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Wattage thoughts for ext. night?

Buddy Greenfield

Buddy Greenfield

I built a little rolling light boom for simple outdoor night shots, but I’m wondering what would be a general wattage to equp it with for illuminating a two-shot area (nothing fancy or all that big) from like 12 above/over and maybe 6 feet back out of frame (if I don’t boom over)?

I’ll be using halogen work lights and have 500 watts on it now, but I haven’t had a chance to test it yet.

From your experiences do you think more like 1k will be the ticket? Or more, or would the 500 maybe be do’able (For video)?


-Thanks-
 
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Ooooh, a lighting problem to start the Sunday morning with my coffee.

All the numbers here are hypothetical, and pulled from charts in Harry Box's Tech handbook.

12 above and 6 feet away should give you a distance (hypotenuse) of around 13 feet or so. (13.4....)

A 575 HMI (closest thing I can think of to a 500w halogen work light), according to Box's charts, is 20K candella, or about 89 ft/candles at 15 feet. The chart rates this at ASA 250, f2.8 +1/3 at 20 feet. (50 ft/candles).

Doubling that should give you f4 +1/3 at the same distance (15 feet) and ASA/ISO. Mileage will vary depending on your camera.

Figure that the 500w halogens are not as bright as the 575 hmi's. Actually the difference might be significant. Maybe closer to a 400 Joker (man those things are bright) which rates 1/3 of a stop less than the 575s according to Box.

As a key, I'd probably want the ability to drop 1K onto it, but maybe individually switching fixtures (if you are use 4x 250 halogens for example). As something other than a key, maybe the 500w is enough.

What about other variables?

Also, any pics of the rig we can check out?
 
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David,

Thank you for the number crunch, its great.

4 x 250 switchable is a combination I didn’t think of and would be pretty cool.
For weight/balance and cost, I think I’ll end up with 2 x 500 watt (for now).

I’ll post a pic with just the 500 (today), but bear in mind I’m DIY experimental and pretty broke, so this rig is built on a lawn mower chassis lol, but it’s solid and works like a champ.


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(I'm not real great at attachments, but I'll try.)

These pics show the 1st level of height/extension and some of the basic means of construction.

In the height pic the light is facing up. I made it with a large wing nut so its simple to loosen and face the light down or off to the side and tighten it back down.

The final two-light configuration will be on a T-bar and adjustable (somehow).

(A good stand would work just as well in most cases, but I don't have one and I didn't feel like making another camera jib with these "Materials".)


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Thanks guys. It’s very simple, and not ultra practical, but it’s okay.

The best thing about DIY film stuff is the way your neighbors will peek out their windows
like “Now WTF is THIS thing!?” :lol:


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Buddy Greenfield said:
I’ll post a pic with just the 500 (today), but bear in mind I’m DIY experimental and pretty broke, so this rig is built on a lawn mower chassis lol, but it’s solid and works like a champ.


-Thanks-
Click to expand...

That is awesome. Nice work.

Home Despot has 250w basic work lights for around $10 at the moment. I picked up one with a variety of mounting bits (grip clip, dirt spike, stand, and a hook) for around $14.

I love experimental lighting. I go digging through old bulbs at the salvage places around here from time to time for interesting practicals or other ideas. Hard part is finding ones that are still functional. :weird:
 
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David.rhsc said:
That is awesome. Nice work.

Home Despot has 250w basic work lights for around $10 at the moment. I picked up one with a variety of mounting bits (grip clip, dirt spike, stand, and a hook) for around $14.
Click to expand...

Thanks. I was thinking of getting two of the dual element (250w/500w) work fixtures, so I could have the flexibility of 250w- 500w- 750w - 1k with the same size/weight/balance configuration as 2 x 500w units.


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Thanks.

For projects like this (or a larger camera jib), an old lawnmower chassis is just begging for it.

The paint is Special Ops ultra low profile flat black on black, for covert DIY filmmaking –cus you never know when you might have to throw down. (99 cents at Walmart) :lol:


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