The difference in Photofloods & Practicals?

Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

[quote author=magicdavek link=board=lighting;num=1078080402;start=0#11 date=03/08/04 at 20:03:52]
Hey Barry, any suggestions? (inexpensive approaches preferred)[/quote]

I'm coming to this discussion late, so let me make sure I'm addressing the right thing: you're looking for "sunlight" solutions, the cheaper the better, right?

Okay, to regress: you asked how the "big boys" do it... they primarily use Kino Flo's (with daylight tubes) for soft light, and HMI's for hard light. Kino Flo's are, of course, fluorescent fixtures with special lamps that are extremely accurate in color rendition, and you can get those lamps in either tungsten or daylight colors.

HMI's are a unique light source, they're basically like a crossbreed between a fluorescent and a tungsten hard light. They have the daylight color of a daylight-fluorescent, and the high power efficiency of a fluorescent, but the kind of light they put out is the same as you'd get from a tungsten: punchy, powerful hard light. So for hard light sources, the big boys use HMI's. HMI's can be VERY powerful, too: small units are 575 watt, but put out as much light as a 2,000 watt tungsten unit would. (Which gets even worse: you'd have to gel the tungsten light with blue if you wanted it to match sunlight, so you'd actually need 8,000 watts of tungsten to get the same punch of blue light that you'd get from a 575w HMI!)

HMI's are, of course expensive!

So are Kino Flo's.

So let's ignore those. You want cheap solutions?

The cheapest solution is to use a mirror and redirect the natural sunlight. Professionals use "mirror boards", which are big glass mirrors mounted in a yoke that can be mounted on a c-stand and directed wherever you need. The problem with using a mirror is that the sun MOVES, and it moves very quickly through the sky, and every inch it moves means you have to reposition the mirror.

"Shiny boards" are another solution, they are basically like a mirror board but instead of being a glass mirror, they're a big silver reflective surface. Still gives a strong hard light, nowhere near as efficient or hard as a mirror board though.

But those probably aren't the solution you're looking for -- they require a direct line-of-sight to the sun, which many times won't be practical. And, they require direct sunlight, which means on an overcast day they're completely useless.

Other ways of getting a "sunlight" look would be to use daylight-balanced photofloods (as has been discussed heretofore) or daylight-balanced fluorescents, or gelling tungsten lights.

Photofloods can be a reasonable choice, for a short while. The bulbs do change temperature and they do have a short life. But they're about the cheapest reasonable way to get a splash of sunlight.

For fluorescents, the great thing about the DVX is that you can tailor in the shutter speed to eliminate any flicker. So you could use some $20 fluorescent fixtures down at Lowe's, and buy some specific daylight tubes. There are tubes made in almost every color, although lots of the daylight tubes are 6500k. That's not the 5600k preset, but it's not really bad, either, they'll just look a little bit bluer on tape. You can always gel 'em down to get closer to 5600, with maybe a sheet of 1/8 CTO.

But for sunlight, you want hard direct light. Sunlight is the hardest, punchiest light source in the known universe. So you'd want a small pinpoint light source, like a photoflood, or you could use the Lowe's worklight with some blue gel.

Perhaps the cheapest practical solution would be a Lowe's worklight, with some blackwrap around it to make "barn doors" or a snoot, and then a sheet of CTB in front of it. You'll need a fairly strong light, because CTB gel costs you about 2 stops, so a 500 watt halogen bulb is only going to deliver about 125 watts worth of "sunlight". So get a 2,000 watt worklight pair, make a homemade blackwrap snoot around it, put a blue CTB gel in front of it, and you'll have 500 watts of "daylight" streaming into your scene, all for $50 or less.
 
Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

I have printed and saved this reply!
 
Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

Thanks, Barry. This really helps A LOT. I have to do some extensive vignettes (a lot of short dramatic scenes for parenting videos) and I want them all done during the day. That's why I was asking about that kitchen lighting in commercials (see above).

In addition to any light set up i create, I have very bright recessed lighting in my kitchen (five 120 watt Phillips reflector floods-man I hate when my kids leave the kitchen lights on!). I think I'll try putting gels over them, but I didn't realize you lose two stops with gels. My powerful kitchen lights won't be so powerful.

I'm no physicist, but I'm surprised to hear that you can get a 6500k fluorescent down to a 5600k with a CTB gel. Am I to infer that it doesn't matter what the color temperature of the light source is, the gel gives you what you want? (If it's not obvious by this point, I've never used gels before.)

Also, thanks for explaining the difference between Kino Flos and HMIs. If been looking at description of them at B & H, and at their respective companies websites, but didn't have a grasp of the difference.
 
Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

Gee, I just thought of popping in a daylight corrected photoflood in each recessed lighting cannister. I've used the blue photofloods before, and have only used 250w and 500w. I wonder if they have 150w or 100w. On the other side of the kitchen, I have a chandelier with five 100w bulbs. It's ridiculously bright (so I installed a dimmer so we don't go blind). If there were lower wattage photofloods (is that an oxymoron?), I could use them in the chandalier. Make sense? I'd still need a key light but may not need a kicker due to all of the overhead light from the recessed lights on one side and the chandelier on the other. I won't be starting the shoot until later this spring at the earliest, but i don't want to be figuring this out the night before.
 
Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

(Above I said)
I'm no physicist, but I'm surprised to hear that you can get a 6500k fluorescent down to a 5600k with a CTB gel. Am I to infer that it doesn't matter what the color temperature of the light source is, the gel gives you what you want? (If it's not obvious by this point, I've never used gels before.)


It also must be obvious that I don't know how to read. I reread Barry's section and noticed that he said use a 1/8 CTO gel to get the 6500k light down to 5600k. Now if I only knew what "1/8 CTO" means. (I'm proud of myself that I know what CTB means! Hey, I do event videography. I deal with existing light most of the time-now I have some projects that require a cinematic lighting).
 
Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

CTO is Color Tempature Orange!

Just think in opposite terms:

CTO (Orange) corrects to BLUE or cool

CTB (Blue) corrects to ORANGE or warm
 
Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

CTO is "color to orange". It corrects daylight-colored light sources to be tungsten-colord. The fraction indicates the strength (i.e., a full sheet, for full correction of 5600 to 3200, would be a sheet of CTO. A sheet that only does half that much correction would be 1/2 CTO, and there's 1/4 and 1/8, etc). The correction from 6500 down to 5600 is pretty minor, so I'm sure 1/8 would get you in the ballpark.
 
Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

You mean I have to use math!
 
Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

Does the fraction affect the light output? Earlier you said that putting a gel on the lights would have an impact of 2 f-stops. Was that because you'd require a full (i.e. not fractional) gel? Thus, the 1/8 CTO going from 6500k to 5600k may not require the f-stop adjustment?
 
Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

Using the CTO or CTB will definately require exposure adjustment, but here's the deal with the DVX.

Unlike traditional film, the DVX100 is more or less WYSIWYG. I wouldn't even be concerned with the hard numbers when in reality you can hit the AUTO IRIS button or use Zebras or adjust from monitor...

Thats my take.
 
Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

Yes, every gel will cut the light some -- that's an immutable law, because unless the gel is 100% optically clear, it's going to impact the light output.

A full sheet of CTO costs about 2/3 of 1 stop. A full sheet of CTB costs almost 2 full stops. So a 1/8 CTO (to go from 6500 down to 5600, which may require 1/4 or 1/8, I'm not sure) is going to have a completely minimal effect on exposure. It will cut the light output down a little, but very little... I mean, 1/8 would cut the light 1/8 of 2/3 of a stop...
 
Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

That seems to be yet another reason to use fluorescents-more flexibility with exposure when putting gels on lights.

That article on the Studio1 website advocating fluorescents was very interesting and compelling. Anyone else read it?

www.studio1productions.com/Articles/FL-Lights.htm
 
Re: The difference in Photofloods & Practicals

Re: The difference in Photofloods & Practicals

Thanks for the article! Im reading it now!
 
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