Thanks Spot - that's what I needed to know.

So use 70 for shooting interviews. Would you recommend using 100 if working outdoors (landscape footage, etc)?

Cliff Etzel - Solo Video Journalist
bluprojekt | solo video journalism blog

I never use 70, i always use 100. 70 is to check that you have more or less proper exposure. Lets say your zebras are at 100 and you don't see it anywhere in your image so you might think that your images is underexposes so when you turn zebras at 70 and see little bit of those on the faces of your subject then you can be sure that your exposure is right on the money.

That said though all my cameras are always set with zebras at 100. HDV and HD in general makes it a bit problematic because even some areas with zebras at 100 still retain some color information and on top of that the bright 100 spots blend with the surrounding way better then with older shooting formats... So you need to know the camera, do plenty of test with zebras set at 100 (that for all things considered indicate overexposure). Also don't be afraid of little bit of zebras at 100 in your image, as long as it doesn't overtake your image you are ok.

Similar to Patryk's comments, our cams are set to both, and I'll flip back/forth when setting up a shot, and then leave at 100. I don't mind at all if there is a tad of zebra in the shot. Many shooters are terrified of zebra at either level, and end up underexposing the shot (which isn't nearly as bad as over exposure).
One camera we have only has one setting, so we leave it to 70, and let zebra indicate the usually-hot spots of forehead or nose.

Thanks for breaking this down into terms easily understood. It really did make sense once it was broken down this way.


Cliff Etzel - Solo Video Journalist
bluprojekt | solo video journalism blog

Let me add one one word of warning. Zebras only work under WHITE lighting. If you're shooting stage productions set exposure using your zebras under full lighting and do not chase exposure.
The best instument for judging exposure is an RGB parade however very, very few cameras offer these. They do let you see what is happening in each channel.
With stage lighting it is very easy to clip one channel just relying on zebras and the results of that can be very ugly.

And using 70% zebras for skin is good if the subject is caucasian without a deep tan. My indian performers are another matter entirely :)

Bob.

Shooting 70 for interviews is only good if everyone you shoot has the same skin tone. Imagine what's going to happen if you're shooting a fair-skinned Irishman one day and a dark-skinned Ethiopian gentleman the next, relying on the zebra set at 70 for both.

Can you guess what the outcome will be?

...even some areas with zebras at 100 still retain some color information

That's because the zebra settings are based on what used to be called IRE, Institute of Radio Engineers..., and as you can imagine those guys were shooting with analog cameras and wanted a 10% safety.

If you compare video of an ebony Ethiopian and an ivory Irishman, then check your vectorscope, you'll see their skin is at exactly the same angle.

The reason for this is that the characteristic skin color angle on a vectorscope is dominated by the color of hemoglobin in the blood, which humans all have to about the same extent.

This means that to a video camera we all look the same... :O)

It's been much discussed whether to expose ebony differently from ivory, but it's easy to see that if you expose both to the same setting on an exposure meter they will both have the same luma level, i.e. they will look too similar.

In practical shooting, you may have to tweak the lighting setup to avoid losing detail in the ebony face, without changing the overall exposure of the face.

Look at old portrait photos (or film) of Louis Armstrong, you'll immediately see what I mean.

So here's a question:

If I used a white card and metered off that so that it just barely registered with Zebras - wouldn't that theoretically give you a base line and then all tonal values would fall accordingly?

I worked with the zone system extensively when I shot b/w film back in the day and this is a rudimentary idea of setting a given tonal value and letting the others fall accordingly - of course when you shot analog you would then have the option of exposing and developing (N+1, N-1, etc) accordingly for the given contrast range of the scene when metered with a properly calibrated spot meter. Once could even go so far and use auto exposure on an 18% gray card (Zone V) and then lock the exposure by going to manual mode - is this the same for how video exposure values would work?

Cliff Etzel - Solo Video Journalist
bluprojekt | solo video journalism blog

"If I used a white card and metered off that so that it just barely registered with Zebras - wouldn't that theoretically give you a base line and then all tonal values would fall accordingly?"

Yes. This is pretty much the same as using a light meter.
Works best when you can setup your lighting, using a lightmeter is the way to go if applicable to what you're shooting i.e. setups in a studio or with a crew and grips etc outdoors.

Bob.

THis was my thinking for the controlled lighting situations I am shooting and knowing that now gives me a baseline by which to work.

Thanks for confirming my original thoughts on this.

Cliff Etzel - Solo Video Journalist
bluprojekt | solo video journalism blog

Bjorn, we weren't talking about using vectorscopes, we were talking about using zebras.

Set the zebra at 70 and using the zebra alone in the two examples I gave, and you will run into serious exposure problems.

we weren't talking about using vectorscopes, we were talking about using zebras.

Bob made a very good point about zebras showing only luma across the R, G, and B channels without regard for any individual channel overloading, as would be apparent in an RGB parade (such as can be seen in Vegas).

After you were talking about the luma of faces, I added a note about the chroma of faces, and made a point about the exposure of black faces vs. white faces that attempted to give the actual reasons for what you were trying to say with a question.

I hate it when people just do things because they've been told, without understanding any of it. This is not good for creativity, and it's not good for a professional's ability to solve whatever problems may come.

Jay, you are hereby stripped of all libertarian honors and awards, and your epaulets will be removed in a ceremony at dawn.

:O)

I hate it when people just do things because they've been told, without understanding any of it. This is not good for creativity, and it's not good for a professional's ability to solve whatever problems may come.

Bjorn, I'm afraid I'm going to have to disagree with your statement. A person does NOT have to understand all the intricacies of ______ (fill in the blank) in order to use it creatively. Just because an individual cannot spout off a litany of technical jargon does not prevent him from solving whatever problems may come.

Too many people in too many forums have proven this to be true. And if that weren't enough, too many bad videos by techno-geeks on the Internet prove it beyond a shadow of a doubt.

As the old adage says: "Talk is cheap."

Understanding is not talk.

No talk is inferred from understanding.

I speak out on a regular basis against academic "parrot" types who can only repeat what they heard, in order to impress others with their great knowledge, even though they don't actually understand what they are saying.

I also speak regularly about the huge explicit step between knowledge and understanding, and about the next step after that, which is "skill."

Skill is beyond just understanding something on a deep level, it is actually being able to use an understanding in practice.

Now, it is true that someone can be successful by following a step-by-step recipe without any understanding at all. That's been shown many times.

The problem is that due to a lack of understanding they can't be creative beyond what luck can give them.

Anyone can choose a preset to get a certain look. For going beyond that, understanding is necessary for the professional (to be able to deliver even if luck isn't present for a particular delivery), while luck may be sufficient for the amateur whose livelihood isn't at stake.

I suspect we agree on the key issues here, but talk confuses easily.

Well, on this particular subject, we'll have to settle on disagreeing agreeably.

I am always grateful when things can be disagreed agreeably :O).

I became a mediator when my parents disagreed on just about everything, and even when I couldn't get them on the same page, they were often laughing when I showed them irrefutably that they were looking at exactly the same thing from two very different angles. And they stuck together for life, which was pretty cool.

You made the following three points, and I don't see where we disagree:

1. A person does NOT have to understand all the intricacies of ______ (fill in the blank) in order to use it creatively.

We agree. I never said that all the intricacies need to be understood. I just said that more understanding allows for more creativity (but see 2. below).

2. Just because an individual cannot spout off a litany of technical jargon does not prevent him from solving whatever problems may come.

We agree. Having the language (terminology) is not related to being able to solve the problem. But to solve problems that come up, he will need either knowledge, luck, or persistence (the latter really means developing his own knowledge without outside input).

3. Too many people in too many forums have proven this to be true. And if that weren't enough, too many bad videos by techno-geeks on the Internet prove it beyond a shadow of a doubt.

We agree. Those who only know how to press preset buttons without having artistic talent have proven this many times over. I don't know which forums you go to, but I spend most of my time in the forums of working professionals who have something at stake such as paying their mortgage or not. That tends to reduce the nastiness very quickly. It's academic debate that gets so nasty, because it doesn't cost the participants anything to be ugly in their argumentation.

I've been active in many fields and have always found that the absolute top people in any field are very humble. It's one level down where things get ugly.

At this level, where people are top athletes/artists/engineers/scientists/etc. (just not #1 in the world!), they tend to think, "Hey, I'm great! I know everything! Everybody else should just listen to me for the definitive answer."

At any given time, one of these people will with great effort go on to be #1 in his or her field. In the process they discover that there is no such thing as "knowing everything." The universe is for all practical purposes unlimited, and this is very humbling for those who strive to go all the way.

They see that perfection is a process, not a goal.

I don't suppose we could agree on this agreeably, could we?

:O)