am finding for doing outdoor day shots is if I try to keep skin around the 30-40 mark and watch highlights with zebras set at 100 it works out well. I assume this must be a decent guide from seeing the results but nailing a sweet spot and being able to understand how to hit it on the run seems almost impossible. Having a rough guide to keep in mind is where Im trying to get to. I feel like I need a formal class to reset my brain. Exposing film is easier than this!
The advice is nice but not all of us can use Resolve and the discussions always seem to revolve around it. I use Color because my 8-core MacPro will not run Resolve because, apparently, it is not a 64bit system. I tried everything but it wont work on it so I'm stuck with the so called outdated stuff.
I will do some more tests tomorrow but what I am finding for doing outdoor day shots is if I try to keep skin around the 30-40 mark and watch highlights with zebras set at 100 it works out well. I assume this must be a decent guide from seeing the results but nailing a sweet spot and being able to understand how to hit it on the run seems almost impossible. Having a rough guide to keep in mind is where Im trying to get to. I feel like I need a formal class to reset my brain. Exposing film is easier than this!
bill totolo
Veteran
Are you using an approved video card?
Grug
Veteran
You always have options with exposure, exposure is a choice. If I want a bright light source to overexpose a persons face, then I'll overexpose their face (the important thing is simply working within the realm of what looks good with the camera - i.e. you don't want to go so bright that you get clipping and then lose detail in the person's face).
In SLOG, the F3 has beautiful, soft highlight rolloff (it's substantially smoother than the Red MX which is the primary reason why I chose the F3 over a Scarlet - which is otherwise a wonderful camera). So if you want hot images, you can have them, and they won't look too video-ish - you just have to work within the camera's limits. However so far as setting your base exposure, with log encoding you do want to put 'white' and 'grey' pretty close to their specified IRE values of 38 and 68 for the best results.
If that sounds confusing, it's because your base exposure is a separate thing from how you choose to expose different elements within your frame. Which is to say that you set your base exposure, and then choose whether you want a person or element in the frame 1-stop or 2-stops over or under-exposed relative to that base exposure.
For example, if I have a 'big finale' shot and a door is going to open and brilliant white is going to flood into the room and envelop my character, I would set my base exposure for 800 ISO (i.e. get that grey card to 38 IRE) and then set the light flooding into the room at a level that will boost my actor's skin up to somewhere around 68 IRE - so that when they get lit up, their skin tones will brighten up to the same level as 'white'. This means that when the footage is de-logged I'd have a perfect exposure on their face before the bright light enters the frame, and still retain the skin detail once the overexposed kicks in.
With log encoding especially, I've found it really helpful to simply think of exposure in terms of IRE values. For all intents and purposes you've got a scale of 1-100 IRE. So you just have to set your base exposure so that different elements within the frame hit the level of brightness you want them to. If you're rating the camera at it's native 800 ISO, that means middle grey should sit around 38 IRE, and white should sit around 68 IRE. Relative to those two baseline points, anything that's going to essentially be black in your frame should sit between about 1-22 IRE, caucasian skin tones should sit around 42-45 IRE, highlights on caucasian skin tones should sit around 50-55 IRE.
If you start thinking like that (giving elements within the frame relative levels of brightness based on IRE) you can begin to very quickly and easily set your exposure using false colour or waveform monitoring.
With every stop of increased gain (6db) to the sensor you lose about a stop of dynamic range off the highlights. So unless you're shooting at nighttime, in serious darkness, and need the added shadow detail in the background, I'd advise against increasing the gain for most things. The camera is natively 800 ISO in SLOG, so just leave it at that (0db) and rate the camera a stop or half a stop faster at 1250-1600 ISO and push it in post.
For the cleanest possible images, set the camera at 0db (which is 800 ISO) and rate it at 800 ISO. So long as you don't have blown highlights to worry about, that'll give you the cleanest, least noisy images possible.
There is no input transform to take SLOG from the F3 into ACES. It's a real pain (especially since everyone seems to have given up on providing any further development or support for the F3 (a camera that's only just shy of 3 years old for goodness sake!). Without a properly calibrated input transform, you're not going to really get the benefits of ACES (as far as I can tell from my readings on it), so I'd suggest just sticking to YRGB in Resolve.
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morgan_moore
Major Contributor
A knowledge of film is a great start point. But with film you make a two choices for every can.
What stock?
Will it be pulled or pushed in the soup?.
Those are nailed choices. And you expose for those choices. "Easy".
With digital you get an onboard lab, so can choose to push or pull or choose a different stock for every shot.
You have two choices make that learning leap.
a) picking a profile and locking your look and then learning it (treat it like film).
b) To make the learning leap to using (and communicating to other parties, using flimsy non standardised procedures) the onboard lab.
As for Resolve - well you might just need a new computer to get the most from your camera. Computers are cheap.
morgan_moore
Major Contributor
I will define 'choice' - maybe I should have said 'costless choice of exposure'.
With a 'perfect' linear 16bit raw camera and a scene of smaller DR than the capability of the sensor one can expose at different levels and in post the two files can be made to exactly match - a 'costless choice of exposure'
The only difference is that debatably the ETTR 'choice' is cleaner.
With a camera with a gamma curve, and a smaller 8 or 10bit space , if you put certain values at certain points on the curve then not enough data is recorded to manipulate the file to a different place - well known that if you put skins in the knee of (709setup) sony camera the skin-tone is lost (plastic) due to recording at a point where the gamma curve is too flat and not enough tonal valuations are recorded to create a pleasant skin tone.
This is an 'exposure choice with cost'.
Nate is teaching here that SLog/Aces/Luts can get one to a situation where one is close to a 'costless choice of exposure'
Understanding this will (I dont fully yet) enable one to ETTR and therefore avoid noise in Slog which is the subject of the thread.
S
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