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bulb / lamp recommendation for Lowel Rifa 88

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Ian MacLean
bulb / lamp recommendation for Lowel Rifa 88
on May 29, 2009 at 6:03:51 pm

I'm setting up a greenscreen studio in a small room (12'x14').

I've decided on a Lowel Rifa 88 as my key light, and want to get the big one for max surface area. As the quarters are cramped, I don't think I'll be able to back it off more than 5 or 6 feet from the subject.

I have a new Panasonic HPX170. I'll be able to tune exposure with a built-in waveform monitor.

I'm guessing the 1000w lamp the unit comes with will be too powerful, and can order additional lamps in 750, 650, and 500 watts.

I can also get the TH-X300 lamphead, and lamps in either 300, 200, or 100 watts.

My question is whether a 500w lamp will still be too much light, and I should get the spare lamphead. Also general recommendations on the range of lamps. Many thanks.

ps filmtools has an EHD Ushio lamp for half the price B&H is charging. Is there any problem with the brand or distributor, or should I just buy from them?


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Dennis Size
Re: bulb / lamp recommendation for Lowel Rifa 88
on May 29, 2009 at 8:37:17 pm

You can always make a light that's too bright less intense (via dimmer, scrims, neutral density, or even backing it off). It's tough to make it brighter when you really need it.
The real issue is how bright your greenscreen is and what else you're using to light your subject -- hopefully you have several more lights in this studio.
300w or less won't provide the necessary output. My gut tells me the 750 is the correct choice, but you could get away with a 500w. I'm guessing the 500w should provide about 60fc on your subject.
Everyone has their opinions about which brand of lamp is better than the other. I never felt it mattered.

DS

P.S. with a room 14 feet you can't get your light more than 6 feet from the subject?



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Ian MacLean
Re: bulb / lamp recommendation for Lowel Rifa 88
on May 30, 2009 at 6:11:41 am

Thanks for the info. Knowing nothing, my guess matched your feeling as well which is encouraging. Second opinions welcome.

The subject needs to be at least six feet from the screen, and the backdrop stands and camera tripod are also going to cheat my distance down a little. I've also got other furniture in the room that's inconvenient (a chest holding the computer / raid, MX02, etc).

I may buy a 500, and a 650, try them, and if they're still too hot look into the other lamphead. Although I suppose I could also look into putting neutral density in front of the front diffuser of the Rifa 88. Would that hinder the light's ability to shed heat? And what would a sheet of that cost, typically? Many thanks.


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Dennis Size
Re: bulb / lamp recommendation for Lowel Rifa 88
on May 31, 2009 at 2:27:08 am

I believe the 650w is only for 220voltage. Get the EHG 750w lamp. It's the workhorse and has incredible lamp life (2,000 hours) -- a bargain for the cost.

The neutral density .6 will cost you a "whopping" $8.
It would be wiser to buy a 1000w dimmer.
That will offer you more options. Don't limit yourself. Remember the albino subject will take a lot less light than Danny Glover will. Besides that, the other fixtures illuminating your subject will add more light level to the overall mix.
How many fixtures are on your background?

DS




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Ian MacLean
Re: bulb / lamp recommendation for Lowel Rifa 88
on Jun 1, 2009 at 3:40:47 am

Right you are on the 650, thanks. And thanks again to this list and the expert advice.

See new post on backdrop.


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Mark Suszko
Re: bulb / lamp recommendation for Lowel Rifa 88
on Jun 2, 2009 at 2:51:23 pm

I am a huge Rifa fan, we have them in several sizes. I would hope you got the eggcrate directional diffuser for it, that will help you put the light just where you want it and not on the green screen, while still having that Vermeer-like wrap-around quality we like.

The eggcrates are freakishly expensive for Rifas if bought stock. We couldn't afford them, so I have to use extra light stands and foam core to flag the Rifa light off of backgrounds when in studio settings. I keep meaning to try making my own, but have not gotten around to trying it yet. OTOH, I use my biggest Rifas to light my green screens evenly, and they make it easy to do.

Dennis, at the risk of starting a big fight, and recognizing your resume' greatly outweighs my own, I take exception to your statement that it takes "more" light to light Danny Glover than a caucasian actor. One of the number one mistakes beginning lighting people make is thinking that dark skin somehow needs "more" light, and they blast the subject with thousands of watts. I believe it is not the case at all, more like how you angle the light and control contrast ratios is the trick. With darker skin the trick is to bounce the light thru the translucent outer layers of dermis, and I try to do this by angling more off to the sides than usual.

Also, lighting dark skin is about letting it show shape thru specular reflection and specular highlights, and thus to define contour, same as you do with lighting chrome or glass shapes, so I like to use large bounce cards close-in and along the sides to achieve that, preferably in a gold or bronze foil, to warm them up a little, but plain white foamcore will also work, just reads as "cooler/bluer". And it doesn't take a lot more light to do it than it does for caucasians. You can't count on auto-iris to get this right; dark skin against white shirts is too much for it to figure out, go manual, then you may have to use half-screns, dots or nets or other shaping and diffusion tricks to control how much the white shirt gets lit versus the dark face. But you don't win that fight by over-lighting.

A fascinating tip Rich Harrington pointed out to me in one of his COW tutorials on color correction is that when color balancing shots to correct for skin, the skin tone, black or white or tan is not what we're actually working with; when we're looking at the skin tone line on a vector scope, we're balancing the color of the blood under the skin, which is the same color all the time.

Seems our cameras are already built for diversity:-)


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Ian MacLean
Re: bulb / lamp recommendation for Lowel Rifa 88
on Jun 2, 2009 at 7:06:31 pm

Thanks for that. I went round and round on my options, and Boy Howdy are you dead-on about the cost of the Lowel egg crates. However, I couldn't get around the benefits of really nice, high CRI, controllable light and so bit the bullet and blew half my lighting budget on the Rifa 88 and eggcrate (40 degree).

I really love the modular design, and that if I have any future need to, I can have a big pretty softbox that will run of a huge range of bulbs, even off a car cigarette lighter, with the purchase of a few additional parts. Very cool, and I'm hoping I really like the light from the big diffuser.


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Mark Suszko
Re: bulb / lamp recommendation for Lowel Rifa 88
on Jun 2, 2009 at 8:14:42 pm

I like them better than Chimeras, myself. Very idiot-proof to set up and quick to tear down if you need to run and gun but still have nice lighting.

I was taught that with soft boxes you start with it placed at about twice whatever the diagonal measure of the box is, then bring it closer or further back to taste. That may be too intense for some shots. I still start like that when first setting up, but I generally wind up putting them about 3-4 times the diagonal measurement as the "working distance" now. I'm sure my methods would change for some shoots if I had the option of the grids.
The other fun I have with a Rifa on interviews is to place it closer-in and around 45 degrees for key, and put a plain foam core bounce card on a spare stand opposite for my fill, that's it, done. Looks very natural, doesn't "look lit"... but solves most of the issues of a shot that's really not lit. Not the answer for every case, but it works for my needs.


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Ian MacLean
Re: bulb / lamp recommendation for Lowel Rifa 88
on Jun 3, 2009 at 11:13:38 pm

Mark, thanks much for very useful info. Especially for anyone such as myself who hasn't used them before. I'm kind of assuming that those rules are for a softbox with the max rated lamp inside. If you have a variety of lower intensity lamps, I'm also assuming that would shorten the minimum distance, useful if you're working in a small room. Right? Again, thanks.


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Mark Suszko
Re: bulb / lamp recommendation for Lowel Rifa 88
on Jun 3, 2009 at 11:34:42 pm

If you never change bulbs, the square/cube law is your friend:-)


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