FS7: Filming SLOG 3 at night with the FS7.

Amadou

Amadou

Carbonite Member
We are filming night scenes on the FS7 using SLOG 3 and a 709 Lut. Zebras are set at 70 and base ISO at 800. Many of the scenes are lit with 800 watt tungsten lights. In most cases even with the lens wide open at 2.8 we still are without zebras. On the viewfinder the image looks great. But since grain in the blacks may be a problem later, I tend to press the gain switch to 1600. This adds noise and often still does not reach Zebra level. At 3200 the lmage seems to pick up a lot of noise but the zebras start to show up. So the question is the following: Do I trust the viewfinder or only the zebras? My feeling is that SLOG 3 is useless in night scenes as the Zebras are almost never reached and since the dynamic range is very small anyways. Yet I dont want to switch back and forth between SLOG and regular video during a production. So should I trust the viewfinder or should I hit the gain switch?
 
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Are you in cine gamma? If so, what you are seeing in the viewfinder with the 709 lut is emulated exposure... as in, what you'd get in post if you were to gain up the footage.

If you are in custom then you woule indeed be able to raise the gain in camera. I think iso 800 at night might be a bit optimistic with the fs7.
But the camera is native iso 2000. Id have no problems going to 3200 in custom and "fix in post". But a nice start is to always try to overexpose the fs7 by 1-1.5 stop.

Thats why some of us tend to EI 800 (or 1000) in slog 3 with cinegamma. Cinegamma is always iso 2000, so by lighting our scene to 800 we make sure the shadows stay relatively noise free. But this means; sometimes its not the lights that determine our camera settings but our camera settings that determine what lights we need if any.

Are you able to cheat the light a bit between totals and close-ups? So the charactera might be sligthly underlit in totals but the lights serve the scene and mood and then move the lights in closer for your close ups?

EDIT: About lights... you wrote 800w, are you using them hard? I'm taking those are blonds. But if you are shooting them through diffusion or bouncing them, then ofcourse you aren't getting 800w worth of light on your subjects. I don't think you can say that slog 3 is useless at night... I mean, any camera will suffer with too little light. Earlier this year I was doing a camp fire scene at T1.5 and slog3 iso 2000 and was still struggling, but I knew this and accepted it. Cleaned up decently in post for the end film.
 
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What is recorded on FS7 cineEI is alway iso2000 so take a look at iso 2000, and in post underexpose to fight noise. Option is to setup fs7 shutter @ to 1/25 if there isn't big camera mouvements and have sony 50 @1.4. In extrême condition, there is neat video a very good video denoiser. I did a video clip named Rival(e) on my vimeo in low light condition if you want see an exemple (lenses was 25mm batis @2.0 and tamron 45mm @ 1.8 with speedbooster).
 
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Cine EI is always iso 2000, regardless of what you set the gain button to. When in Cine EI, the only thing the gain button will affect is a lut and that is just to give you a hint of what you could end up with in post. But in that case, you should set it at iso 1000 or 800, enable the lut and light to that image. As in, if 800w is not enough... move it closer or get a more powerful light. Setting the gain to fx. 3200 while in Cine will not make the camera more sensitive, since the iso is stuck at 2000. If you want to bake in a different iso you could experiment with custom and profile 7 (I think), but you would ofcourse deviate from slog.

I think your preset whitebalances has one that you can adjust when in Cine gamma... 5600k might not be the best option for night shots. Once I accidentally forgot to change the WB from 5600k to 3200k during a studio shoot and man was that mess to clean up x( so double check your WB button. Ofcourse if you are mixing the light from the night sky with tungsten sources, then 5600k might be what you want, or somewhere around 4000k to get both the blue from the sky yet not make the tungsten too warm.
 
https://www.youtube.com/watch?v=q2eV9egVnaA

shot with available light at night in kuala lumpur.
CINE EI
Slog3 Sgamut3.cine 100th/s shutter
4096x2060

Used a speedboosted 50 and 24mm 1.4 so 17mm f1.0 and 35mm f1.0

When shooting low light I usually rate the camera EI1000

But mostly its about using cinematography to convey the dark space. The problem is usually not that the camera can´t see enough its that the use of light sources dont create any depth to the space and/or definition to the the objects/character that the images should convey.
 
Shot mostly 50/60p under 50hz streetlights. For the other 24-30p shots i kept the shutter on 100 to get some edge in movement/motion
 
Amadou said:
Does that mean all I can do is open the lens aperture to its highest level and pray? ��
Click to expand...

No it means you can preplan your shoot and get the appropiate lights. Filmmaking is technically a somewhat exact science, not a "I would like this... so I want the camera to be able to do this."

Like I said earlier, if you already knew what camera, lenses and iso then you would have known what light was needed to pull it off.
 
In principle I don't really want to help you Amadou because of your attitude in earlier posts, and because you really should have done some testing before shooting at night, but its hard to watch a man drown so here are a few simple suggestions:

1- Get out of Slog. People make a fetish of it. You don't need it for night shooting and it forces you into very low ISO's and just wastes much of your available data. Choose Hypergamma 7 .
Set your lowest zebra to 60 and make sure caucasian faces don't go above the zebras as they will start get a compressed look.
2- I always use DB instead of ISO as a way of reading Gain. Though it doesn't matter I can't advise on on ISO setting. If you switch the readout to DB then you will have clean footage right up to 12DB. That might be around 3200 ISO. As I recall you should be about 1/2 stop short of the maximum gain setting allowed.
3- Open your shutter as much as can but if you have streetlight or other uncontrollable sources watch out for flickering. 1/90th or 1/100th motion blur won't look very noticeable unless you have a lot of movement and IMHO its preferable to noise.
Slight motion blur at night might look intentional anyway. TEST.

Used this way the FS7 is a very fast camera and you should have enough light in most situations.

Please don't respond with insults.


(BTW - legrevedotcom I think you meant to say Cine EI instead of cinegamma. Cinegammas in Sony "non professional" cameras are very similar to Hypergammas in the pro line.)
 
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LennyLevy said:
In principle I don't really want to help you Amadou because of your attitude in earlier posts, and because you really should have done some testing before shooting at night, but its hard to watch a man drown so here are a few simple suggestions:

1- Get out of Slog. People make a fetish of it. You don't need it for night shooting and it forces you into very low ISO's and just wastes much of your available data. Choose Hypergamma 7 .
Click to expand...


STD Gamma works well at night too.
 
I often use standard gamma but the knee circuits can distort overexposed colors in a nasty way , and since that's quite likely at night where light sources are visible I would generally avoid it. Depends on the content of your shot of course.
I only suggest HG7 because its the closest to log but any hypergamma would work as well as Std as long as the hot areas are controlled. HG7 seems to raise the gamma point so the image is brighter, hence it seems better in low light. and needs less apparent gain. That may increase noise though, i've never tested carefully.
 
There is not enough information to answer the question. What in the image are you expecting to reach 70%?
What kind of 800w light?
How far is the light from the subject?
Show us a snapshot and discuss.
 
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LennyLevy said:
I often use standard gamma but the knee circuits can distort overexposed colors in a nasty way
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For that very reason I spent quite a bit of time trying to get the best results out of the knee circuit. I decided to have a go at this after I noticed very early in the piece where under certain conditions you will see the WFM pump as you pan across certain subject matter. First noticed the WFM pumping when panning from a white building in the sun to the shady side of the building and was surprised to see the waveform levels alter. Almost like a small auto iris movement. Another situation that caused the pumping was strobe lights. The pumping is the auto knee trying to compensate for the rapid changes in highlight levels. Not a nice look. Strobe lights in a night club shoot caused a lot of pumping highlights under the auto knee. After a couple of days of experimentation in studio and outdoor wide dynamic range situations I came up with a manual setting that seems to work for me and that handles most highlight extremes pretty well in standard Rec 709 modes. It avoids using the auto knee which can introduces some of those funky colors that LL mentions. When exposing for average max peaks at around 95 IRE in 709 mode I find these settings give me the smoothest compression and roll off of the knee with the White Clip set to 105.

Auto Knee OFF
Manual Knee is on with
Point @ 85
Slope @ +40
Knee Sat is ON
Knee Sat Level @ +15

In set studio or fully controlled lighting conditions where I can control the dynamic range of the lighting then as is normal broadcast studio set up practice I turn the knee off and light accordingly so that your extreme peaks don't go high enough to require a knee. Therefore any compression of highlights is avoided.

Chris Young
 
NEVER USE AUTO KNEE for that reason.

Knee is a very tricky circuit. Back in the Neanderthal days we used to ride with a video tech who painted every shot and a good tech would adjust the knee for each one. I set mine conservatively with a point at 92 and I think the slope is 50 or whatever is the midpoint ( is that 0?) I don't screw with the sat at all. If it impinges on important info , esp a face it can look awful and 85 sounds a little aggressive to me. Yours might be a good general setting but I dont want to have to adjust it for each shot so if the material has hot spots I just switch to HG which always reads them cleanly.

Haha I don't think the OP is looking at this at all anymore.
 
Slog 2 or 3 custom.

Yep people will say the colours are 5% wonk.. but that is the least of the problems in the super dark.

not super dark? slog as per usual.
 
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