DV Info Net

DV Info Net (https://www.dvinfo.net/forum/)
-   Canon XL and GL Series DV Camcorders (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/)
-   -   Zebra on the XL2 (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/114309-zebra-xl2.html)

M.J. Hasty February 8th, 2008 11:38 AM

Zebra on the XL2
 
Hi,
I'm practicing lighting for interviews with a basic lighting kit. I'm using a 500w tungsten floodlight bounced into an umbrella for a soft key and a 250w (same set-up) for a fill ("Rembrandt" positioning, more or less). I know this is not much light by professional standards; so I wonder why I'm getting zebra all over the actor's face? I have the zebra set at 80, just turned it up to 100, still getting some zebra lines, though less with the higher setting.

I'm using the auto-presets for everything (such a newbie), so this is lprobably part of the the problem. But I wonder why the presets would reject this minimal lighting?

Any feedback greatly appreciated.

MJ Hasty

Richard Hunter February 8th, 2008 07:10 PM

It's not the amount of light that's the problem it's the variation between bright and dark areas. The autoexposure uses average levels to adjust everything, so if part of the frame is darker the camera will set a brighter exposure. This means highlights will clip, as you are seeing.

Your best bet is to use the camera manual features in this case. You can start with Tv mode, and set the shutter speed to 1/48s (if shooting 24p) or 1/60s (if shooting 30p or 60i). The camera will adjust the aperture until it is happy with the average brightness level in the image. If the subject highlights are over-exposed, push the Exposure Lock button and then adjust the iris rocker until the zebras are gone. If the image is then too dark, you can compromise a bit and adjust the iris until only the brightest extremes are showing zebra, but since you are using lights, preferably you should adjust them until the highlights are not so glaring and the darker areas of the subject are well lit (if that's the effect you want).

You can also change the way the camera responds to different lighting by playing with the gamma curves in the customize menu. For example, Normal gamma will show generally brighter images than Cine gamma.

Richard

Michael Nistler February 8th, 2008 08:43 PM

Quote:

Originally Posted by M.J. Hasty (Post 822662)
Hi,
I'm practicing lighting for interviews with a basic lighting kit. I'm using a 500w tungsten floodlight bounced into an umbrella for a soft key and a 250w (same set-up) for a fill ("Rembrandt" positioning, more or less). I know this is not much light by professional standards; so I wonder why I'm getting zebra all over the actor's face? I have the zebra set at 80, just turned it up to 100, still getting some zebra lines, though less with the higher setting.

I'm using the auto-presets for everything (such a newbie), so this is lprobably part of the the problem. But I wonder why the presets would reject this minimal lighting?

Any feedback greatly appreciated.

MJ Hasty

Hi MJ,

You didn't say the distance between the lights and subject, the aperture/iris setting, the shutter speed, gain, etc. But if your in automatic mode, I'm not surprised you see zebras when you're preset to 80 IREs. At any rate, typically we don't use zebras when we shoot in AUTO - a bit of an oxymoron (no offense).

FYI - 750 watts of soft (unbrella) light isn't "minimal", especially in a household room at close distances.

Good luck, Michael

Josh Keffer February 10th, 2008 11:37 PM

Great reply, Richard.

MJ, manual settings are your friend in this case. As Richard suggested, starting in TV mode may prevent you from being overwhelmed by all the controls in Manual mode while helping you to get a proper exposure. Learn to adjust your camera to get a good exposure, then you can start exploring some of the advanced adjustments that will also help you to fine tune your image.

Also, if you're ever struggling with too much light, try moving the lights further away from the subject. The Inverse Square Law comes into effect here. In practice, it means that if you double the distance between your light source and the subject, just one quarter of the light will hit the subject.

Keep working with it, and don't get discouraged. The XL2 is an amazing piece of equipment, but it can be a bit overwhelming at first.

Josh


All times are GMT -6. The time now is 04:19 AM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2021 The Digital Video Information Network