Dimmer boxes for tungsten lights

<p>I shoot a lot of architecture, mostly with tungsten lights, and frequently use dimmers

to

adjust light levels. However, as far as dimmers go, there's simple lamp dimmers, fancy

theatrical lighting consoles, and really not much in between.</p>

 

<p>So I've had an idea to build a dimmer box which is better suited to still photography.

What

I'm wondering is, would anybody else be interested in something like this? Or have any

suggestions for useful features?</p>

 

<p>Here are the rough details:</p>

 

<ul>

<li>The box could have from 1-8 dimmer channels.</li>

<li>A channel could handle up to 300, 600, or 1000W, depending on the

type of dimmer. Obviously, you're limited by how much power you

can get out of a 15 or 20A circuit (1600-2300W); having 4 1kW dimmers

in a box wouldn't make much sense.</li>

<li>The slider controls could have marks at -1, -2, -3 stops.</li>

<li>The box would have a separate, undimmed channel for lights that don't

need to be dimmed.</li>

<li>The box would have a main switch, so you could turn all your lights off

or on at once. Useful for doing a multiple exposure (happens sometimes

when shooting interiors) or for breaking quicker for lunch :-)</li>

<li>The box wouldn't be too big, maybe 8"x5"x4" or smaller. Plus a 10'

main cord and a short cord and plug for each channel.</li>

<li>There's quite a few configuration options, so a box could be custom

made to fit your lighting requirements best.</li>

</ul>

 

<p>A few months ago I made something like this, only simpler, for another

photographer; we've both used them on several shoots now and have

found them pretty useful. You can control all your lights from one or

two places, and it's much easier to keep track of which light is which.

Otherwise, with a dozen lights and a bunch of lamp dimmers, you

usually get some pretty impressive rat nests.</p>

 

<p>So if there's some interest, I may make a few more and put them on Ebay

or something.</p>

 

<p>Comments?</p>

Jason,

First, sounds like a cool idea. I have made a few of these myself a while back for some "budget" lighting controls. (Mainly churches, friends, etc.) And had good results.

I don't know if you've thought about it or not But I see a couple areas of interest. Bullet # 3 The -1, -2 and -3 stops. As household dimmers (which it looks like you'll use) aren't linear in their dimming (meaning 1/2, or 1/3 (etc.) on the dimmer doesn?t put out 1/2 or 1/3 (etc.) the amount of light) you will need to measure these with a meter every dimmer every time you assemble a box to ensure accuracy. And bullet # 5 the main switch will need to be rated to handle the TOTAL amount of power coming into the dimmer box. If you have 2K coming in the box your main has to handle 2K. Most house switches handle 600W. You can get higher wattage, but you need to look and make sure.

Now some basic electrics: First you get roughly 2100W out of a wall. (I know the tech heads will figure I'm off...but it's close enough for the tolerances we have here.) That is without anything else being on it. (So be careful if adding a lot of fixtures?the breaker, or worse yet, fuse box may not be easy to reach.) Inside your box you will need at least 12Ga. wire throughout. And depending on how many outlets are in it will determine it?s overall size (NEC says how many wires of a given size can go in a box of a given size). Kind of along the same lines (those of the NEC) I would be VERY careful about selling these. Particularly to people you don?t know. You don?t know how they will use it. And IF (big IF I know) they (worst case) burn down??.oh let?s say an apartment building, full of people. And blame it on your dimmer box, you will be held liable for those people. Unless you get you boxes UL approved. (Very costly)

I know this is probably both more than and not what you really wanted to hear. But that was not my intention. Just be careful with electrics, especially when selling them to others.

 

Good luck,

Shawn Hooper

I use the dimmers for setting up, but you need full voltage for proper color temperature unless you shoot black and white.

I've seen plans for just such a setup in an old Petersen's Photographic "how to" guide book. Mine's in storage now, tho', along with most of my other photo stuff.

 

I can only advise you to be careful rigging up your owner dimmer array. It's not terribly difficult, especially with a guide on basic electrical wiring. But I did some volunteer work in a community theatre where the homemade dimmer board was ineptly constructed. There were steel girders directly over the tech booth and several people received nasty shocks when they touched the metal with their heads or hands while simultaneously adjusting the dimmers.

A pre WW2 method in the photobooks is to use a doublepole-doublethrow switch; to two AC sockets as outputs. Some movie sets use these; if on a budget. The sockets are in parallel in position P; and series in position S. In series the lights are only 60volts; if the loads are balanced. Here the tungstens run with less heat; and non-halogens have little color shift/dimming. The units I built for a catalog shoot decades ago have a standard AC duplex plug; ie normal premium house sockets; and a DPDT 20Amp switch; 12AWG wire or 10AWG if long. They are mounted in standard wall outlet boxes. These type of boxes were in photostores in the 1950's and 1960's too; when folks used tungsten Photoflood 3400K or 3200K lamps for home portraits; home movies; etc. Building your own equipment was more common then; folks didnt get all worked up about name brands; a micro spec of dust in a lens; plus strobes were very expensive too. I did several all day catalog shoots using tungstens in the 1960's. You adjust the lights at 1/2 power; then throw the switch for full power to just shoot the image. Then you drop back to 1/2 power; so the lights last radically longer (if non-halogen} ; and your objects dont get as hot. <BR><BR>You can also just get a Variac variable AC transformer too. Here the most used one is a 120 volt; 20Amp unit; that only cost me 30 bucks surplus; from a ham radio swap meet; TRW in El Segundo. They normally cost several hundred. They are also on EBAY too. You can dial in any AC voltage from 0 to 140 volts on mine. The tungstens can be dropped down to a low voltage; shadows and reflectors adjusted; then only 120AC used for the shooting.<BR><bR>Photo.net seems to be anti tungsten by a few jokers; you MUST by thousands of dollars worth of a strobes or designer lamps :) :) <BR><BR>ALOT of dimmers for household usage are limited to 600watts. These units are chopping up the AC waveform; and are not transformers or resistors. These are for regular bulbs; not fluorescents; not arc lamps.