Flaat for the a7s

Samuel H

Samuel H

Major Contributor
Not something that you can install on the camera, just a suite of settings that I like:
* Use PP7 (reset it if you have been fiddling with it before)
* Color Mode = Cinema (s-gamut3 has issues, cinema is better)
* Set Saturation = +15 (better bringing it down in post than up)
* Set Color Depth = 0 +1 0 +5 -3 0 (for each of RGBCMY)


It has the wide DR and the nice light-response function of S-log2:
waveform_a7s_slog2.jpg


It has very accurate colors (based on Cinema, but with a lot of extra saturation and some tweaks):
spydercheckr_9_flaat.jpg


And it looks great right out of the camera: this test video is ungraded


Read more about it here: Flaat for the a7s


(sorry, I forgot to shoot K-log and macgregor's cine4 profile when doing the color test; I used all the PP slots for different variations that I was trying, and forgot to shoot again when I had everything nailed down; I promise I will do it, eventually...)
 
Looks great, man. Nice and clean. That saturation punch was a good call. Looks more like slog on the higher end cams now. Sharpness tweaks at all?
 
Looks good Samuel - just to be clear, you overexposed a bit according to the camera, but did not change the exposure in post? Did you apply something for the superwhites, or is this, as you said, exactly as shot, no changes whatsoever?
 
Making it difficult for me to hold out on a camera this season! =)
 
So, a few things...

* Something broke in my site, all the images are down, I'll be fixing it tonight.

* @cyork: no sharpness tweaks at all, just set at the PP7 default, which is basically "minimum". I played with it trying to get rid of the highlight aliasing issue, but couldn't manage, so I let it be.

* @wallrc: no exposure changes whatsoever in post (no superwhites adjustment needed because the slog2 gamma doesn't go beyong IRE 100). Changes in exposure in the video are because I was trying to see how much overexposure would be best. My conclusion: +2 or +3 can be too much at times (there's some color clipping in some shots, and they look bad; this can still happen with not-so-high saturation values in camera), 0 is too low (noisy and with less headroom in the shadows), +1 is going to be my target. (BTW, that is +1 using the camera's internal spot meter and a grey card, I still have to play with my light meter to make sure everything lines up as it should)

* @jhero: Pro is very nice too, and I guess it can also be tweaked to look very similar to this. I just went with Cinema first, and ended up linking my final tweaked Cinema over the standard Pro colors.

* @Mad Marvin: sgamut2 is surprisingly nonlinear in the skin tones: hue changes with exposure. I think this is what causes the yellow splotches in skin that some people were complaining about early on. There's a very good test in this thread here. And check how the third skin tone patch in this test suddenly is too yellow:
attachment.php
 
For that El Escorial video I used the camera in my "nearly pocketable" setup: bare camera, Leitz Summicron-C f/2.0 lens, Hoya ProND 500x (9 stops). I shot at apertures ranging from f/2.0 to f/8.0, but mostly at f/2.8 and f/4.
 
Am I seeing a magenta cast, especially in the sky/clouds?
Overall avery balanced look.

Strong movements look still very DSLRish. :(
 
Your eyes are probably more sensitive than mine, but I'm not seeing anything.

Also:
* In case the proND or the lens had a color cast, I used custom WB with a grey card.
* I tested Flaat against the spydercheckr, it's one of those pics that should be seen in the first post here but are down because something broke on my site; I'll fix that tonight.
 
I love the work you do really drilling into these cameras features and sharing it with all of us. What happens to this saturated footage when you have to apply a film emulation LUT like ImpulZ or Filmconvert on your footage? Do you still get good results even though they've been tweaked for the real desaturation of slog gamut?
 
Demistate said:
I love the work you do really drilling into these cameras features and sharing it with all of us.
Click to expand...
+1
Really appreciated.
My a7s camera comes next week and I am very thankful for people like Samuel who test and share their findings with the rest of us.
 
Demistate said:
I love the work you do really drilling into these cameras features and sharing it with all of us. What happens to this saturated footage when you have to apply a film emulation LUT like ImpulZ or Filmconvert on your footage? Do you still get good results even though they've been tweaked for the real desaturation of slog gamut?
Click to expand...

In my own experiments, using LUT's (including those designed for the A7s by Alister Chapman) on footage that has anything but slog for color results in crazy crazy technicolor. Film convert has so many setting that many of them are just fine, since a lot of the settings were designed for regular footage.
 
* Web fixed, you can check all the tests now. Here.

* LUTs should work... with caveats. First, before you apply the LUT, you'll have to desaturate your footage; but doing this in post leads to better color information than doing it in-camera. Second, there will be some color shifts, because of the tweaks I did to the Cinema color map, and because it is actually Cinema and not Sgamut, which is what many LUTs will expect. There's a lot more difference between Sgamut and Cinema than between Cinema and Flaat, so if you're willing to use a LUT on Cinema you may as well use it on Flaat.
Having said that, I'm not a big fan of LUTs. My usual correction+grading workflow is: adjust WB if needed, adjust black and white levels, add curve to adjust exposure and contrast, add Magic Bullet Mojo/Cosmo/QuickLooks. Then add 0% Mojo to check that final skin tones are correct.

* Stu Maschwitz says my video shows some color clipping. I think it's only in the clips where I overexposed too much (I was testing exposure too, I concluded +1 is probably the sweet spot, +2 can be fine but only sometimes, +3 is bad), but I will have to test this thoroughly. In the meantime, maybe Saturation +10 or +12 instead of +15 is not such a bad idea if you're shooting an important project... (I have 3 things to shoot this weekend, I better hurry with my tests!!)
 
Last edited:
I also use the A7s with the Leica 40mm. I think it's the smallest possible combo you can have if you want a fast, full frame lens.
 
It's a very nice lens in general, I haven't tested it yet scientifically but it feels sharp when closed down a bit. And talking about feelings, the a7s+summicronC combo just FEELS RIGHT in my hands, just as if it was a rangefinder.

Investigating further into the saturation issue (is +15 too much, as Stu said?). Later today I will upload two new versions of the El Escorial video, one that is color corrected (just fixing the exposure), and one also graded. I see no color issues once I correct exposure, but I'll let more experienced eyes be the judges of that.
 
I'm using my A7s with a Konica Hexanon 40mm F1.8. Love 40mm field-of-view on full-frame (28mm on APS-C) - my personal favourite :)
 
You must log in or register to reply here.
Back
Top