a7s slog2 is really, really flat

[caseywilsondp]

hey guys just wanted to post some screen shots of the a7s filming in slog2.

just got the camera and waiting for all the gear to arrive before i really put it through its paces, but I wanted to see how it's footage in slog2 handled compared to say r3d files or arri raw.

first, slog2 is really really flat. this is the first dslr i've owned since my 5Dm2 many years ago, and i thought cinestyle was flat for dslrs... this appears much flatter. i grade r3d files a lot and it makes redlogfilm look a bit crunchy by comparison.

here are some pics of my wife hanging out in the living room. as tests go, it wasn't very fair to the a7s. under-exposed, mixed light, non IS lens... (first time i used the camera essentially, just attached a lens and shot what as around me.

the first image is right out the camera. the next has an off-the-shelf kodak 2383 film print LUT applied:

the last two are my attempt at grading a 'natural' look and finally an aggressive 'cinematic' grade:

slog2 is not one of the more easy logs to grade in my opinion. the 'natural' look took me quite a while, and I'm still not 100% with it (but I think it's close enough to know it could get there).

that being said, the log takes a film print LUT really nicely. I'd probably shift the color temp a little bluer, but I wanted to show how it looked pretty much with no work done to it.

the 'cinematic' grade i really just wanted to push contrast and see how crushed and inky the blacks could look, and how high i could push the mids and highs while keeping information.

had I exposed a bit better, I probably could have gotten more out the mids and highs, that being said though, i feel the footage, for not being raw, handled pushing and pulling OK. slog2 at least lets you push it pretty far, but once you've gone too far it let's you know pretty quickly and it's pretty ugly (raw files from red and arri are a bit more composed at you push them beyond what they'd like).

while in my professional career have been starting to shoot more on the F series of sony cameras (fs7, f5) and less with red and arri, i've never actually gotten a chance to grade sony footage, and while I know this isn't the same as grading footage from the F5, it's still I think a good idea of what the image will look like, which is one of the reasons I decided to pick up the a7s.

anyways let me know what you guys think, and if you have any tips or tricks when it comes to slog2 in post.

(btw, nikon 28-70 at a 2.8, graded in speedgrade). 

[Guest Ebrahim Saadawi]

I actually think you did a great job here. The first grade is quite natural with lovely film-like skin colour. If you find it's too hard too grade the flat image, there are many other profiles on the A7s that start with a much more pleasing image for minimal grading (Cine 4, etc)

[caseywilsondp]

thanks I appreciate that. I've heard the other PPs are quite a bit easier, but I'm going to keep trying out slog2 for a while to see if I can get used to it (the extra dr is the main reason). the shogun arrives today, and I hear that's another level of difficulty when trying to keep all the info the camera is trying to spit out.

the main problem i foresee is that when shooting say on the epic i'll put in a look that the director and i choose for the shoot, and i'll expose and light for that, but i always know that all the raw info is there so we can tweak it in post. i guess i'll have to pick a PP and light/expose for those, then switch over to slog before shooting?

anyone have tips for that?

[Guest Ebrahim Saadawi]

If you mean monitoring, and you're going be shooting with the Shogun, it has a monitoring LUT function where it transforms the S-log2 to Rec709 with pleasing image on the Shogun screen while recording the S-log image to the SSD, this is the best option for client/director on-set viewing,

Let's share what we find with the A7s:

What I am finding with the A7s, the best way to expose the image is simply set the Zebras to 100+ and expose the the extreme right without clipping highlights. I've kept reading technical articles on optimum S-log exposure with specific scientific IRE numbers and science talk, yet from my tests, exposing to the right just gives the absolute best image. Perhaps getting a normal/darker exposure is wanted if there's no colour grading involved and will hand over to direct viewing. Anyway, just expose to the right for best noise and colour performance.

Regarding Colour: before I got my hand on the A7s I had the impression the a7S produced terrible colour rendition, especially of peoples' skin, and to be honest, this is true to an extent, but I found it's also quite easy to "fix" in post yet all the video samples just didn't fix the S-log2 files to give pleasing skin. When you give consumers professional Log Gamma, you're bound to be flood with hundreds of horrible looking images!

The main issue is this, there's simply a green/yellow cast in the midtones/shadows where skin tones live, it's the issue that's giving the immediate impression of bad skin tones on the a7S, people are yellow or green, and it's not a white balance issue, just how the camera sees colour. Canon and Nikon cameras give natural red/magenta people straight and so we end up with more good looking images on the web. People much prefer to have a lively red/magenta colour vs yellow/green and dead.

So my fix was simple, use the Three way colour corrector, and take out the green/yellow cast by moving the mid/lows slightly to the blue/magenta area, until you get a pleasing normal looking skin tone. Then bring the saturation to the desired point, and tweak the skin as desired from there. Just get rid of the Sony yellow/green trademark and you're fine. Just don't over do it and get red-second-degree-burnt -people-look. 

Here's what I mean:



You start with the over-exposed flat image, so you first correct the gamma with an S-curve to your liking, avoid LUTs and do this manually, very easy to get your exact desired luma levels.



Now I remove the yellow/green cast by moving the colour wheels towards magenta/blue



Then saturate the image to the desired point, ending up with normal slightly pinkish/reddish healthy-looking skin



now if you had skipped the removing yellow cast step and directly added saturation, you'd get the typical a7s look floating on the interweb



Horrible colour, at least to me!

So I am finding the a7S colour issue to be all about slight thinness and yellow/green tints. And also the blue highlights clipping. 

In the end we have to remember colour grading is subjective, and what I like could be entirely hated by any(or every)one else. So grade to your own liking. Does a Canon or a Nikon save you all this trouble and makes you produce healthy skin straight off the card with a simple grade? YES, but where's the fun in that. I like a challenge 
 

[Ivar Kristjan Ivarsson]

Very nice little tutorial Ebrahim. Thanks alot

[Hitfabryk]

hey guys just wanted to post some screen shots of the a7s filming in slog2.

just got the camera and waiting for all the gear to arrive before i really put it through its paces, but I wanted to see how it's footage in slog2 handled compared to say r3d files or arri raw.

first, slog2 is really really flat. this is the first dslr i've owned since my 5Dm2 many years ago, and i thought cinestyle was flat for dslrs... this appears much flatter. i grade r3d files a lot and it makes redlogfilm look a bit crunchy by comparison.

here are some pics of my wife hanging out in the living room. as tests go, it wasn't very fair to the a7s. under-exposed, mixed light, non IS lens... (first time i used the camera essentially, just attached a lens and shot what as around me.

the first image is right out the camera. the next has an off-the-shelf kodak 2383 film print LUT applied:

the last two are my attempt at grading a 'natural' look and finally an aggressive 'cinematic' grade:

slog2 is not one of the more easy logs to grade in my opinion. the 'natural' look took me quite a while, and I'm still not 100% with it (but I think it's close enough to know it could get there).

that being said, the log takes a film print LUT really nicely. I'd probably shift the color temp a little bluer, but I wanted to show how it looked pretty much with no work done to it.

the 'cinematic' grade i really just wanted to push contrast and see how crushed and inky the blacks could look, and how high i could push the mids and highs while keeping information.

had I exposed a bit better, I probably could have gotten more out the mids and highs, that being said though, i feel the footage, for not being raw, handled pushing and pulling OK. slog2 at least lets you push it pretty far, but once you've gone too far it let's you know pretty quickly and it's pretty ugly (raw files from red and arri are a bit more composed at you push them beyond what they'd like).

while in my professional career have been starting to shoot more on the F series of sony cameras (fs7, f5) and less with red and arri, i've never actually gotten a chance to grade sony footage, and while I know this isn't the same as grading footage from the F5, it's still I think a good idea of what the image will look like, which is one of the reasons I decided to pick up the a7s.

anyways let me know what you guys think, and if you have any tips or tricks when it comes to slog2 in post.

(btw, nikon 28-70 at a 2.8, graded in speedgrade). 

​Make's a lot of sense, I like the natural as well as the filmic look. Thanks for posting.

[Ivar Kristjan Ivarsson]

​Make's a lot of sense, I like the natural as well as the filmic look. Thanks for posting.

​Me too

[caseywilsondp]

Ebrahim, totally forgot about the shogun allowing luts, so that'll be great! Also thanks for your mini tutorial, I'll try your recommendations when exposing when I try the camera out again.

[Guest Ebrahim Saadawi]

http://www.dvxuser.com/V6/showthread.php?329312-Yellow-highlights-here-is-a-solution

I found this interesting too as it seems the yellowy skin tones is an inherent part of the Sony colour science in all their cameras, here the FS100 seems to produce yelloish skin which really looks identical to what I've been getting with a7s. Someone here on DVX gives a more complicated solution by selectively desaturating the highlights and mids to put the yellow down (feature in resolve, if anyone has it please give us insight on how this works with the a7s yellow footage)




Anyway after some testing with the a7s vs d810 and Canon 60D, colour science differences doesn't seem to be as big of an issue as people make it seem, it's just a few minor changes in how the cameras see one colour or two/three max. With the a7s it's yellow and blue, they're slightly different from Canon giving the Sony look especially to skin. For example most of the other colours seem identical to Canons (greens, browns, orange, blacks, purples etc) so shooting anything that doesn't envolve people looks very Canon like. These minor colour differences could be a huge problem for those of us who don't colour grade thier footage, and want direct nice skin, but I can spend some time tweaking S-Log on my own personal work, it's where the fun lies! When I have a deadline and paying clients I'll use these fast/easy to grade cameras since most clients don't see the resolution/DR/noise advantage of the a7s and just want good looking people.

Let's post our before/after grabs colouring results of S-Log2 and explain briefly what's been done (hopefully with skin as this is where the issue lies), this would very helpful for us colour noobs 

[Guest Ebrahim Saadawi]

You can also embrace the Sony look if you want, here for example I was filming kids on the countryside playing and having S-Log-y yellow sun and skin was very appropriate to the footage



I could have never achieved this with a Canon/Nikon, not in sharpness, noise, DR, colour and most of all having a bulky pro DSLR would have intimidated people who have never seen such devices, the a7s just looks like a phone or so!

[Tim Naylor]

Ebrahim, good stuff. Love that step by step tutorial. Casey, just remember to expose to the right. I get as right as I can to the clip threshold. Also, I like screwing around with the pre-sets in camera such as boosting saturation and magenta signal (ever so slightly) in both S Log or PP6. I find this gives me a signal I can bend to my tastes better without breaking down or looking so "thin".

[caseywilsondp]

This is a great shot, and maybe a key to how we should be lighting with this camera. Warm backlight with a cooler fill and key... Almost the opposite of how I'd light with film or Alexa.

[Andrew Reid]

http://www.dvxuser.com/V6/showthread.php?329312-Yellow-highlights-here-is-a-solution

I found this interesting too as it seems the yellowy skin tones is an inherent part of the Sony colour science in all their cameras, here the FS100 seems to produce yelloish skin which really looks identical to what I've been getting with a7s. Someone here on DVX gives a more complicated solution by selectively desaturating the highlights and mids to put the yellow down (feature in resolve, if anyone has it please give us insight on how this works with the a7s yellow footage)




Anyway after some testing with the a7s vs d810 and Canon 60D, colour science differences doesn't seem to be as big of an issue as people make it seem, it's just a few minor changes in how the cameras see one colour or two/three max. With the a7s it's yellow and blue, they're slightly different from Canon giving the Sony look especially to skin. For example most of the other colours seem identical to Canons (greens, browns, orange, blacks, purples etc) so shooting anything that doesn't envolve people looks very Canon like. These minor colour differences could be a huge problem for those of us who don't colour grade thier footage, and want direct nice skin, but I can spend some time tweaking S-Log on my own personal work, it's where the fun lies! When I have a deadline and paying clients I'll use these fast/easy to grade cameras since most clients don't see the resolution/DR/noise advantage of the a7s and just want good looking people.

Let's post our before/after grabs colouring results of S-Log2 and explain briefly what's been done (hopefully with skin as this is where the issue lies), this would very helpful for us colour noobs 

​That's interesting to hear from Art Adams at DVInfo about the luma vs saturation of blues.

Film can't do a bright saturated blue.

Alexa caps saturation to avoid the same clipping problem of bright blues the Sony cameras suffer from.

That's where the knowledge of film comes in useful. Take a hint Sony.

[Inazuma]

Anyway after some testing with the a7s vs d810 and Canon 60D, colour science differences doesn't seem to be as big of an issue as people make it seem,

​Aren't you the one that gave up on certain cameras because of the colour science?

[Andrew Reid]

The problem I am having with the A7S is that - yes - colour can look lovely after a lot of work grading in post BUT and it's a bigger but than Beyonce's, you can't apply the same grade to every shot, every lighting circumstance needs it's own 2 hours of fiddling in Resolve. That for me is intolerable really. Also the bright-blues clipping issue is a problem, whenever I happen to have a blue light in the background of the shot I can no longer do what I want with the exposure, I have to "manage the problem" and it becomes tiresome.

Still love the A7S, it's great for the price but I need colour that's quick to get right and internal 4K, it is not giving me either sadly.

[Guest Ebrahim Saadawi]

​Aren't you the one that gave up on certain cameras because of the colour science?

​Yup. Don't tell anyone I am changing my mind 

[Andrew Reid]

Not allowed to change your mind on the internet about cameras apparently

1D C CLOG:

A7S SLOG 2:

Not good is it?

When I originally reviewed the A7S I loved the colour, from picking out the odd shot here and there.

Afterwards I spent months developing my own LUTs in Resolve that I could blanket onto an entire sequence in Premiere.

Didn't work because each scene / lighting needed their own nob fiddling.

[j.f.r.]

S-LOG on A7s XAVC-S , this codec is so good you can basically grade it how you want....... As soon as you learn and understand how to grade using RGB curves you will see exactly what it is you need to do. Two frame grabs from a project I am editing which I also shot in S-LOG A7s Iso 3200.

 

 

[Guest Ebrahim Saadawi]

 

Afterwards I spent months developing my own LUTs in Resolve that I could blanket onto an entire sequence in Premiere.

Didn't work because each scene / lighting needed their own nob fiddling.

​The ugly blue channel clipping showing it's face here!

What a shame a company like Sony allows such a significant flaw in their sensor. 

I haven't been bitten by it however, yet.

You frames here show the entire problem with the a7S colour science, blue clipping and yellow/green tint in the mids/lows, not just a tint, even some yellow "blotches".

Look how the desk looks apparently red/magenta on the 1Dc while the a7s is rendering it as absolute yellowish green? That yellow tint is the core of the skin problem in the a7s.

A typical Sony yellow skin is perfectly represented in the last frame posted by J.F.R above (Love the first shot btw)

[Hitfabryk]

You can also embrace the Sony look if you want, here for example I was filming kids on the countryside playing and having S-Log-y yellow sun and skin was very appropriate to the footage



I could have never achieved this with a Canon/Nikon, not in sharpness, noise, DR, colour and most of all having a bulky pro DSLR would have intimidated people who have never seen such devices, the a7s just looks like a phone or so!

 

 

​Hello Abrahim,

Which lens did you use here?

I Like the colors and sharpness.