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Old January 7th, 2007, 04:53 PM   #1
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What's the best way to diffuse?

I have recently purchased an on camera light for my XL2: the Bescor CK7XLR Battery and Light Kit.

http://www.bhphotovideo.com/bnh/cont...ughType=search

I was looking for some tips on the best way to diffuse the on camera light to be used at a Sweet 16 Party. Here are my main concerns: 1. I don't want to spoil the party atmosphere by the light being to bright, or 2. Have the light so dim that it doesn't really help out at all, and 3. Be able to quickly increase the output from the light for a more formal interview with guest at the party.

Here's the solution I'm working on, please let me know if there is a better way to accomplish what I'm trying to do.

I am cutting Bogen 12x12 light filters to about 6.5 x 6.5 and then making cuts toward the center on the corners at 45 degree angles

Then I fold the outside edges up and wrap the ends around one and other and staple them together. This gives me a kind of square bowl. I then use small binder clips to attach it to the barn doors.

The main flaw I see in this setup is that I believe that I will be layering the filters, a diffusion filter and a .3 ND. I think this will make it difficult to remove the .3 ND on the fly for a slightly brighter interview of a party goer.

Any suggestions would be greatly appreciated,

Thanks in advance,
Kevin
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Old January 7th, 2007, 07:01 PM   #2
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Kevin,

The box idea is interesting. You might be able to make something out of Foamcor. Paint it silver inside, or line it with crumpled tin foil, to make a small softbox. Cover the front with diffusion. Use velcro to attach the front diffusion screen and then you can use anything you want as the diffusion on the front, just put some velcro on it. Attach it to the barndoors and leave a little room for the heat to get out and cool air to get in.

35W will be a decent amount of light, especially if you use the factory glass diffuser. For more light and less diff, tip the glass out and use a lighter frost, Opal, or 251( half the "thickness" of 216 difusion) in front of the light. Just clip it to the barndoors with a couple of clothespins. Brushed Silk is nice because it spreads the beam so it actually geta a wider beam. Two layers with the striations perpendicular to each other will make a larger circle of light.

You can probably get a 20W bulb, if you are worried about the 35W being too bright. If the ambient light is at a higher level the camera light won't be as noticable. It's when the lights are low, then it can become potentially bothersome to others. But, you need light, there's no way around it.

With onboard lights, I sometimes bounce the light off the ceiling and have the top barndoor covered with crumpled tin foil and then tip that in to get some fill in the eyes. works best on low, white ceilings. That technique won't work in a large church. You can also get a larger light on a stand, bounce it off the ceiling and then use the on camera light as the fill light.

You can buy sheets of Rosco, or Lee diffusion material for about 6 bucks per 18"x24" sheet. A well stocked camera store, or theatrical supply house will stock them.

Sometimes it helps to point the light at the ground when you turn it on and then bring it up, that way people get used to it for a few moments before it's pointing right at them.

The battery you have is 85Watt hours so, divide the 35W bulb into that and you'll get 2.4 hours of light. It's good to have a second battery, just in case.
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Old January 9th, 2007, 10:17 AM   #3
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Mark,
I ordered up the 20 watt bulb and an extra battery. Following your math on the life of the battery, 85 WH / 20 watts = 4.25 hours of light off of one battery. Is that right? I was just wandering because the Bescor website list the time on that battery as 150 minutes, about the same as you stated earlier. I think I'll be fine with the lower wattage bulb and some extra diffusion in front of the glass. I'll be keeping the factory diffusion in front of the bulb too.

I just wish that B&H had listed the 20 watt bulb as an accessory for the Bescor light to begin with. Not only do they not list it, it is a special order item for them and there is no way if I ordered from them it would get here in time. I ended up ordering from a competitor out of New York and having to pay rush shipping. I hate paying more for shipping than the item cost!!!

Thanks again for your help, Mark...

Kevin
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Old January 9th, 2007, 11:13 AM   #4
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Kevin,

You're welcome. The glass might be fine by itself. With the 20 watt bulb, you might want less diffusion, clipped to the barn doors. That way you aren't killing your light. By making the source larger, you are softening the light. Your homemade mini softbox makes the light softer because you are using diffusion and also because it is a larger source. Nothing fancy, just a foamcor, or even cardboard box clipped to the doors. Or, go super simple and just clip a 6, or 8 inch piece of diff to the doors and call it good. That's what most people do. It is a larger source. It's very compact and quick. 2 clothes pins (aka C-47's) and you're done.

Yes, Watt Hours are derived by taking the Wh of the battery and dividing by the wattage of the light. So 85 Watt Hours divided by 20 Watts equals 4.25 hours of run time. Just be sure you don't deep discharge the battery. It's not good to go until the light goes dead. Also conserve power by turning the light on only when you are shooting.

You can get a work light or even a clamp light with a photo flood and bounce that off the ceiling and then use the onboard light as a fill. Maybe turn it off and just go with the onboard for the blowing out of the candles, but give yourself a little help with the lighting. You're in control, but be wiling to be flexible. If the lights are already on when guests arrive, that might be helpful, then they aren't blasted when you turn the lights on.
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Old January 14th, 2007, 05:22 PM   #5
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Kevin,

You can buy replacement bulbs for your light at any Home Depot, Lowes, or other major hardware store. There's no difference between the hardware store bulb and the video store bulb. Just take in the current bulb to make sure the ends are the correct size and check to make sure that your buying a DC bulb, not an AC bulb. It will save you a lot of money on shipping.

Ben
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