Is my exposure off? Noisy FX9 in SLOG3

S

seanadl

Active member
Hi all,
I'm experimenting with using SLOG3 to record in. Using a Rec709 lot to monitor I thought I had set the exposure correctly in camera (at least for the face). However, looking at the footage in the edit, it's really noisy. I know log can be quite noisy, but this seems a bit excessively so.

The set is quite dark (lots of black surfaces) - so wondering if this is causing the noise problem to be highlighted. Attaching a still taken from Resolve: https://www.dropbox.com/s/49pu2i0ix0sdg7t/Untitled_1.1.1.tif?dl=0
 
seanadl said:
Hi all,
I'm experimenting with using SLOG3 to record in. Using a Rec709 lot to monitor I thought I had set the exposure correctly in camera (at least for the face). However, looking at the footage in the edit, it's really noisy. I know log can be quite noisy, but this seems a bit excessively so.

The set is quite dark (lots of black surfaces) - so wondering if this is causing the noise problem to be highlighted. Attaching a still taken from Resolve: https://www.dropbox.com/s/49pu2i0ix0...1.1.1.tif?dl=0
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I think it is hard to tell how noisey something is from a still image, but it isn’t that bad. Looks like you have a few options to improve it. but overall very usable footage.

lighting is all about ratios, so you start changing one thing and it effects everything else. :)

- definitely doesn’t look over exposed, you could expose a bit brighter
- add more fill or ambient light. even if you like your key light, sometimes a little help with a bit of soft ambient light (from above usually is natural) can help clean things up
- Sometimes blue can show more noise than other colors. not sure if you should add more light in the blue area, introduce a bit of white light there, or just open up your exposure?
- is that a tv screen behind the main person talking? it looks a bit brighter than the speaker. you could balance out the ratio a bit more, by giving the talent more light or dimming down the tv screen

There are other people that will have a ton of advice coming soon. They’ll have pretty strong opinions. Should all be useful info.


It will help if you can give a few more technical details.

wish you all the best!
 
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JimGao said:
I think it is hard to tell how noisey something is from a still image, but it isn’t that bad. Looks like you have a few options to improve it. but overall very usable footage.

- definitely doesn’t look over exposed, you could expose a bit brighter
- add more fill or ambient light. even if you like your key light, sometimes a little help with a bit of soft ambient light (from above usually is natural) can help clean things up
- Sometimes blue can show more noise than other colors. not sure if you should add more light in the blue area, introduce a bit of white light there, or just open up your exposure?
- is that a tv screen behind the main person talking? it looks a bit brighter than the speaker. you could balance out the ratio a bit more, by giving the talent more light or dimming down the tv screen

There are other people that will have a ton of advice coming soon. They’ll have pretty strong opinions. Should all be useful info.


It will help if you can give a fee more technical details.

wish you all the best!
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Thanks for the advice! Really appreciate it! Yep, the image is harder to see the noise on than when looking at the moving pictures. It definitely needs NR for it to look in any way decent .

I'll try exposing a bit brighter and adding some fill to lift things up a bit. I still want the blacks to look black, but perhaps lighting them up and then pulling it down in post will clean up the noise?

Re: the background TV. That proved to be annoying. I usually film 30fps with a baked in Rec709 look. This time I wanted to film 25fps, SLOG3 (UHD, 5k crop). As soon as I did that, the TV was flickering like crazy in the background. The only fix I could find in the time I had was to increase the backlight of the TV a bit. The TV is supposed to be one designed for filming and displays - it's not a standard consumer TV - so that's another issue I need to troubleshoot some more.

Some technical info:

Shot on FX9 in Slog3. 25fps, 5k crop, UHD. Aperture at 4. 180 degree shutter. EI set at 1000. Using two main light sources in front of the host (Nova P300's with softboxes attached set 5600k). The set is backlit, and the TV screen behind the host is built into the set.
 
Re: tv, sometimes a higher refresh rate on the tv can help with flicker too. Something 120hz or higher. but yeah, getting all the frame rates to match can be ideal.
 
seanadl said:
I'll try exposing a bit brighter and adding some fill to lift things up a bit. I still want the blacks to look black, but perhaps lighting them up and then pulling it down in post will clean up the noise?
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ideally you wouldn’t have to do anything in post after you get things the way you like them on set. Given this looks like a studio setup you can use a lot. If you were just shooting it one time, maybe doing post work would be worth it.

That said, you could rate the camera for iso 800 or even 640, and then add light on set. That will also help clean things up.


seanadl said:
Some technical info:

Shot on FX9 in Slog3. 25fps, 5k crop, UHD. Aperture at 4. 180 degree shutter. EI set at 1000. Using two main light sources in front of the host (Nova P300's with softboxes attached set 5600k). The set is backlit, and the TV screen behind the host is built into the set.
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I’d probably use 5K crop too, just to get a little more dof, but if you are trying to avoid noise, a crop in can show the noise as bigger. This is only an issue if you are under exposed though. So once you get things sorted you shouldn’t have to worry about it.

Also, what is your ire for black? black doesn’t have to be 0% or 1% to look black. you can be higher up the scale depending on the picture profile. If you use S-Cinetone for a LUT, then your black level is a bit more crushed (1.5%?) and you may even want to bring it back up. Haha.
 
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Are you rating the camera at EI 1000 in the Base800 mode? If so then you’re technically underexposing giving more priority to the highlights and taking away from the shadows which can lead to noisier images. It is important to know that EI is not the same thing as Gain so it wont be like when you are filming in Rec709. In CineEI on the FX9 your sensor’s sensitivity is locked at Base 800 or Base 4000. There is no additional gain applied to the sensor when changing the EI, it is just the MLUT that changes to trick you into exposing brighter or darker. Using an EI that is higher than the base sensitivity means you would be underexposing to make room to capture more information in the highlights at the expense of shadow information and using an EI lower than the base means you would be over exposing to make room to capture more information in the shadows at the expense of highlight information.

Maybe flip to Base4000 and rate the camera for EI 2000 or 1000 (equivalent to overexposing by one or two stops respectively and lifting the darkest areas out of the noose floor) to give more priority to the shadow areas and lower the exposure in post. See if that is satisfactory for your needs. One thing to look out for is clipping an individual color channel when you do this, for example the red channel of your subjects skintone.

If you are filming in an NTSC country just use the correct shutter speed for the mains frequency ie 1/60 so the tv doesn’t flicker. Maybe go back to 30fps. I personally dont see any benefit to filming in 25fps if you are NTSC based and dont have to integrate with a PAL production.
 
Sean , First You haven't asked answered the question as to whether you were using EI 1000 on high base or low base. That's very important re noise. Secondly , you said you used a LUT to determine exposure, but not how you decided on your level. Did you use zebras or waveform ? If not you are just guessing based on how your monitor or EVF happens to be set up which is very dicey. I tend to to rely on my zebras at 60% when dealing with caucasian faces and a little lower otherwise. To me it looks like your shot is underexposed something you never want to do in SLog . I don't think you need more fill light just more f stop and some backlight wouldn't hurt . The background looks difficult if that's all a screen because some is very dark and the TV image is too bright . I'd try to balance that if you could.
 
Lenny, good post. The root of the problem is that some people don't understand that exposure and lighting are two entirely different things that have virtually nothing to do with each other. Until people can wrap their heads around that they will just be chasing their tail. Lots of irrelevant technical data has been posted, but no meaningful details about exposure methods or target levels. Also no information about what country this is being shot in. If someone doesn't understand why that is relevant, then they are really in the dark. There are so many red flags in this thread that show the most basic stuff about shooting isn't understood. It would be hard to offer any meaningful advice becuause there is so much material that would have to be covered.

This setup is in a studio with 100% control over the lighting and exposure. There should be no noise issues whatsoever.

Half-assed advice about black levels and crop modes just compounds the problem and makes things even murkier.
 
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One more thing I forgot to mention -- why the hell is S-LOG3 even being used in a setup like this? This is exactly what S-Cinetone was designed for and it is so much simpler to use for people who don't have the skills for S-LOG. And if someone doesn't ike S-Cinetone, there are literally hundreds of REC709 paint menu choices available to dial in a nice WYSIWYG look that will meet or exceed whatever could be accomplished with S-LOG in the studio.
 
morgan_moore said:
.. exactly because these are hundreds of choices?
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I actually like you advice earlier. I’m assuming the bump is generally the subject, and in a lot of cases, the subject is exposed right around or above the middle IRE percentage.

I might try to avoid a down curve or any curves adjust just to stick with more industry standard values.

It should be a t-shirt, but it could be taken the wrong way.
 
Doug Jensen said:
One more thing I forgot to mention -- why the hell is S-LOG3 even being used in a setup like this? This is exactly what S-Cinetone was designed for and it is so much simpler to use for people who don't have the skills for S-LOG. And if someone doesn't ike S-Cinetone, there are literally hundreds of REC709 paint menu choices available to dial in a nice WYSIWYG look that will meet or exceed whatever could be accomplished with S-LOG in the studio.
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I agree completely . In a studio unless you are planning to match disparate cameras why the hell bother with Slog. Make your choices on the set. Its not wrong but please understand it first. I confess I don't set my exposure the same way you do - but we are both using a waveform and using it intelligently. Without tools you are wandering in the dark.
 
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LennyLevy said:
I agree completely . In a studio unless you are planning to match disparate cameras why the hell bother with Slog. Make your choices on the set. Its not wrong but please understand it first.
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when starting out, might as well use Slog, and then dial in as you go. Also, applying a LUT is fairly easy these days. But at the end of the day, once you have things dialed in, shooting directly to a picture profile is more effecient, even if it is just a dropdown menu away.
 
Hi all,

Sorry for responding late! I have to admit, I'm still very much learning. I'm not a camera person by trade - this project is just me and my husband, running a small studio and uploading what we hope are professional looking produced videos online. I produce, write, direct and host the show myself.

My background is in television production- I worked in the UK television industry for 20 years - first as a runner then all the way up to producer. The only time i've had to film anything on a camera myself was back when I was an intern at MTV. They'd give you a PD150, and as long as you could switch it on it wasn't too shakey - your footage would be ok to go. So that's the extent of my camera training.

To answer some questions... I'm based in the UK. The camera is in base 800 mode.

I wanted to try SLOG primarily to learn more about the camera and see what type of picture I can get out of it. The painT menus are DAUNTING to say the least. But I can understand why dialling in a Rec709 look in camera would be much more preferable in this situation than filming in LOG. I think i'll get there in the end.
 
Hi seanadl,

Thanks for the additional information. I think I can offer some advice that you may find helpful. This assumes the camera is basically on the default settings and there isn't a lot of stuff that has to be undone.

First, forget about S-LOG. It is over your head right now and there will be plenty of time to play around with it after you have already mastered other aspects of the FX9. As they say, learn to walk before you run.

Second, set your camera for S-Cinetone and you'll automatically be 90% of the way to a nice look right out of the camera with no heavy grading in post and no messing around with the other paint menus or dialing-in someone else's scene file. No LUTs to fart around with either. Again, you can explore the paint menus later when you have more experience under your belt.

Third, you say you already set the camera for 25P, and that is a good choice because you are in the UK. And 180 degree shutter is also a good choice. Keep those settings.

Bonus: If the screen on the monitor in the background is flickering or rolling, change the Shutter speed mode to ECS and then adjust the ECS Frequency until the screen looks normal.

Fourth, go into the menus and make sure the camera is set to show GAIN rather than ISO. Put the Gain switch on LOW and and then verify the Gain is on 0db. if not, change it in the menus.

Fifth, go into the menus and turn off Zebra1 and turn on Zebra2. Set the value of Zebra2 at 85.

Sixth, have your talent sit in position and adjust the composition and blocking exactly how you want it.

Seventh, get your key light and fill light roughed-in so you are getting the the look you want, but don't worry about exposure yet.

Eighth, if you want a shallow DoF look, then open your lens to the widest aperture. If you want the background to be a little more in focus, then choose the f-stop that gives you the creative look that you want. You should always choose your f-stop creatively rather than having your hand forced by the intensity of the lighting.

Ninth, have the talent hold a white card in front of their face while you adjust the dimmer on the key light so there is just a touch of zebra on the card. Depending on the power and placement of your lights, speed of your lens, and other parameters, you may find it useful to turn on the Variable ND of the FX9 and use it to adjust the exposure up or down until you see just a touch of zebra on the white card. I almost always have the ND turned on for an interview or a headshot like this. It just gives you so much more leeway when you start dimming the lights to get the look you want.

Tenth, once the key light it set and the exposure is set, now adjust the rest of your lights (backlight, kicker, fill) to get the look you want on the talent. You may have to double-check the exposure again and make adjustments as you change the lighting, it depends on how flat you are going with the key/fill ratio. BTW, in the image you posted earllier you really, really, need add a good backlight directly behind the talent's head and above the frame. It would make all the difference.

Eleventh, now that the lighting is done, put the white balance switch on Memory A. Aim the camera at a white card being held where the talent will sit,and fill the viewfinder with the card. You may have to zoom in or physically move the camera closer and then put it back at the original location when you are done. You may have to iris-down the lens to a darker exposure in order to get a good white balance. No problem, just remember where you had the iris and put it back again when you are with the next step. Press the WB Set button to set the white balance so it matches the color temperature and tint of you lighting. Put the camera back into position.

That's it. Now you are ready to shoot after you have setup and adjusted your audio settings.

In post, you may want to fine-tine the look of S-Cinetone, but that can be done with the color tools in your NLE. Unlike S-LOG you will not need to run the footage through Resolve.

I hope that helps.
 
Very Very good advice. I use the zebras differently . I set one at 100 and the other at 60 aiming to make sure some of the 60 zebra is on a caucasian face but that takes some finessing to know how to adjust fro someone who isn't caucasian because 60 IRE may be too bright for them . That's particularly valuable if you're in a situation where you can't be running a round with a white card or your following action that is changing . However Doug's method is very accurate. Absolutely follow his advice about using "gain" instead of ISO. Otherwise you ned to know what the ISO's are for every gamma and that will drive you nuts and lead to mistakes.

Your backlight doesn't need to be directly behind , it can also be from the side or from both sides which I prefer but you usually need backlight for separation especially for someone with dark hair.

Incidently you did underexpose the Slog a bit by rating it at 1000 on base 800 and then you further underexposed the shot itself by not using a waveform to get his face bright enough. That's why its noisy . After adjusting your exposure in post ( get his face up to around 60-65 IRE) then you can get rid of the noise with a plug-in called "NEAT Video" that does wonders with noise. I think its around $100 now for most editing systems .
 
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seanadl said:
Hi all,

Sorry for responding late!
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No worries.


seanadl said:
I have to admit, I'm still very much learning. I'm not a camera person by trade - this project is just me and my husband, running a small studio and uploading what we hope are professional looking produced videos online. I produce, write, direct and host the show myself.

My background is in television production- I worked in the UK television industry for 20 years - first as a runner then all the way up to producer. The only time i've had to film anything on a camera myself was back when I was an intern at MTV. They'd give you a PD150, and as long as you could switch it on it wasn't too shakey - your footage would be ok to go. So that's the extent of my camera training.
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I was just talking about the Sony PD150 on another thread! An iconic camera.

The experience you have shows as the core elements of the the setup is good, and you have world class tools to work with. What puts you in a unique situation is the possibility of reaching out to a colleague or a friend of the friend in the industry that you respect, and hire them for an afternoon to improve things. That one day of paying can save money in the long run. Morgan Moore said it well in their second post: so many variables
 
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LennyLevy said:
Your backlight doesn't need to be directly behind , it can also be from the side or from both sides which I prefer but you usually need backlight for separation especially for someone with dark hair.
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Sometimes maybe, but if she's going for the traditional in-studio network anchor look, the key and fill need to be almost the same and the back light needs to be exactly the same on both shoulders. That can only be accomplished if the light is hung straight behind the head. A light from the side, or one from each side, would be a kicker(s), which is optional in this case. The back light, though, is mandatory and sorely missing in the posted example.

If he is NOT going to be evenly lit on both sides of the face (recommended) the brighter key side should be the side that has the monitor over his shoulder. In the posted example he is brighter on the wrong side.

Finally, the desk that he is resting his arms on is a little too high, which gives him a slumped look. Lower the desk or raise the chair.
 
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