Auto Facial Focus vs Manual?

[Todd Terry]

Not to try to sound smug or all high-and-mighty, but a “real” cinematographer would rarely if ever use auto anything. Most high-end cine cameras don’t even have any auto modes at all… you have to do everything manually, and it definitely gets the best results.

Your case is a perfect example of how auto functions are just causing you problems.

Some auto functions can be useful in, say, documentary or run-n-gun situations where you don’t really have much choice… but in a completely controlled situation like an interview there’s no reason to use them at all.

Focus manually, and expose manually. I’m betting you have your subject on a dark or limbo background and thus your camera is overexposing, probably by jacking up the gain (depending on which auto setting you have on), which is introducing the noise.

Shooting manual will fix that. Best to have a good monitor as well so you can really see what you are doing.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com

[Patrick Bronte]

Hi Todd,

Thanks for that. You didn’t sound smug to me. I’m a complete novice so tapping into the experience from pro’s like yourself is the reason for joining the forums. I’ve only ever done things on a hobby type level but now I need to learn these things to step things up to the next level.

You are correct about the black screen background and the reasons you’ve given for the over exposer sounds .

I have one little obstacle in my way though. I’m just an interviewer and due to paralysis I can’t physically adjust the settings while the interview is taking place. I have help to set everything up (lights, screen and could do things like manual focus just for an example) and push record but they have less understanding of operating the camera than I do. But as long as I can figure out and learn exactly how to set things up manually I can then instruct them.

In most cases I can get the talent into a controlled room where nothing changes (such as lighting & position) from start to finish but there are going to be situations where I will have to go to the talents residents and won’t have that same control. I’ll still use the screen and lights but my concern is being able to totally block off all the natural light.

So in my case of recording talking heads, If I manually set everything up, what camera functions (gain, exposer etc) would need the most monitoring and be changed throughout the course of the interview? What would be the most crucial things I need to look for? I tend to use auto functions so I can set and forget and not have another person sitting in for the people I interview don’t respond as well with an audience but I can’t have it all. Can you please suggest the most important functions to set up manually and any advice on how to get the best results considering my circumstances?

Thanks again Todd!

Kind Regards,

Pat

[Todd Terry]

Well Pat, I think your lighting situation is more controllable than you think. When you are lucky enough to be shooting on stage in your fully-controllable studio setting there is no real forseeable reason to ever have to fidget with the exposure once you have set it correctly for a particular interviewee. I mean, it could happen (maybe you’re using a close softbox as a key and the talent decides in mid-sentence to move two feet closer to the instrument… or you have a bulb blow in a fixture), but usually that’s going to be a “set it and forget it” type of situation. If it looks perfect when you set it, it should hold throughout the interview.

The same is true for most of your location interviews, even if you can’t block out all the ambient light. Lighting is typically not going to change enough that that’s much of a real concern. It could be, if interviews were hours long so that changing exterior lighting becomes a factor, or you have a lot of natural window light that keeps shifting from cloudy to full sunlight… but it doesn’t sound like that’s your situation. Again, if it looks perfect when you start, it should look pretty much like that when you finish your interview.

I was anti-auto-anything in my previous answer to you… but in light of your physical challenges this might be a case when auto focus works well for you… if you are shooting with longer lenses or a wide-open iris you might get a depth of field shallow enough that an interviewee leaning forward or backward even just a bit gives you a soft image. If you or an assistant can’t manually pull focus to keep your subject’s eyeballs razor sharp, then this might be a case when I’d break my “no auto” rule and try autofocus. That’s not what was causing your previous problems of exposure and noise, though.

Those were caused by two things… the camera interpreting what it saw as proper exposure incorrectly, and high gain.

Your black background is playing hell with the autoexposure, and overexposing the talent. This can be fixed with going full manual on exposure. If you must rely on autoexposure, most cameras have a +/- adjustment that will tweak what the camera senses as “correct” up or down. You can use this to refine your autoexposure and get your talent looking good.

The video noise you see (which will be more evident over black) is likely being caused by your gain being too high… which in turn is caused by your auto exposure mode set to what is probably not the best choice. If the camera senses there is not enough light, it is going to do one of three things (or a combination of these): It will either open the lens iris more, or it will slow the shutter speed, or it will increase the gain. It all depends on the auto mode you have selected. An “aperture priority” mode, for example, fixes your f/stop at whatever you have selected and adjusts shutter and gain to compensate. A “shutter priority” mode fixes the shutter speed and adjusts the iris and gain instead. If you must auto expose, you need to be careful about which thing the camera is adjusting. You generally don’t want it to mess with your shutter speed… a “normal” shutter is one over twice the frame rate (ergo, for 24p the normal speed is 1/48th of a second). Faster or slower than that and you get problems. You also don’t want it to jack up your gain or you can get video noise. In your situation, ideally you’d like to lock the shutter speed and the gain and allow the camera to auto expose only by opening and closing the lens iris. No doubt your camera can do this (most can), but I can’t tell you specifically how to make these settings. This will be one of those times to actually dig out the camera manual.

Good luck… I don’t think you will find this all that hard once you figure out how to do it the first time… all the rest will be easy.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com

[Patrick Bronte]

Cheers Todd! Thank you for all that food for thought! I’m studying the manual as we speak. I use the Canon XF-100 and once I find out more about exactly how to manually make these adjustments and how to customise the auto settings I’ll get back to you if that’s o.k.?

You mentioned cloudy days and long interviews on location. Well sometimes these oral histories can go for up to 4-5 hours so there are changes in the lighting as the sun goes down or clouds pass over. I’ve invested in a good fluro key light with a soft box and head light to overcome the slight changes that can sometime be seen on the screen.

You mentioned a good monitor. I usually just flip the cameras lcd screen around and watch that. Can you tell me if the monitor I’ve linked in here would be a good start? I’m low on funds but if you could recommend something that would have the flexibility to be mounted on my wheelchair would be much much appreciated.

As a side note: if I’ve got the Zebra function on and there are no “lines” appearing on the skin on the talent am I on the right track exposer wise?

https://www.bhphotovideo.com/c/product/843442-REG/INDIPRO_TOOLS_CORP_PRO5_LCD_LPE6_PRO5_LCD_KIT_w_CANON.html

[Patrick Bronte]

Todd,

If I really have to use auto mode which modes would you say I could get away with? Could I get away with auto gain for example? Would it be to much trouble for you to list by priority which manual settings I should be using (i.e 1. focus, 2. shutter speed etc) for my situation in a studio setting and on location. Then I can prioritise the functions and make better sense of the auto functions.

Your help is really shinning a light on things. Thank you very much!

[Patrick Bronte]

When using artificial lighting would you turn the gain off or have it on low?

[Todd Terry]

Hey Patrick if you can give me a little more time when I’m in the studio sometime I can download your camera manual and maybe give you some more specific how-to advice, but for now some quick comments…

Ok, first, wow, I didn’t know you were talking about interviews that were hours long. Yes, you might certainly have to make exposure adjustments as well as focus and framing adjustments periodically. I’m sure no one is sitting there for a continuous stretch that long… so you have to break that up and maybe sort of think about it as “scenes”… even though they all look the same. Any time there is a change… the lighting changes, someone moves, you all decide on a bathroom break, the talent needs to get a drink, whatever… think of that as a scene, and every scene will probably have to have focus, framing and exposure adjusted. I don’t think there is much way around that.

The little flip screens on most cameras are ok for exposure and framing, but most are not good for focus… the resolution is just too low. Something might look razor sharp in them, but in actuality when viewed at full 1080 an image can be soft. That’s the same problem with the little monitor you linked to… that size would be very convenient to mount on your chair, but its resolution is quite low. Look at the technical specs, it’s only 480 lines… so again something could look sharp on it but it actually quite soft on the big screen. There is a cheaper/better route, but might not be as convenient. For something in the neighborhood of 100 bucks you can pick up a small monitor in the TV department of Best Buy, Target, HHGregg, or any store like that, that will be at least 720 lines and good enough for focusing. Unfortunately though those are still going to be physically at least twice the size or more of the little IndiPRO monitor, so it might be harder to mount conveniently to your wheelchair, if not impossible. The little monitors from SmallHD are true HD monitors and would be convenient for your to mount and use (and run on battery power), but they are going to be twice the price of the one you linked to, or more… although they do crop up on eBay now and then for good prices. This one is going to be a juggling act of how much you want to spend vs. what works well. Not a real easy and obvious solution.

The zebra function might be useful depending on how controllable the settings are on your particular camera. If the zebras are permanently set at 100% or 90% or whatever, then no, they are not useful. But if your camera will let you custom set the zebra level at something lower (like about 70%) then it might be helpful. Personally I never use zebras at all.

You asked “Could I get away with auto gain?” Noooo. In your case gain is the LAST thing you’d want to auto. That’s what is causing your noise. Always shoot in a mode where gain is manual. As for turning the gain up, with your black background (which will have a tendency to show noise) I’d personally never jack the gain up at all, unless I really had to.

As for priorities, you’ll be wanting an auto mode that only adjusts the iris, and locks the gain and shutter speed. I’ll try to look at your manual when I get an opportunity and see if I can give some better advice… it might take me a day or two to get to that though.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com

[Craig Alan]

A few thoughts.

Use as little gain as you can.

If you can afford a couple of kino diva lite kits go for it.

Get them with both studio temp and daylight temp bulbs.

Make sure your zebra stripes are set to 70-80 ire not 100.

Then you want to see a few zebras appearing on your subject’s face-the highlights such as cheek bones and tip of nose. Play with the exposure control-have the zebras fill the image (over exposed) and then none (under exposed). You’ll get the point of these built in light meters. 100 IRE is overexposed. You can use this setting to look for hot spots in your image.

When you say head light I assume you mean back light?

If you are shooting outdoors find a well shaded area or wait for the beginning of sunset.

Or set up a tented area or use a large butterfly.

If you are using a black (or any color) background – move your subject as far from your background as
possible. Move you camera as far from your subject as possible. Zoom all the way into your subject’s eyes and focus manually. White balance manually on a white card where your subject’s eyes will be. Zoom out to your framed shot. Then, adjust the exposure manually.

Look for the catch in your subject’s eyes from your key light. One white dot per eye.

Move your fill light so you don’t add snake eyes (two dots in your subject’s eyes).

Make sure your backlight is creating a nice glow to your subject’s hair. This will help separate your subject from your back ground.

Get some b roll footage such as close ups on things your subject talks about. You can not only tell a better story this way but also edit out shots when your subject moves out of focus or out of frame.

Ideally in a studio you’d have a broadcast monitor. If this is too expensive then a panasonic plasma can be a decent substitute.

https://www.shopfsi.com/

https://www.bhphotovideo.com/c/product/780138-REG/Panasonic_TH_42PH30U_TH_42PH30U_42_Class_HD.html

I have not seen a good monitor for $200-$300 but maybe some are better than the built in LCD.

With an external monitor you can turn it toward the person adjusting the lights so they can see what the image looks like.

Mac Pro, macbook pro, Imacs (i7); Camcorders: Panasonic AG-HPX170/AG-HPX250P, Canon HV30/40, Sony Z7U, VX2000, PD170; FCP 6 certified; write professionally for a variety of media; teach video production in L.A.

[Patrick Bronte]

Todd you are a legend! Thanks for all your advice and help.

Believe it or not but my interviews can go for up to 5 hours. I interview war veterans so theres a lot to talk about. I’ve only ever used consumer grade cameras where there aren’t really any manual settings. But now it’s time to go prosumer and get a better recording that I can use for a doco of something down the line.

As for a monitor – I think if I’m going to do this properly then stuff it I’ll pay for an HD monitor with at least 720 lines. If I can’t find one to mount to my chair or camera then I’ll find a stand or something.

Your offer at looking through the XF-100 manual to help me with all these issues is really appreciated! Here’s a link to a pdf download:

https://support-sg.canon-asia.com/contents/SG/EN/0300450301.html

Now I’m going to have a good play around with the manual settings taking into account all of your advice.

I look forward to hearing back from you.

[Patrick Bronte]

Cheers Craig! Thats some good advice. So with the zebra – do you want the lines to appear on the talents face? I thought the lines meant that there was over exposure. I must read up on that.

Thanks again. If you have any more advice please let me have it!