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Gabriel Wilson

Noise WITH F55 slog3.

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Trying to get a low noise image with the f55 but finding lots of noise in the shadows. I posted earlier exposure tips but any thoughts on how to get less noise in the shadows especially during a low light shoot.

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Shoot cine EI.. rate the F55 1 stop lower .. correct in post.. you raise the noise floor 6 db.. any Log gamma won't be good in very low light though.. by the way the data is distributed in the shadows.. or lack there of.. it has a toe in the shadows but no shoulder in the high lights.. your just better off with a hyper gamma curve..7 or 8..if its that dark..you will still have a fair amount to grade with.. log is just not a good choice in the first place..unless you can light it .. not just Sony but Arri or RED too.. nature of the curve..Slog3 is almost exactly the same as LogC..both being a copy of Cineon curve

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So do most people switch to a Hypergamma for low light scenes? Let's say you are shooting a film on the F55 in SLOG3 do you constantly switch to a different gamma for all low light scenes? Would love to hear some thoughts?

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No I don't think a film would have to.. they would have a truck load of lights to deal with it.. light up their talent and let it go dark where they want it to.. or light up the whole place and stop down..I doubt The Crown is worrying about locations scouts that are dark and changing to HG curves.. but for lesser mortals like ourselves .. then I would say that HG7 or 8 is a valid option, to very noisy log footage.. fundamentally a log curve is not great in ,low light as there is just very little data down there.. thats just the science of it.. you can do NR in post but that its a free lunch either.. if you cant raise the light levels ..log will be noisy.. you won't be able to grade at all.. shoot HG7/8 at least you have data and you can grade it.. log isn't always the best choice or needed for every production either for that matter..

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How are you rating the camera? Exposed properly the F55 is exceptionally clean and noise-free. And over-exposed a stop, it's virtually noiseless.

The important thing to test is the native response of the camera. Because with every F55, F5 and FS7 I've shot with to-date, none of them actually matched their claimed sensitivity from the factory, all were approximately a stop slower than claimed.

But exposed correctly to their actual native ISO, they produce incredibly clean images.

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Will be rating at EI800. I'm working with a quite a bit of light on this next project. Robin, you are saying to basically lift the whole location and stop down? how does that affect noise if you are bringing the shadows back down? Where should black fall for a less noisy image?

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If your'e bringing shadows down; it means you got information in them anyway with which to bring down.

It's really much like film; where you'd worry about the shadows of the image and keeping detail there much more so than the highlights; as you have more room. SLOG and LOGC are similar inasmuch as they have a lot of room in the highlights; and not as much in the shadows. As such it's a safer bet to over-expose a bit, and then bring it down later on -v- underexpose and attempt to bring them up. In one case you're computer is throwing away the least important information and in the other you're computer is making up information (out of something substandard).

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It's common practice to rate the F55 at 800 ISO rather than the native 1250. I know some DPs who will rate it as low as 500 ISO for night scenes. I've never had a problem with SLog3 in low light, but a lot of cameras can start to look muddy in low contrast, low level scenes.

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Well I just mean if you have ton of lights and could light up a "dark" scene to be very" bright" and even stop down .. just to make a point that the noise is coming from lack of light hitting the sensor .. which is why people rate the sensor lower as you might film stock.. to purposely "over expose" to correct in post.. 1stop is worth 6bd of noise.. if you have enough lights for your scenes you shouldn't really have any noise problem.. sorry I thought you were saying you had shot and had a problem with noise..

 

But the fact remains that the log curves don't have much data available in the shadows.. Slog3 has a toe down there.. and they are designed specifically for large DR situations.. 14 stops according to Sony..so if you have a shoot in a very dark locations without anyway of lifting the level..your stuck with what you have and you have to shoot as is.. then a HG curve could often be better than shooting Log.. if you have the lights sure not point to change.. but if would probably be a good idea to rate your camera at 800 anyway to raise the noise floor..as seems to be common practice ..

 

It depends on the look you want too . I mean tons of noise is never a good thing.. but sometimes a certain level of noise can be a sort of gritty look you want.. not every night ,low light level shot has to be crystal clear of noise I guess..

I didn't mean to complicate the issue by bringing up HG 7-8 .. on an average drama, with a decent lighting package.. then no.. I doubt any DP is changing from Slog .. but for a low budget shoot.. faced with a scene that they cant light but have to shoot ..thats very dark then it would be a fall back option and would pebbly get better footage than totally noisy .. murky log footage..

 

When Slog3 came out there was alot of rumor that it was noisy in the shadows .. which invariably turned out to be user error.. at the shooting level or post..

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I've read that Alistair Chapman over at XD-Cam User recommends SLog2 rather than SLog3 for low light, low contrast situations, because of the way the curve allocates data to the shadows. I've never tried it, but he's a very knowledgeable person, so it may be worth researching what he said.

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I thought that was just with 8 bit log recording in A7,s etc.. ? but yes tons of good info at his site.. same here only used slog2 till Slog3 came out.. now I only shoot Slog3.cine..

Edited by Robin R Probyn

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I agree with the idea that not everything has to be zero noise, in the same way that people like film grain. It is, at the very least, a matter of opinion. Excessive cleanliness is very unforgiving on anything but the most controlled lighting and production design.

 

That said, I recently had the opportunity, rare for me, to shoot some night exteriors under a reasonable amount of light, to the point where I could run the Ursa Mini at ISO 400, and I'm not sure I ever want to go back.

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Yes one mans noise is another mans Oscar nominated footage.. but at that level I guess its noise/grain that the DP wants..or what suits the film over all more to the point.. rather than their nails digging into the exposure cliff side.. for dear life.. and hoping to get away with it.. :)

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I agree with the idea that not everything has to be zero noise, in the same way that people like film grain. It is, at the very least, a matter of opinion. Excessive cleanliness is very unforgiving on anything but the most controlled lighting and production design.

 

That said, I recently had the opportunity, rare for me, to shoot some night exteriors under a reasonable amount of light, to the point where I could run the Ursa Mini at ISO 400, and I'm not sure I ever want to go back.

I like a little noise in my images, particularly in night scenes. To me it's closer to the way we perceive low light situations. After all, no-one's eyesight is perfect in the dark.

 

I often shoot with stills cameras at 1600ISO, just to get a little texture to the pictures.

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I thought that was just with 8 bit log recording in A7,s etc.. ? but yes tons of good info at his site.. same here only used slog2 till Slog3 came out.. now I only shoot Slog3.cine..

You might be right, although I didn't think that anyone used SLog with 8 bit recording. Recipe for much banding and heartache.

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Yes think it was for the A7,s.. stills camera,s .. that only have 8 bit.. he also advised against shooting LOG 8 bit ..but Slog2 seemed to be better if you were going to..

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Continuing the discussion where do people expose skin tones for slog3 both with and without the rec709 lut for exposure? Does the push change this without the lut?

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I expose skin tones from a calibrated monitor, not from a waveform, and I use a 709 image to do it. It's pretty tricky to accurately judge exposure by viewing Log, as it's so flat. Far easier to do it in 709, and then check highlights and shadows in Log if there are areas you are worried about.

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As above.. personally I would never try to judge exposure .. or focus for that matter off the log image.. use the 709 LUT and expose as you would for 709.. there is also a handy High/Low function in the assign menu.. this will give you highlight and shadow images very handy for seeing how much high light the log image is actually capturing.. which you won't see off the LUTed Image.. no free lunch !.. but I would agree with Stuart.. if you can work off a well set up monitor your away ..

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Out of curiousity. As someone mentioned the crown would love some thoughts on how they might shoot and light the show with the F55 and get such little noise?

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Out of curiousity. As someone mentioned the crown would love some thoughts on how they might shoot and light the show with the F55 and get such little noise?

The F55 is not a particularly noisy camera, but most people rate it at 800 ISO in Cine EI mode, rather than the native 1250 ISO. This helps to reduce what little noise there is, at the expense of 2/3 stop highlight latitude.

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On a recent shoot I found it to be extremely noisy in the blacks even at EI 800. I eventually ended up lifting the black levels above zero but was unable to get the contrast and ratio I wanted. That is why I am so curious how others expose there black levels. ESP such a large production.

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