Setting exposure, I need another lesson
 

Sometimes I struggle getting the exposure that I have in my mind and also from what the camera is telling me and it's when I get back into FCP that I see all my good work and not so good exposure show through.

I'm really only talking about skin tones here but this could and does apply to all scenes.
I have my zebras set at 90% for skin and 100% for everything else's and if I see 90% zebras on skin I back off until they are gone. Now when I'm on a shoot skin tones are the major priority if this is my main frame and focus and I shoot in all weather conditions doing talking heads stuff, interviews and the like.

I'm losing track of what I'm trying to say.
I think I would like to hear from others how they expose for skin tones both indoor and outdoors.

Thanks

I never expose for skin tones because there is too much variation between between different people. Maybe in Australia everyone looks the same, but not in the USA. Go out in public and look at the range of skin tones you'll see among any group of people. How could one zebra setting possibly cover that range of skin tones? It can't. Zebras are only useful if you know the reflectance value of WHAT you are measuring.

White objects and/or a standard 18% gray card are the only two portable and reliable sources for an ENG/EFP shooter.

I use my Zebras set at 95% and look for something white. If I don't see a little bit of zebra in the whites (not alway -- you have to use your brain!) then the shot is underexposed. Works for me 99.9% of the time. 95% zebra works for me, but it might not work for someone with a different camera setup, so don't use that number as gospel.

Anyway, even those people who do use zebra on faces wll tell you that the numbers you're using are way too high. 70% is the more standard number for skintones. I'm sure some of those guys will be flaming away in a minute to tell you how wrong I am, and that they have used zebras for 50 years to set proper exposure on skin tones. But I still contend using zebras on skin tones is wrong because skin tones ranges from John McCain to Barack Obama. Will 70% work for both skintones? Nope. But I can guarantee you that 95% will work for both of their white shirts.

The 70% benchmark for zebras may have come straight out of japanese thinking and can probably be trusted on 99.9% of japanese faces. In a more diversified environment, using zebras based on an "ideal" skin tone level just does not work. You got to look at other various factors. Like Doug, I tend to use zebras just to check my whites peaks. I also put a lots of trust in my viewfinder and keep it calibrated at all time. In a ballpark, there are basically two different situations:

- Your set is properly and evenly lit (studio, sit down interview,...): You ride your level as high as possible without overexposing skin tones. (look for those flat round spots on the chins or forehead)

- Your are in an uncontrolled setting with changing light conditions like shooting outdoors on a sunny day and on the move: In that case, you will most likely have to walk a fine line between over-exposing your skin tones a bit and keeping the overall exposure in balance. A 700 or F800 will perform better than a 350 in those conditions and will be more forgiving.

I think the one rule I would keep in mind is that if you are unsure, it is safer to stay under-exposed than going over. All post-production tools do a much better job in correcting under-exposure than over-exposure.

Thierry.

What OS are you using and how are you monitoring? Have you set up the Mac's gamma correctly. Apple's standard gamma under leopard will give incorrect mid tones on the computers display. You really need an external monitor on a decklink or AJA card.

Good advice guys, seems like I'm doing what you are doing.
I know 90% zebras are to high for some but I use this as a bench mark between, over exposing skin and someone wearing a whit shirt in direct sunlight which happens most of the time.

I'm monitoring on a computer screen and also going out to a broadcast monitor via firewire and using FCP 6.06 on a MBP. What gamma settings should i look at changing to?

Thanks

I use both zebras, the one set for 100%, the other for between 85-90%. For skin tones, I'd then expose so that normally I'm only getting the latter showing on highlights within the skin tones - the bulk of the face sitting well below the band - and I find this works well for all racial groups and skin colours.

There are two problems with the 70% idea. Firstly, (as already said) skin tones vary from person to person. But even if you do get a 70% "standard" person, it relies on zebraing across the whole face and that makes appreciating the image through it far more difficult. The method I'm suggesting above avoids that - most of the detail in the image is below the active band.

I do recommend trying both patterns together, they're very easy to tell apart and you shouldn't normally get too much of the 100% zebra anyway. But it can be useful to know exactly when some detail is peak white.

My problem...

is that if using zebra a lot (Zebra 1 +2) + VF peaking the picture of the viewfinder gets more and more "crowded".

Meanwhile I use LESS peaking (for a better picture quality in the VF) and only one "warning" zebra at 95 or 100 (depending on the job).

for any tripod situation (no run & gun) I use a 9" lcd monitor + waveform, and this is one of the best ways to judge about sharpness AND exposure...

Uli

70% zebra is typically for Caucasian skin tones. Darker skinned people typically run about 55% but it's not a hard and fast rule.

That's why zebras are a guide. Everyone says how different skin tones are at different levels. Well yeah, they are. Buy you are going to be closer to that guide for exposure using 70% zebras than 100% ones! At least with 70% zebras (or 60% when using cine or hypergammas) You can calculate the variation more easily.

I always use both 100% and 70%. 100% on their own are useless. What good is a sky with no overblown highlights if the foreground is the focus of your shot and is under exposed?!

Since I switch back and forth between camera brands and models I have to set zebras based on different cameras capabilities. Also different displays handle exposures differently so it is difficult to set one standard for settings. Sony lets you display two kinds of Zebra with a slice which makes them disappear after the signal goes out of the range while Panasonic just lets them appear making it difficult to see when the higher setting really is coming in.

I set my zebras on 80% and those show just a little on highlights. This is a general rule.
If the subject is dark skinned I think I overexpose a little and try to get more of a backlight/kicker and again in those areas I try to get those 80%. On outside scenes just try
to evaluate your contrast and judge before setting exposure. I also always look for a darker background if possible.
If we talk about zone system you could decide what is your 18% grey as it would be your zone 5 and work the rest from there.

The purpose of zebras is to take the guess work out of setting the exposure.
If you're using zebras, and still find yourself frequently "guessing" as to what the exposure really ought to be, then I'd say you're not using zebras properly. I can guess at the exposure too, and I don't even need zebras to do it! I trust my zebras and really think twice before going against what they are telling me.

I make absolutely no adjustments for differences in skintone, because I'm not metering someone's face. It's an unknown, variable value, and therefore tells me nothing about what the exposure should be. Give me an 18% gray card or something white in the frame, and now I know exactly how that should look because it is a known value.

Hi Doug,
I have a Z7, a S270 and a F350 and what I do not understand is that Sony has not included a histogram in the most expensive cam of the three, the F350. I'm used to histograms from my profession (stills photographer), and on the video side I also find it very handy to get a one-glance idea of the total exposure. Of course zebras are excellent, but having a histogram as an extra aid is even better. Just my 2 cents, as a video amateur, of course.

I learned a lot from your instruction DVD's, by the way!

Hi Luc,

I'm glad to hear that my DVDs have been helpful to you.

You are not alone in your opinon of histograms. I hear a lot of experienced still photographers say they miss having a histogram as they move up to high-end video cameras. But if you really give zebras a chance I think you'll discover that, when used properly, they can be so much more useful than a simple histogram. The information a histogram displays is just too crude when compared with the precision of zebras. When I'm shooting with my Nikons, I miss having zebras!

I think if you took a survey of expereinced professional video shooters, hardly any of them would want or use histograms cluttering up valuable viewfinder space -- thus Sony does not provide them. Of course having a choice is always good, so I agree, having histograms as an option would be best.

Doug, this is probably a very silly question, but how do you go about when filming a subject with very little contrast, such as a panoramic view of the sea with no (darker) nearby objects? I don't see a way to use zebra there as the contrast is so low.