View Full Version : FS5 S-log tips and gotchas


Nigel Davey
May 26th, 2016, 03:32 AM
Thus far I've only used profile 1 (cine) on the FS5 and Doug Jensen's Vortex-FS5-Pro cine profile. I have never used log before on the FS5 or any other camera.

This weekend I intend to go out and shoot some test footage in S-log to a) get some experience and b) work out a good workflow. I would really appreciate tips, advice and a heads up on the gotchas before I attempt this. Keep in mind I'm starting from scratch, so need to start/learn from the basics upwards.

I suspect the two areas I need to really get my head around are achieving correct exposure and monitoring on camera. So advice about ISO's (I tend to use dB right now in cine), zebras (with recommended levels), S-log 2 or 3, etc, are gratefully received.

I know Alister Chapman covered a lot of this in his FS5 introduction video last year. So I will go and watch that. But nonetheless folks have had 6+ months of real world experience since then, so I'm interested in your thoughts.

In case it's relevant, I intend to go and shoot test footage at a old ruined church that was bombed in WWII. So there will be a fair amount of of grey stonework, green ivy, broken windows/frames, headstones and (hopefully) blue skies. In terms of lens options I have the Sony 18-105 kit lens, a Sony 35mm (f1.8), a Tokina 11-16mm (f2.8) and various Nikon glass (70-200, 18-55, 35, 55). I'll also take my slider, jib and sticks for support/moves.

I suspect my three main lens choices on the day, unless advised otherwise, will be the Sony 35, 18-105 and the Tokina 11-16.

Dave Sperling
May 26th, 2016, 09:22 AM
My advice would be to do some simple s-log testing in your own office or living room before going out in the field. Put up a gray scale and color chart - have someone stand in - shoot at a variety of exposures - see what your parameters are when you start grading. My feeling is that s-log exposure will be somewhat personal based on your subjects and workflow, so try out a variety.
Also remember that when you are shooting a 'test' the idea is less about getting usable footage, and more about finding our what your optimum settings are. So unless you have time for numerous different/documentable options for each setup, don't try to do a test with something you are worried about capturing.

That said, occasionally a 'test' ends up being surprisingly usable. Not the same camera, but the idea here is informative. I was recently doing a shoot of scenes from a Broadway show. (They were doing the scenes specifically for us during the afternoon - creating press clips - and the lighting designer was there to adjust the lighting design for better video images.) We were using regular disc-based cameras for the shoot, but also had an A7s for some specialty shots. I'd adjusted a profile to closely match the big cameras, but we decided to shoot some test s-log footage (unmanned wide shots, since we were all operating on the big cameras at the time.) There were a lot of video projections on scrims as part of the set, and the big cameras were having trouble seeing them. We tried several different s-log exposures just to have some footage (not actually intended to be used) that the company could play with grading to learn more. Interestingly enough we found that what was theoretically a good couple of stops overexposed (faces recorded up around 80%) ended up giving them an image that worked beautifully for bringing up video projection details in the shadows with minimal noise -- while the compressed curve area of the overexposed faces was not that bad in the extreme wide shots. They were able to use some of it in the finished cut - because the important part was seeing the dim videos, and the s-log kept the faces gradable / with detail. Would I recommend exposing faces at 80% -- ? Absolutely not / Never. But our test bracketing found a loophole. also note that in grading they had to make their own custom curves rather than use a LUT, since the LUT would have probably placed the brightness on the faces somewhere in the light bulb range...
One thing to think about with s-log is where you need to expose, based on how you color correct the footage, to keep your shadows from being too noisy. You will only determine this with testing.

Nigel Davey
May 27th, 2016, 03:51 AM
Thanks Dave. Some great advice that I will be following as I conduct my tests.

Cliff Totten
May 27th, 2016, 02:50 PM
Important - SLOG-2 and SLOG-3 do not top out at the same IRE on your scopes/zebras.

Going from memory here but SLOG-2 will clip right at around 109-ish like some other profiles do. However, SLOG-3 clips way lower. I want to say it's 94 IRE? So check that and make sure that if you want your zebras to reveal what is clipping in your shot, you will need to lower them down. 94 IRE is roughly the brightest possible white.

The Fs5 seems to be OK these days, but older Sony SLOG camera's like the original A7s will often clip bight blue lights in the most bizarre way. Things like stage lights or police car light and more would have a nasty blue channel saturated halo around them. Again, I think Sony has fixed this on newer models like the RX10-II, A7s-II and FS5.

CT

Nigel Davey
May 27th, 2016, 04:38 PM
Thanks Cliff. I think I'll mostly be using Slog 2, so will set zebras to 109.

Cliff Totten
May 27th, 2016, 07:28 PM
Make sure to point to point at something like a bright light and deliberately blow it out pretty bad. Then, make sure your zebras are right at that clipping point. Also, you might be able to trust that the 109 IRE internal is exactly the same 109 IRE output over HDMI but you might want to verify that to make sure. I have not tested that myself with my FS5 yet but I'm guessing it should be exactly the same.

Doug Jensen
May 28th, 2016, 04:29 AM
Thanks Cliff. I think I'll mostly be using Slog 2, so will set zebras to 109.

109??? !!
I hope you realize that you'll be over-exposing by several stops above Sony's recommendation of 61% for whites. Even if you weren't shooting S-LOG, I can't really imagine any scenario where 109% zebras would be a good idea. Zebras should be used to help you get the correct exposure -- and not just to tell when things have gone over the cliff and are about to clip. That is not what zebras are for.

Personally, I think Sony's suggestion of 61% is too low, but I don't know anyone (who's work I respect) who would go over 75% on bright reflected whites. 109% is way over the top. S-LOG is NOT designed to have highlights pushed right up to the brink of clipping. I highly suggest that you follow Dave's advice and shoot some controlled real-world test footage with S-LOG and then bring it into DaVinci Resolve and go through the entire workflow -- all the way to delivery in order to ensure you've got a handle on it before you embark on an important shoot. S-LOG is not a workflow you should take lightly (pun) and requires a different way of shooting and post processing.

Also, you don't say in your post above whether you'll be shooting UHD or HD. If you're planning on doing UHD, I suggest you abandon all plans for S-LOG with your FS5 because the files will only be 8-bit . . . and 8-bit isn't good enough for quality grading of S-LOG. You'd be much better off baking in a WYSIWYG look with one of the other gamma choices and then only doing minor touch ups in post.

Nigel Davey
May 28th, 2016, 06:08 AM
Thanks Doug re advice over zebras. I will only being doing tests in HD. Being perfectly honest the type of work I get is most suited to cine profiles for now. But nonetheless I want to find out what those extra stops of dynamic range can offer in a pinch.

Unfortunately I don't have Resolve. For PP I was intending to start with the S-log LUTs offered under Lumetri in Premiere and then go from there.

On a connected but different note I assume the better workflow with the FS5 is to use the Gamma Assist Display? ... although using zebras for setting exposure.

Also is there any value in using AE adjustment to achieve the recommended over exposure. Or is that already baked into the FS5 PP7?

Keep in mind I'm just starting out with log and have set aside the rest of today to read articles/watch tutorials.

Cliff Totten
May 28th, 2016, 09:48 AM
Doug is absolutely right. SLOG requires ALLOT of practice. Actually, TWO types of practice:

1.) Shooting with it. Exposing SLOG is nothing like most of us are used to with "rec 707 ish" profiles. You will need to learn the term "expose to the right". So, you will over expose between a stop or two and then bring "down" your wave form in post. SLOG is only an archival technique designed for maximum dynamic range capture in a small rec 709 "bucket". It looks terrible but that's OK, it's only job is to "get it all in". You job is post is to expand it all back and reallocate the brightness where it "really" belongs. (in a very careful was of course)

2.) Grading it. This takes allot of practice too. If you over expose between 1-2 stops without clipping the important areas of your scenes, you bring your waveform "downward" in post and this will help to hide noise. You NEVER want to be in a situation in post where you need to bring levels "up" or adding gain. It's noise city! Bringing "down" is good, bringing "up" is bad. The idea is to capture a brighter image in the field that is not clipped, get home in post, adjust your whites and normalize in the "downward" direction.

Yup, normalizing SLOG-2 on an 8bit capture is very tough on those 8 bits. With only 255 steps per RGB channel, they do not that stretch well! However, if you expose very carefully in the field, you can get decent results. SLOG-3? It's soooo nice but you really need 10 bits for this.

Please do not shoot SLOG on a job if you have never done it! Do lots of testing first.

The best resource I know on SLOG exposure (and proper over exposure) is Alister Chapman. He is a well respected guy that speaks for Sony in many events.

www.XDCAM-User.com

http://www.xdcam-user.com/2015/12/deeper-understanding-of-log-gamma-experiments-with-a-waveform-display/

http://www.xdcam-user.com/2014/08/exposing-and-using-slog2-on-the-sony-a7s-part-one-gamma-and-exposure/


Also, on the FS5 with SLOG-2, only shoot at 0db/3200ISO. Dont add gain to you shot. If you need more brightness, add more light by opening your IRIS or slowing your shutter. (remember, gain/ISO is not "light") If you still cant get the brightness you need, turn off SLOG for that shot.

Cliff Totten
May 28th, 2016, 10:34 AM
109??? !!
I hope you realize that you'll be over-exposing by several stops above Sony's recommendation of 61% for whites. Even if you weren't shooting S-LOG, I can't really imagine any scenario where 109% zebras would be a good idea. Zebras should be used to help you get the correct exposure -- and not just to tell when things have gone over the cliff and are about to clip. That is not what zebras are for.

Personally, I think Sony's suggestion of 61% is too low, but I don't know anyone (who's work I respect) who would go over 75% on bright reflected whites. 109% is way over the top. S-LOG is NOT designed to have highlights pushed right up to the brink of clipping. I highly suggest that you follow Dave's advice and shoot some controlled real-world test footage with S-LOG and then bring it into DaVinci Resolve and go through the entire workflow -- all the way to delivery in order to ensure you've got a handle on it before you embark on an important shoot. S-LOG is not a workflow you should take lightly (pun) and requires a different way of shooting and post processing.

Also, you don't say in your post above whether you'll be shooting UHD or HD. If you're planning on doing UHD, I suggest you abandon all plans for S-LOG with your FS5 because the files will only be 8-bit . . . and 8-bit isn't good enough for quality grading of S-LOG. You'd be much better off baking in a WYSIWYG look with one of the other gamma choices and then only doing minor touch ups in post.

109 would be the actual clipping point that would make something unrecoverable in post. If you caught some highlights (like bright clouds) at 105 you could draw those back in range and normalize them in post. Once they break the 109 barrier, they are permanently destroyed. That's all I'm trying to say about using Zebras for that function.

Also, how we expose something is very scene or "subject" dependent. If there is black bear fighting a grey wolf under a shady tree, we worry less about burning our clouds or even the grass in the distant field. We gotta get that bear in the shadows over anything first. So we often "choose" what parts of our image to destroy and what parts to save. Even SLOG can't give us everything.

I think Alister's +1-2 stops over is a good rule of thumb and works very well for most scenes. He has some nice LUTS too that are specifically tailored for +1, +2 and +3 over exposure.(+3 is allot)

If you are stuck in a really high dynamic range scene with SLOG2 and you have everything that is important you from 109 and below, you have allot information to work with in post. (easily 13+ stops?) 109 is super hot and highlights can look squeezed up there.

How much post work do you want to do? People have to figure that out when they are shooting it. Everybody is different.

CT

Nigel Davey
May 28th, 2016, 12:29 PM
Thanks Cliff. This afternoon I've watched both Doug Jensen's FS5 Master class on picture profiles and the hour long section (relating to cinegammas and slog) Alister Chapman gave on the FS5.

A couple of things stood out that I now how questions on. Doug prefers to use slog 2 in HD whereas Alister recommends slog 3 because it apparently grades better and doesn't generate a green tint when strectching levels.

Tomorrow I intend to shoot/test on a dessertedand ruined church (think English church with grey flint stone) and the weather forecast is good. Thus lots of light and possibly even clear blue skies. Since I intend (for now) to grade in Premiere CC by applying the relevant LUT and therefater tweaking by eye, most likely with Lumetri, can anyone advice whether slog 2 or 3 is the better option.

For exposure I think I'll try Alister's recommendation of setting zebras to 70 (for either slog 2/3) and popping a piece of white paper in front of the camera and tweaking exposure until the zebras appear. That should put the exposure over by 1-1.5 stops according to Alister. So I assume that will give me a starting point for peak white. I assume after that I'll need to get a feel for how things look on the screen with the Gamma Diplay Assist enabled and tweak exposure as it feels appropriate.

A couple of things I'd like some clarification on though. Firstly I assume the requirement to overexpose by 1-1.5 stops is not built into pp7, pp8 or pp9? In other words is it ok to let things look a stop or so overexposed on the monitor (with gamma assist enabled)?

Secondly how do I get zebras to precisely 70? My current understanding is they have a aperature setting (for bracketing) that the lowest you can set it to is 2, thus 1 either side of 70 in this case. Will that make any tangible difference?

Finally if I do go with slog 3, which version is potentially better for my church scenario pp8 or pp9?

Forgive me if these are daft questions, I've taken in quite a lot today and perhaps not fully grasped it all.

Also I genuinely appreciate the time folks are taking to try and steer me in the right direction.

Cliff Totten
May 28th, 2016, 01:19 PM
You are not asking daft questions at all. They are excellent questions.

SLOG-3 is spectacular. It really is wonderful and it doesn't "curve" the way 2 does. 3 works in a way that more linear than 2. It sees deep into the shadows but it is brutal on an 8 bit codec. That 100mbp/s XAVC long GOP codec is a good one but SLOG 3 hammers it hard. I have gotten "OK" results with SLOG3 and 4:2:2 ProRes via HDMI but there is no escaping the 8 bit limitation and the color banding that it brings.

When I shoot SLOG, I mostly record to ProRes on my Shogon or Pix E5. ProRes is an intraframe CODEC that is pretty durable as far as compression artifacts go. Stretching your waveform in post will bring out compression artifacts too. XAVC-L is OK but ProRes holds noticeably better with SLOG to my eyes. (wont really help 8bit banding much)

I tend to use multiple Zebras. I have SLOG clipping point on the small camcorder screen and 70- 80 on my bigger monitor. Depends on what I'm shooting.

I do love Alister's +1 and +2 over exposed LUTS. I do have his +3 installed too. I donated on PayPal for them. They are well worth it. I tend to bounce back and forth radically between LUT and no LUT on my external monitors but almost never use Sony's camcorder monitor assist. Once you see that milky SLOG look, you start to get used to it!

When you shoot SLOG, you almost have to say in you mind "Hmmm...exactly how will I grade this exact thing here..." and do that will EVERY shot. The closer you get it right in the field, the less stress you will have in post.

Because SLOG-2 is easier on 8 bit, I stick mostly with that. It's a bit more tricky to grade than SLOG 3 but it's not as flat as 3 and uses almost all of the bits that 8 bit has to offer. When you see SLOG-3 on you waveform monitor, your darkest black is WAY up and your brightest white is WAY down. You gotta stretch is like silly putty to normalize it. It really needs 10 bit. (1024 steps per RGB channel...instead of 255)

SLOG took me literally a year of practice. I strongly recommend getting allot of test shots that are deliberately "BAD". Try shooting SLOG-2/3 on automatic and +/-0EV. Just let the camera decide your exposure. Lift up that video in post and see all that noise? Then shoot the same scenes +1 and +2 over. Bring it all down and see how different the grading result is? Deliberately UNDERexpose by -1 or -2 stops and see how bad the problems show up in your NLE. Scarry!

Shooting bad SLOG video and trying to grade it really is one of the best ways to understand SLOG and getting it right.

Nigel Davey
May 28th, 2016, 01:39 PM
Thanks Cliff. I'll try a variety of combinations tomorrow. Might even shoot standard Rec709 or Doug Jensen's profile on the same scenes to see what I gain and lose in Post vs slog.

Out of interest now that you've mastered slog, roughly what percentage of your footage/projects do you use it in?

Cliff Totten
May 28th, 2016, 02:04 PM
lol,...dunno if ANYbody can say they are an SLOG "master"...hehe. I'm just a regular guy that shot allot of bad video, READ ALLOT, shot even more and eventually figured out over time how to get consistently good SLOG video with. It taught me how to color grade much better as well. That's all. I'm nobody special!

I use it only for projects that I know I want to spend allot of time on. I'm going to Yellowstone in August. I'm taking my FS5 and a A7s-II rig. I'll probably shoot 90% in SLOG-2 on a PIX-E5 external recorder. 100% 8 bit UHD. (On the FS5, I'm choosing resolution over bit depth)

This is because I'm expecting to take allot time of carrying gear, carefully shooting and grading. For "normal" projects, I dont use SLOG. I do what Doug does. Get it close in camera, do light tweaks in post and get it out the door.

Here is the ironic thing about SLOG. You can capture all this dynamic range but at this moment, you really cant "deliver" that dynamic range! What are you going to do? You will capture more highlights and potentially more shadow detail but once you add all the contrast back in, shift the waveform down and normalize it to look good for typical rec709 televisions/monitors....you just tossed out all that extra range that you worked so hard to capture! Right?

This is what SLOG is, a "capture" and "archive" format. It's not a "delivery" format. What you CAN do is return to a project years from now, when rec2020 TV's are more popular and re-render a new file that DOES deliver all that range you captured.

SLOG just gives you some more options in post that you might not get with rec709. More information captured in your image that you can decide what to throw away or to keep later on down the road.

CT

Nigel Davey
May 28th, 2016, 03:24 PM
It's interesting you say that Cliff. It ties in with something I've noticed in quite a few log clips I've watched online. Either they still look a bit milky or they look like you would get similar results from 709.

I'll still play with slog to see what is achievable in post. But now you've said what you have, I will definitely record a duplicate clip in 709 to compare it with.

On the plus side most of this years new 4K TV's seem to have HDR. Not sure if there is a universal standard yet though.

Nigel Davey
May 30th, 2016, 08:44 AM
I just found this video which details all the Cinegammas and S-log profiles: https://youtu.be/0Z7hV4Tho_o

It's a shame this wasn't out when the FS5 was first launched. It would have helped a lot of folks given how little info was released re factory preset FS5 profiles. But on the whole this video fills in the gaps.

That said it is frustrating Alister recommends shooting 1-1.5 stops above the FS5's S-log exposure baseline. I assume he's correct. But if so it makes Sony's baseline irrelevant. Worse still, a complete hindrance since the Gamma Display Assist is inevitably wrong and must be made to look overexposed to get a desirable slog exposure. Which begs the question, what is the point of it?

Is this a case of Sony needing to come clean and admit their slog exposure basline is wrong and subsequently adjust the Gamma assist in a firmware update.

Cliff Totten
May 30th, 2016, 06:25 PM
That is why I said up in an earlier post that I dont use the built-in Sony assist function. I load Alister's SLOG-2/3 +1, +2 and +3 LUTs in my Shogun and Pix E5.

Try this as a very simple and quick test. Toss in SLOG-2, go outside and shoot one scene in full auto using +/- 0 EV. Let the FS5 pick what it thinks the exposure should be. Then do the same shot again but run the auto at +1.0 stop brighter. Do the shot again with a +1.5 EV auto over exposure. (for this auto test, don't worry about how bad your monitor looks or where your zebras are for this as only the camera is doing the judging)

What happens when you load those files up on your NLE? Without knowing anything about the scene type, I'm guessing that when you add contrast back, you are forced to lift the 0EV in post. If you lift it 3 or 6db , the noise can come right up with it. What about the +1 and +1.5? I'm guessing there is a better chance that the contrast center is closer to where it needs to be and will not require much, if any lifting. If anything, you have a good chance of being able to bring it DOWN -3db or more. The more the better because doing this hides the noise floor and helps your image look cleaner.

Alister's +1-2 stop over rule works VERY well. You can trust it!. You can sort of think of it this way,...Slog "compresses" brightness. This allows you to "pack" more brightens into the recording and pull the levels down to where they "really" belong in post. (expanding contrast in a more downward direction)

This all sounds complicated at first but just try the 0EV and the +1EV and +1.5EV scenes and watch the affects you see in you NLE. See your scopes? (Try a -1EV too!...just for the fun of seeing how bad the normalized video might look after you try to lift THAT in post)

CT

Doug Jensen
May 30th, 2016, 08:46 PM
That said it is frustrating Alister recommends shooting 1-1.5 stops above the FS5's S-log exposure baseline. I assume he's correct.


Alister's over-exposure rule?! Surely, you've got to be kidding. He's finally just saying the same thing many of us have been saying for years -- that you don't really need 49 IRE of headroom above 60% just for highlights.

Everyone I know (who's work and opinion I respect) that shoots RAW or S-LOG with ANY of Sony's cameras (FS5, FS7, F55, F5) ignores Sony recommendation of 60% white. I don't know anyone who follows Sony's advice. In fact, in my FS5 master class video, that I produced many months ago, I specifically recommend 75% zebras on white for S-LOG (see chapter 12), which produces video that is 1.5 - 2.0 stops overexposed compared to Sony's guidelines. So Alister and I are saying the exact same thing. aAd when we agree on something, you know we must be right. In fact, that is the advice I've been teaching for at least THREE years. Exposing a couple of stops aboe 60% is standard operating procedure for everyone in the know. This not anything that came from Alister -- and if anything, he was late to come onboard with the rest of us.

Also, even at 75% you aren't going to "pull down the levels" in post. They are still going to be too low. You're always going to be bringing UP the levels from 75% to 90% -- or higher -- to get a finished image.

Furthermore, anyone who knows anything about grading S-LOG or RAW in Resolve also knows that you don't need special LUTs to compensate for exposure variations. That is all just nonsense. You simply adjust for exposure on the the first node and then apply a LUT (if you choose to use a LUT) on the second or third node. It's very simple.

If you want to shoot S-LOG, all you you to know is:

1) Choose S-LOG2 for uncontrolled light situations ( outdoors, run & gun, documentaries, wildlife, etc).
2) Choose S-LOG3 for controlled lighting situations (sit-down interviews, faces, drama, indoors, etc. )
3) Expose bright reflected whites at 75% by using zebra 2.
4) Always grade in Resolve (BTW Resolve is free so there is no reason not to have it)

That's all there is to it.

Cliff Totten
May 30th, 2016, 09:44 PM
I dont know about anything you and Alister might or might not have between each other. I can only tell you that he has been saying this for a while. This video is not the first time. I do know your excellent videos but I'm more familiar with Alister and I have been reading his site for a very long time. Alister has also been a Sony spokesman for a long time now.

I do think that Sony should give a couple of gamma assist options inside the camcorder. Like a +1 or +2 option.

For me? I protect my highlights like everybody else but I do often expose as much and I can safely get away with to see further into the shadows. (depends on the scene and how much I'm looking for) So, I'll press SLOG fairly hard to get as much as I can out of it and I have learned to get the results I'm very happy with.

My biggest advice to Nigel is try it at different levels and see how that affects his grade.(good and bad) Like you, Alister and others have said, you need to push it a stop or two, possibly more. For what I have seen? That's a huge difference in the grading experience. Noise can be nasty in SLOG so you do whatever you can to mask it on post.

The best way to learn SLOG (one of them) is to see what it looks like when it's screwed up in post.

Here are two SLOG-2 frames, before and after. Just two shots in my backyard on a VERY sunny day in Florida. There are shadows in both. Some cats in the tiki hut and very dark shadows in those elephant ear leaves. I shot this very hot with whites near 100 on the scopes with little "specs" reaching around 105-ish

Both theses wave forms were contrast stretched downward and brights lowered. (Nope these aren't perfectly broadcast legal, white balance is cold and this is a quickie. Never meant for anybody to see these!) This was a test a while back to see how far I could push the FS5 in both directions.

See here ----> https://drive.google.com/folderview?id=0B_6rlVR2jPsqY2NCTnlDYnUxSzg&usp=sharing

CT

Patrick Baldwin
May 31st, 2016, 01:41 AM
Just wanted to say thank you for this thread! As a new FS5 user and inexperienced in general this is incredibly valuable to me.

Cliff Totten
May 31st, 2016, 05:38 PM
Dont use SLOG on a paying job or serious job right now but also don't be afraid to experiment with it either. Honestly, SLOG is great, but there isn't a strong need for it in many common situations. I find it really only good for outdoor extreme dynamic range scenes. For indoor work I just can't imagine myself using it. And certainly if I have controll of lighting, I don't think it's necessary.

SLOG puts a strain on an 8 bit, highly compressed CODEC and why beat up that CODEC if you aren't going to reap that much benifit in the end?

Every scene is different and only you can really determine what the subjects exposure needs to be. Skin tones? A dark colored animal in front of a bright waterfall? A pure white orchid in a shady garden? A women looking out a sun lit window? Whatever it is, It's your call. It's your art. SLOG is just one tool to use. Experiment with it first with shooting and try many grades and coloring before you begin to rely on it for jobs.

CT

Doug Jensen
May 31st, 2016, 09:08 PM
I'm not disagreeing with the advice to do your own testing until you become comfortable with S-LOG or any other mode the camera offers, but I will say that shooting S-LOG shouldn't be scary. In fact, it's actually easier and more foolproof than Custom because it is so forgiving if you don't nail the exposure or white balance as closely as you'd ideally like. "Fix it in post" used to be a joke, but with S-LOG and the great 10-bit codecs we have at our disposal today a lot of stuff can be fixed . . . or improved in post. But with the Custom mode, things are a lot more baked in and harder to change after the fact. Of course the caveat is that you need to have some grading skills and decent monitors to get the job done right. You can't just blindly throw a LUT on all your S-LOG footage and walk away -- that's not grading.

Nigel Davey
June 2nd, 2016, 10:33 AM
Well I've put together 30 secs of clips from my first venture into S-log. It isn't perfect, but I've learnt a few things during the shooting and editing process.

Slog experiment 25p on Vimeo

When I have time I'll go back and edit some of the 709 clips from the same shoot to see just how far I can push them in Post.

Doug Jensen
June 2nd, 2016, 10:56 AM
Real nice. I think you have nailed S-LOG already.

Cliff Totten
June 2nd, 2016, 11:42 AM
Very nice. It's a very "warm" look with mild tones. The sky gradient is interesting too. Nice job. Nice movements. Where you on a jib and /or gimbal?

CT

Nigel Davey
June 2nd, 2016, 12:12 PM
Thank you both. But in reality I found it very difficult to get to this stage. Since I am (as yet) unfamiliar with Resolve I had to use Premiere. 90% of my footage had the flashing discussed in the other forum. With what was left I constantly had to battle a green tint, despite setting all three FS5 slog profiles to 5500K. Not sure why it was there.

In Premiere I started with Lumetri corrections but often had to resort to other correction tools. So on the whole it was not fun.

Doug I realise Resolve is probably the answer. I just need to carve out time to learn it.

Cliff, yes I used a small Kessler jib for verticals and a mini dolly for horizontals. I've considered a gimbal system like the Ronin, but may wait and see if an Osmo Mkii (I assume there will be one) is a little more user friendly. The sky is a straightforward gradient from my Red Giant Looks plugin.

Again thanks for the encouragement.

Cliff Totten
June 2nd, 2016, 01:39 PM
Color shifts are something I see allot with SLOG 2 but not very much with SLOG 3. It's my guess it's because SLOG3 is more linear than SLOG2?

I tend to play with curves for each RGB channel. I might say "Let me pull the mid-tone blue's in" or maybe later "brighten the low end green" A slight change to one channel will affect the other two.

Sometimes I increase the saturation so it's too strong first. This let's my eyes see where things are blatantly wrong or off. I then fix it in the heavily saturated look first, then after I think it's balanced, I pull back the saturation to where I think it's natural.

The grading tricks are endless. Everybody has their own way of getting there and there is no real "wrong" color grade.

OK,...yes, I think the only "wrong" thing you can do is to add a plugin that pulls a level down and have another that pulls it right back up behind it. If you stack plugins that stretch chroma/luma in "opposite" directions at the same time, they can pull an 8 bit codec further apart and cause too much separation. (competing plugins hurts banding)

Have you seen "Mad Max: Fury Road"? The yellows are VERY deep and explosions are extremely dark red/roange. The movie is extremely bold in its color grade. Then look at "The Revenant" That move is extra blue and cold whites and the saturation is reduced to create a desolate, dark "feel". It's the exact extreme opposite of "Mad Max: Fury Road". Both are extreme and both are great.

Resolve is awesome. But you can color grade with many products. I think it's more about training your eyes to spot what is wrong and learning to shift things in the real direction you want them move. Sometimes I say "Yuck,..I dont like this tint/color so I'll tend to "push away" (very lightly) form that color into the direction it's opposite color. So if I say" Ehhh...too green"...I start pushing CAREFULLY over to the red or violet or orange direction. If you dont like a tint head to it's opposite color to balance it. Every NLE has a brights wheel, a mid tone color wheel and a shadows color wheel. They are your friends.

I think that grading Slog takes more practice than learning to expose it in the field. That's why I say the SLOG work flow requires two different skills.

CT

Alfred Okocha
July 1st, 2016, 05:37 AM
If you want to shoot S-LOG, all you you to know is:

1) Choose S-LOG2 for uncontrolled light situations ( outdoors, run & gun, documentaries, wildlife, etc).
2) Choose S-LOG3 for controlled lighting situations (sit-down interviews, faces, drama, indoors, etc. )
3) Expose bright reflected whites at 75% by using zebra 2.
4) Always grade in Resolve (BTW Resolve is free so there is no reason not to have it)

That's all there is to it.

Hi there!
I just got a job for next week where I'll shoot s-log for the first time. (S-log 3 to be specific.) I won't grade it, they'll have experienced people for that. I just want to know I get the exposure right.

I just went out and shot some seconds using Dougs third rule up there. I applied the pre made SONY s-log 3 in FCPX and the exposure looks quite right. (I brought down the highlights a little notch since they were a bit over 100%)
1. Is it really that simple? (Considering all the warnings everywhere about shooting it.)
2. What should the zebra 1 be set at for skin tones?
3. They want some shots at late evening. Any tips?

Thank you very much!

Alfred Okocha
July 1st, 2016, 05:46 AM
Here's a screen shot by the way.

Doug Jensen
July 5th, 2016, 07:47 AM
2. What should the zebra 1 be set at for skin tones?


None. You don't expose for skin tones because everyone's face is different.

Cliff Totten
July 5th, 2016, 12:36 PM
Hi there!
I just got a job for next week where I'll shoot s-log for the first time. (S-log 3 to be specific.) I won't grade it, they'll have experienced people for that. I just want to know I get the exposure right.

I just went out and shot some seconds using Dougs third rule up there. I applied the pre made SONY s-log 3 in FCPX and the exposure looks quite right. (I brought down the highlights a little notch since they were a bit over 100%)
1. Is it really that simple? (Considering all the warnings everywhere about shooting it.)
2. What should the zebra 1 be set at for skin tones?
3. They want some shots at late evening. Any tips?

Thank you very much!


Just out of curiosity, what camera are you shooting SLOG-3 with? Are you using the internal CODEC or are you shooting with an external recorder? SlOG-3 is extremely tough on a long GOP 8 bit CODEC. That's allot of contrast stretching on the other side to normalize it. ProRes 8 bit won't help banding problems too much but can help with compression artifacts.

One tip: Shoot only at 0db or the lowest ISO allowed. If you are in low light, and need brightness, it's much better to open up and let more light in than it is to add any gain.

For lack of a better term, SLOG "compresses" the gamma brightness. Or, another way to think about it is, SLOG "suppresses" brightness by certain ratios.

In bright light, this is fine, but in low light? SLOG is going to fight you back and make getting more brightness difficult. Remember, ISO/Gain is not "light"....only shutter and IRIS give your sensor more light.

ISO/gain is only a "post" process that is done later, after your sensor is done with the light it collected.

If you are wide open and your shutter is as slow as you dare to go and you STILL can't get enough brightnesss at 0db?....it's probably best to switch back to a rec709 gamma and not use SLOG for that shot. You can then crank up your gain and not be slammed with a ton of noise.

CT

Alfred Okocha
July 5th, 2016, 06:28 PM
Thanks Doug and Cliff!

No zebra 1 for skin tones. No gain! I'll use the FS5. It's the client that asked for slog3 but I'll only use it when there's enough light then.

Seems straight forward, just wonder what kind of lesson I'll learn the hard way...

To something different, if I have understood things right it's better to overexpose than underexpose since it's fine to bring the curves down and no noise is added, with s-log. When you underexpose and bring the curves up you'll get a lot of noise. Correct? Have I understood that correctly? If so, why don't we set zebra 2 to over 100%? 110-120 or whatever? I'm I making some kind of mistake here?

Cliff Totten
July 5th, 2016, 08:39 PM
I totally wont give you any advise on zebras 1 & 2. I'll let the others do that for you. Everybody has their own experience.

For me zebras are vital measurement tools. They tell you what objects are sitting at what brightness levels in the spectrum. You have two choices for each zebra:

1.) What object are you measuring?
2.) Where do you want that object to live on your scopes?

What objects you "should" care about and where you think they "should" belong on the scopes is totally your creative call. You can watch 100 commercials on TV and second guess their exposure all day long. It's funny,..ever tired doing that?...."Nah,...too bright,..too dark,...OK, just right" You can do it with movie scenes and drama's or commercials...it's endless. What I think is under exposed, someone else thinks is perfect and so on.

For me? I use different values for different things, I dont do things exactly one way only ALL the time. For me it's very "scene dependent" and sometimes I deliberately shoot a stop over or a stop under based on the narrative of the scene.I just cant subscribe to the "do something this one way and you will always be safe" idea. You have to develop good judgement and learn to trust it over time.

For SLOG, yup 1.5 or 2 stops over. (often, but not guaranteed all the time) When grading, it's beneficial to stretch contrast in a "downward" direction. If you ever have to stretch "upward" you are going to bring noise that is already high, even higher.

You can press SLOG-2 to see deeper into shadows and increase your DR but whatever you see jammed up into the top, (if you do, like clouds or strong whites) could be tough to recover because there is a bit higher gamma compression up there. So whites can sometimes get smashed even though they are not exactly clipped per say.

SLOG-3 clips much lower than SLOG-2. (I think 94 IRE?) So dont expect to see any zebras if they are set higher than 94. SLOG-3 is easier to grade because it's more linear that SLOG-2. It doesn't "arc" as much. It's pancake flat and your deepest black is,...jeesh....15 IRE? Test it because I dont remember exactly.

Please shoot a few test hours of SLOG first before you do a paying job. Also, knowing how to grade it in post will help you shoot it in the field. Honestly, and this is just me, I dont think you can shoot SLOG in the field without have some experience grading it. In my mind, the two must go together. Maybe that's just me but when I shoot SLOG, 50% of what is going through my mind is as I shoot: "OK, I'm doing this or that to this shot with my tools in post" as I watch it. I dunno, maybe that's just me.

Oh,....dont under expose SLOG-3 or your colorist will kill you....especially with the FS5. ;-)

This is just my $.02 on SLOG. Others with have their own advise. Take it all with a grain of salt as you will learn more from shooting hours of SLOG and grading it for hours and hours. That's where you really learn it and develop your instinct.

CT

p.s. To be completely 100% honest, SLOG-3 is not really designed for 8 bit. It really requires 1024 steps per RGB channel instead of 256. If you are not the one grading it, and your client is asking for SLOG-3, make sure he/she is aware that you are delivering 8bit files. (unless you have a Shogun with the FS5 raw license) It would be really bad if the colorist was expecting 10bit.

Alfred Okocha
July 6th, 2016, 08:24 AM
Thanks Cliff!

After some more testing it seems that skin tones is a lot trickier than a general view image.
Since I'm a grading dummy I just tried to do some basic grading to see what could come out of it. Is this a valid way of testing, does it give a grading expert an idea what he has to work with? I did the following; I imported in FCPX applied an osiris log LUT and expanded contrast until the whole spectrum was filled and then cranked up the colours a bit.
I realise that the end result in it self is questionable but if you had this image, could you work with it in a proper way?

Thanks!

Cliff Totten
July 6th, 2016, 09:33 AM
I'm at work so I'm not in front of Premiere or Vegas.

Look up tables only get you in the ballpark. You gotta go the rest of the way on your own. ;-)

What was your FS5 white balance setting?. Can you upload 1 frame of SLOG-3 and I can play with it when I get home? Did you shoot any rec709 of the same scene?

CT

Alfred Okocha
July 6th, 2016, 09:56 AM
I shot a similar view with rec709.
Can I upload an XML frame or do you need the original file for that to work?

Alfred Okocha
July 6th, 2016, 10:22 AM
Let's see if this works...
No, can't upload... "Your submission could not be processed because a security token was missing."
Don't know what that means. The file's just 8mb so it should be possible I think...

My WB was 5200. Does it make a big difference if you shot that instead 3200? I heard that 3200 has more info, but it hurts a bit to shoot it that way...

Cliff Totten
July 6th, 2016, 10:36 AM
WB can be shifted in post but I certainly would use a temp that matches closest to your actual scene. I mean, I wouldn't shoot anything extra cold or warm to try gain anything from that. The less 8bit correction you need to do in post the better!

Do you have a Google drive that you can post a single frame .jpg to?

Alfred Okocha
July 6th, 2016, 02:10 PM
No Google drive but I can e-mail you them if you give me a mail.

Alfred Okocha
July 6th, 2016, 02:25 PM
Not sure if these will do but...

Cliff Totten
July 6th, 2016, 07:09 PM
So I grabbed your frame and did a quick grade on it. I didn't use any LUTs, just high, mid and low color wheels, AAV color lab and a touch of sharpening. In AAV, I adjusted green channel saturation and shifted slightly in the blue direction and darkened yellows a bit. Mid tone color wheel was swung a bit towards red and overall saturation increased allot.

It's just a simple, plain "mild" look, I think with a modest contrast. Nothing at all special. It's not broadcast legal 16-235, there is some that dips under 0 but who cares for this? hehe

This one is has less contrast with lighter shadows:
https://drive.google.com/file/d/0B_6rlVR2jPsqYjlVR0lCbzBPdkU/view?usp=sharing

This one has more contrast with more crushed blacks: (center of contrast lowered)
https://drive.google.com/open?id=0B_6rlVR2jPsqZGF4VGI0YkhfZkE

This last one has a LUT and has bold contrast. I kept this one basically between 0 and 100
https://drive.google.com/file/d/0B_6rlVR2jPsqSzJxREFGdWZvSEU/view?usp=sharing

Another with more contrast and blue water pulled back:
https://drive.google.com/file/d/0B_6rlVR2jPsqa3dVdG5DbHkzZmc/view?usp=sharing

Alfred Okocha
July 6th, 2016, 07:53 PM
Nice work Cliff!

I'm partial to high contrast so I liked the last one best but the others are nice too!

I guess you had all the data you needed within the frame then, so I guess I got the exposure right for this one?

Thanks for your help Cliff. Very valuable to me!

Alfred Okocha
November 22nd, 2016, 05:38 AM
Hi there!

I've now been shooting with s-log 3 a bit more with varying results. It is a bit of a learning curve for sure. Both under and overexposing does not look good, at all.
I know you all say to expose for whites instead of skin tones but that has put me in trouble where I had to bring the mids up a bit and, as some one said here, welcome to noise city...

Since I do a lot of talking heads the most important for me are skin tones. If anything else is too bright I'll deal with it another way in post. (Is it really just me that prefers to adjust the iris to skin tones and not whites when you shoot log?) What would you put for zebras on the high lights on a caucasian when you shoot s-log 3? 75, 80 or even 85?

Thanks a lot for all your help. It has really made a difference!

Doug Jensen
November 22nd, 2016, 01:23 PM
What would you put for zebras on the high lights on a caucasian when you shoot s-log 3? 75, 80 or even 85?

None of those. I would never set exposure based on skin tones. Is everyone's face the same shade? No. So obviously a face is not a consistent target and should not be used to judge exposure. Otherwise you are just guessing at the exposure, and your eyes and EVF will fool you often. Why do we even have zebras, light meters, waveforms, etc. if it's just going to come down to guessing anyway? You must use bright white, a genuine 18% gray card, an incident lighter meter, or some other method that ensures you are being consistent and accurate.

Bright reflected white, measured with the zebras, is by far the easiest method of setting exposure for S-LOG and that's pretty much all you should need 99% of the time. But an equally important part of the equation is how you process the footage in post. It's good that you're showing concern for getting the exposure correct, but you haven' said a word about what you are doing to the footage in post. You can't expect good results with S-LOG if you don't have a good workflow in post.

https://vimeo.com/ondemand/resolve

Alfred Okocha
November 22nd, 2016, 02:34 PM
Hi Doug!

I understand that what you are saying is undoubtedly correct about how to expose properly. I do a lot of ENG work however. I work alone in environments that may change. England is overcast one minute and a bit sunny the next. Most of the time there is little to no time to set things up properly.

You may say that that's why we have rec709. But, there's ever pressure to deliver better, visually more interesting material. That's why I'm moving to s-log, when I know I have some time to color it before it's sent, that is.
I'm doing the post work myself with Color Finale. It works well for me I think. And I don't have to export in and out of FCP which is a good thing, for me.

Doug Jensen
November 22nd, 2016, 04:16 PM
That is all the more reason why you need to have a fool-proof, fast, easy, way of determining the right exposure without guessing. Guessing and second-guessing wastes precious time during the shoot and also later in post to fix inconsistencies. If you learn to expose on reflected whites with zebras, you will instantly be faster and more accurate.

And BTW, S-LOG is much easier to expose than rec709 because it has so much more leeway and dynamic range. If someone can't mostly fix a poorly exposed S-LOG image in post, then they really missed the exposure!

I can't speak about Color Finale because I never used it, but I haven't seen any color correction tools in any NLE that are good enough for grading S-LOG properly. If someone is going to shoot S-LOG they really need to commit to using a dedicated color grading program such as Resolve, Baselight, or similar. The difference is night and day in terms of what you can do and how fast you can do it.

Nigel Davey
November 23rd, 2016, 04:26 AM
One way I'm exposing Slog 2 is using a SmallHD 501 monitor and setting one of the screens/profiles for zebras between 0-40 IRE, another screen for 40-70 and the third to 100-109.

If you are familiar with the SmallHD interface you'll know you can quickly flick sideways between all 3 screens. Thus getting a quick look at what will be noisy in the shadows, what should grade well and what will burn out.

If you want to eyeball it (which I know will send Doug crazy;-) you can apply a live LUT on yet another screen.

But I must admit going the SmallHD route is an expensive option and personally I've had quality issues with two of their units, so not all plain sailing.

Alfred Okocha
November 24th, 2016, 12:01 AM
Thanks guys!

I really appreciate it!