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Old Mar 28, 2010, 11:30 AM   #1
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Default The DIY Softbox is done!

Thanks to all for the advice as my softbox came together. I am preparing for portrait shots at a school fundraiser and I don't want to invest a lot into the lighting hence the DIY approach.

I figured that the idea is to generate a parabolic mirror to put all the light on target, and to diffuse the light to soften shadows. I gave up on the idea of creating a parabolic curve with any accuracy but decided there was much to gain from using an actual mirror to reflect the light. I set one 12" x 12" mirror behind the lights, reflecting straight out to the diffuser, and then I set four mirrors, at a 45 deg angle to the lights, to reflect at the diffuser. I filled in the gaps around the mirror with "aluminized polyester, or what passes for a mylar emergency blanket material.

I tried cotton for a diffuser, and it worked well to control shadows, but Chiffon gave me much more light with minimal penalty on diffusion.

I loaded the softbox with 8- 200watt equivalent CFLs that emit 5500k light, and I was able to get enough light to accomplish some decent practice shots.

I wanted to know what sort of impact the mirrors genuinely provided, as the assembly weighs qute a bit with them. I don't have a light meter, so I used my camera auto-exposure ability to tell me the story. I set up the camera on a tripod, shot the background, and recorded the settings. I then covered the mirrors within the softbox with more aluminized polyester and recorded the camera exposure settings.

I found that the mirrors increased the light by 2/3 of a stop at the background. Since the light is 8' from the background and the subject would be right in the middle, I figure the mirrors give me another 1 1/3 stop at the subject (light dispersion is exponential, but so is the exposure stops...).

I'm still struggling to blow out the white backdrop. but I'm getting close with 3- 200 watt CFLs.
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Old Mar 29, 2010, 7:03 AM   #2
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I should add a couple observations. For one, if a person needs a portable setup, it is clear that a strobe setup is the only realistic option, as the quantity of fixed lights is rather large. For an in-house set-up, 'steady on' lighting becomes an affordable option. Or perhaps a mix thereof.

I wonder how a person compares a watt-second values to fixed lighting. If a flash emits 100 watt-seconds, but for 1/1000 of a second, does it emit 100,000 watts of light for that 1/1,000 of a second? That value doesn't seem realistic, but the calculation method does... any insights there?
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Old Mar 31, 2010, 11:19 PM   #3
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Where are the pictures and instructions on this softbox? We want to see both the soft box and pictures taken using the soft box.
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Old Apr 4, 2010, 2:55 PM   #4
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Default Test Photo

I've attached a photo I took using the new softbox along with some backlighting. I used my on-camera flash stepped down 2 ev for fill. I also attached, I think, a 100% crop example.
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Old Apr 4, 2010, 3:02 PM   #5
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Default The box itself

Here's a couple shots of the softbox inner workings. I'd have to spend a bit of time to work up the instructions. For now I'll make simple mention of the lighting fixture - I used an outdoor electrical box coupled with outdoor lamp holders for the specific reason that these are highly adjustable and hold their position by virtue of their mechanism. Cheap, too.

Jim
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Old Apr 5, 2010, 2:14 PM   #6
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Interesting looking softbox, just a bit big for my taste but seems to work very well with the pictures posted.
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Old Apr 5, 2010, 6:30 PM   #7
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It's 36x36 at the diffuser, 2' deep.
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Old Apr 26, 2010, 6:38 PM   #8
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Your daughter seems to be getting the most adequate light. Your wife and son could use a bit more fill on the right side. Otherwise its a pretty decent softbox, good job!
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Old Jun 11, 2010, 2:59 AM   #9
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cool ! but it seems to be big
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Old Jun 11, 2010, 5:09 AM   #10
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Something out of Dr Who!!
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