LED lights and imag

[unc417]

We have a small stage, 30ft wide by 25ft deep with a 12ft ceiling, with 12 source four pars and 14 chavuet led's over it. We have two Sony PD170 cams. My problem is, wide shots on the cam look terrible. I suppose the brightness of the led's makes the cams adjust the light levels down and people get dark. Close up shots look decent.

We are an all volunteer team and unfortunately I know of no professionals in the area to bring in to help us out. I've heard that led's are known to cause problems with cameras? Or is there something with the cams that need to be adjusted? As a team, the cameras are our weakest point, knowledge-wise. We leave everything to auto, though sometimes we do manually adjust the brightness level if the picture is dark or washed out.

One other issue, and this may be more of a lighting thing. When our pastor is directly in front of the cam, it looks fine, but when he walks over and is at an angle, his face gets all washed out and ghost like. And this is a close up shot. Our primary front key lighting is currently 4 source four ellipsoidals, though I am adjusting 4 source four pars with bamber gels and will try that soon to see what that looks like. thanks

[Esoteric]

There could be a variety of issues here.

1. No, there is no particular issue with LED lights and video. The only issue you MIGHT have (and none of my units have this issue, although I personally do not sell the $100 Guitar Center Specials so you might have issues with those) is flicker, and if you do, then take a look at your shutter speed and that will fix it.

2. The brightness issue can happen with any light. Usually you don't want your background too bright or too dark as the camera will have a very difficult time adjusting to the difference. So you will need to work with the lighting levels to even that out.

3. Another problem you might have is an uneven wash. You will have to work to even out the wash but it is possible.

I am going to post articles on my website soon about #1 and #3.

Mike

[tdangelo]

Originally Posted by unc417

We have a small stage, 30ft wide by 25ft deep with a 12ft ceiling, with 12 source four pars and 14 chavuet led's over it. We have two Sony PD170 cams. My problem is, wide shots on the cam look terrible.

I guess the first comment should be that your situation is likely not unique. So, join the team as what you describe is reflected in many church videos.

The main issue you are describing is balance between foreground light and background light. When the camera is zoomed in tight this appears to be less of a problem because the field of view is smaller (you are seeing less of the background). However on a wide shot you are seeing more background including the unevenness.

Originally Posted by unc417

I suppose the brightness of the led's makes the cams adjust the light levels down and people get dark. Close up shots look decent.

It is likely not a LED (verses another type of light) issue. But it very well may be how you are using the LEDs. If the relative illumination of what the LEDs are focused on is substantially higher than the relative illumination of the subject (the Preacher), AND the camera is set to auto-iris the camera will adjust to the brighter area of the image by closing the aperture of the lens thus letting in less light. This results in not only the background being reduced in level but the foreground, the subject (the Preacher), being reduced in recorded light level as well. Putting the camera in manual iris will make it easier to see what portions of the scene/picture are out of balance and require attention.

Originally Posted by unc417

When our pastor is directly in front of the cam, it looks fine, but when he walks over and is at an angle, his face gets all washed out and ghost like. And this is a close up shot.

Here again there is a lighting balance issue. Remember, when the subject moves and creates a new angle of lighting instrument to camera a light which was a key a few moments ago may now act as a fill. A fill may then act as a back light. Etc.

Many years ago I was doing video for a corporate event which someone else was lighting. All during rehearsals the client complained about how bad the cameras looked. Of course, he was blaming the gear … not his lighting guy. At the meal break the lighting guy turned off all his lights leaving only the general house lights on. The client looked at the monitor and said, “why do the cameras look so much better now, what did you do?” I think he eventually figured it out that the lighting guy may of known what he was doing theatrically but hadn’t a clue how to light for TV.

Fast forward twenty years later and on one of my first network TV, live multi-camera jobs I was amazed to see during four days of rehearsal the senior video guy (the shader) set all the cameras to one F stop on the morning of the first day and didn’t touch a paintbox for the next three days. I asked him why he was doing that and he said that it forces the lighting designer to light the scene well. Once we got to dress rehearsal and the telecast he touched things up on each camera … but if he started making up for the lighting design deficiencies earlier on the end product would have suffered.

Hope this helps.

- Tom

[Esoteric]

Yeah, never count on video to make up for bad lighting. Of course, never count on an LD to make up for a bad DC. Well, sometimes we can, but don't count on it.

Mike