Setting exposure, I need another lesson

[Doug Jensen]

Hi Luc,

I've rarely run into the scenario you describe, but maybe it's pretty common around Belgium and the North Sea. :-)

You are correct that zebras would be of little use in such a situation. There are several methods I might use to set the exposure, but I can't say which one would work best unless I saw the actual situation. Here's some thoughts:

1) If the sea and sky are flat and gray, I might pan the camera over to either side, or even behind me to find a boat, car, sign, building, seagull, or anything that will show me a nice clean white. I'd set my exposure on that, and then re-frame for the sea. With flat lighting, the exposure ought to be about the same in any direction.

2) I'd switch to auto-exposure momentarily, let the camera find the exposure, and then switch back to manual and drop it down one f-stop. In my experience with flat lighting, that will be pretty close.

3) I'd just use my instincts and my experience with my camera to choose an exposure that looks correct to me on my monitor or viewfinder. I wouldn't do it with a new camera or a rental, but with my own equipment, I have a pretty good feel for what constitutes a correct exposure. Since the lighting is flat, I could be off by a stop or two and it probably won't make any difference at all.

Just some ideas. There are proabably other ways that would work just as well.

[Anton Strauss]

Originally Posted by Luc De Wandel

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.

if there is nothing white in the scene, I hold a white card (always in back pocket) in front of the lens and I set exposure so I just see a touch of zebra (my zebra is preset to 100%)

[Luc De Wandel]

Yeah Doug, unfortunately that is very true for the North Sea coast and Belgium, especially this time of year. All kinds of grey, as far as the eye can see :-(
Thanks both of you for the tips, I guess getting to know and interpret what you see in the VF is essential anyhow.

In the old days of analog photography, I could judge, just by looking around, what aperture and shutter speed I had to choose. I'll come to that in video too, one day. When I'm very old...

[Daniel Larson]

I set my viewfinder to accurately display colorbars and don't use zebras at all. When I expose for a scene I open the lens until the viewfinder just starts to loose detail and then close it until the detail comes back nicely, maybe rock it back and forth between the two to find the sweet spot where the image is rock solid, and that works 99% of the time. And there is always enough of an image where I can tweak it in FCP if needed. I'm also the only person that uses my F335 and that probaby helps me a lot too.

- Dan

[Simon Wyndham]

I set my viewfinder to accurately display colorbars and don't use zebras at all. When I expose for a scene I open the lens until the viewfinder just starts to loose detail and then close it until the detail comes back nicely

A lot depends on the type of situation you use the camera in. If you shoot a lot of stuff where events happen unexpectedly and you need to be ready to get the footage at a moments notice you need all the help the camera can give.

[Greg Boston]

Originally Posted by Luc De Wandel

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.

Another tip about low contrast situations would be to use the standard gamma which has more contrast than the cine gamma curves which tend to be flatter to maximize exposure range. The standard gamma is more vertical which provides more change in sensor output with less change in light level.

-gb-

[Luc De Wandel]

Thanks for the tip, Greg. I'll try that next time to see the difference.

[Gary Nattrass]

I am lucky that my camera (HPX301) has zebras, a histogram and a very good LCD screen and finder.

They are all still a guide though as stated previously but I suppose the more information you have the easier it becomes to judge exposure, I also have a good light/spot meter and have checked readings from it against what I see in the viewfinder and on the zebras which I have set up to BBC spec.

I suppose it all comes down to experience and as like Luc I have done stills since the early 80's you get a feel for what will be OK but on recent drama shoot I exposed a clock shot for what the director wanted but when the producer saw the rushes he wanted it lighter. A few tweaks in FCP and he was happy so it is comforting to know that the AVC intra 100 10 bit 4.2.2 footage can still be pushed quite a few stops in post if we are desperate.