Superproducer Ted Hope on...

April 2, 2013

How to Make Cheap DIY Dimmer Switches for Your Film Lights

It's certainly not the sexiest piece of gear you're going to deal with, but dimmer switches can be unbelievably handy, especially if you have limited time and a limited budget, and you're already working with DIY lights. A dimmer switch, if you're not sure, is exactly what it sounds like: it's a way to selectively dim or brighten the quantity of a light source using electricity, rather than manual means like placing a net over the light. This is an important distinction as you're not trying to change the shape or quality of the light -- just simply lower the output. Most of these can be built for very little cost, so click through to check out some tutorials on building your very own dimmer switches.

Here is Film Force's tutorial for a dimmer switch:

Check out Film Riot's tutorial with a DIY China ball and dimmer switch (with some other bits after -- the video is a bit old):

Here is a dimmer tutorial from the The Frugal Filmmaker:

While it may look easy, it's also definitely easy to screw up if you're not paying careful attention -- and there is a risk of electrocution (as with anything electrical). It's also important that you get the correct gauge wire for the amount of electricity you're planning on putting through the dimmer. These can be a fire hazard if used improperly, so it's important that you know what kind of wattage you're shooting for before you actually build the light.

As was mentioned above, these work best with incandescent lights, as you can run into flicker issues with other light sources. Of course, these aren't just useful for filmmaking, as you can plug them into any lamp when they're not being used on your film set.

What do you guys think? For those who have built your own dimmer switches, what was your process like? Which style do you prefer?

Links:

Your Comment

24 Comments

It should be noted that these are limited to around 1K watts. They also cause the light to shift toward orange (and change spectral characteristics) as they dim down. This is why we (the royal we of the film industry) still prefer mechanical methods of lowering light levels (louvers and scrims). If you want a high CRI light with a neutral tone, it's often easier just to use a lower wattage bulb or fixture. I do see these used quite a bit even on big sets, though. Just my .02.

April 2, 2013

-1
Reply
Harry Pray IV

No shit, and a dimmer does not effect CRI on tungsten globes, just lowers color temp. Dimmers are great for practicals and china balls.

April 3, 2013

-1
Reply
kyle reid

Actually, grab your spectrophotometer and check. It actually DOES affect the CRI.

April 3, 2013

-1
Reply
Harry Pray IV

The fact that dimmers affect the color balance is exactly why I like to dim lights down. I'm actually sad to learn that kinoflo mini-flo no longer makes the 2900k, just the "correct" 3200k... I love using that, along with dimmed china balls for warmth on people. Corrected 3200k often looks flat and boring. Night tungsten light and direct daylight *shouldn't* look the same, but being exactly color balanced gives you that look.

April 7, 2013

0
Reply
Daniel Mimura

Are there any issues with sound when using dimmers? Can it introduce buzz into microphones and microphone lines?

April 2, 2013

1
Reply
Earnest reply

It seems to me that anything electrical could potentially introduce buzz into or otherwise interfere with microphones. It's one of the joys of sound.

Would love to hear from an expert in these matters, but I don't think dimmers would be more likely to cause interference than lights and cables.

April 2, 2013

-1
Reply

This kind of dimmer circuit is basically shutting the light off and on rapidly in ratio to how bright the light is supposed to be. It won't give off any radio frequencies or cause any issues with the ground, so I can't see where there would be an issue, although some people may hear a very high pitched sound while the dimmer is dimming.

It seems to me that since LEDs are DC, one could make an even simpler dimmer with a pot after the transformer that wouldn't strobe. Hmm...

April 3, 2013

-1
Reply

Cheap dimmers can and do transmit RF which is why they were never used in a recording studio. If the device has a "zero-crossing" circuit such as Lutron's do, the problem is eliminated...but they are $25 to $32 a pop.
Grateful Fred

April 4, 2013

1
Reply
Fred H. Nesbitt Jr

Thanks for the link. Was thinking about making these, and am very non-electrically-minded.

Recently did a cinematography course with a TV DP who, as a matter of course, when prelighting, hooked up EVERY light to a dimmer board, including the practicals. Seems like a sensible idea to me.

Now, trick No.2 -- at some point, I think I need to work out how to build remote control dimmers.

April 2, 2013

0
Reply

The best/ really only option to remotely control dimming is using a dimmer pack, and dimmer board connected via DMX control cable.

April 3, 2013

0
Reply
kyle reid

Storaro used dimmer boards quite a bit, so you're not in bad company there :)

http://www.theasc.com/magazine/jun98/storaro/pg3.htm

April 3, 2013

-1
Reply
GE

ommmgmggg this article reminds me of that one scene in Drive in the elevator where he makes out with the girl and then turns around the lights dim and get super dramatic and then he curb stomps the hitman.

I need to get me some dimmers.

April 3, 2013

0
Reply
john jeffreys

Also make sure that to check with local electrical guidelines and whatnot because if you build a dimmer that is 'illegal' or not rated for the wattage used on it and causes a fire that burns down a location your insurance company will likely laugh at you when you make your claim. And that's best case scenario with no one having been injured or killed in said fire.

Don't screw around with electricity if you don't know what you're doing. It only takes an Amp to kill you. Death is bad news.

Yes perhaps over dramatic but looking back at some of the shit I did in my youth like tying into breaker boxes and whatnot makes me realize how lucky I've been that nothing ever went wrong when there were so many opportunities for it do so.

Making electrical things for me is only second on my list of things not to do. 1st is to 'soundproof' a studio dirt cheaply using highly combustible foam material and then put hot lights in said studio.

I think I must be getting old.

April 3, 2013

0
Reply
Allan

That was my first thought as well. I mean buying a dimmer is not that expensive that I'd risk burning down a building for it.

Although, sometimes when I open up a cheap electrical device, I think "oh my god, I could have built that safer myself". However, like you said, it's all about the insurance. If you didn't built it, you are not personally responsible for it.

April 6, 2013

-1
Reply
Heiko

I'm electrotechnical, and I just like to share correct information. On regular electrical socket at home we have Alternating Current (AC), that means, we have 1 Phase and 1 Neutral OR 2 Phases. Positive and Negative is for batteries (Direct Current - DC).

There's too cinema lights that use DC, but they are expensive and you need a retifier, seems not to be the case.

April 3, 2013

0
Reply
Samuel Telles

I made one from a 400w house dimmer and it's very useful. HOWEVER, I wrote in texta all over it: "400w MAX" and I keep it hidden in a black bag when not in use. When doing short films, the gaffer will sometimes be a complete beginner...

April 3, 2013

-1
Reply
Russell Boyd

Here is the best and cheapest dimmer that I have found: http://www.harborfreight.com/router-speed-control-43060.html. It supports up to 1000 watts. I have been using several of them for a couple of years now.

April 3, 2013

0
Reply

Thanks! I might get a few.

April 3, 2013

1
Reply
Tom

Yeah, these work fine.

April 4, 2013

0
Reply
Tim Foster

I couldn't find the above model in Canada, so I got this: http://www.busybeetools.com/products/ROUTER-SPEED-CONTROL-115V-15A.html

It does dim my 600 and 420 watt tungsten lights, but the lights make a nasty hum at anything less than 100%, so I don't think I'll be able to use this dimmer very often.

June 22, 2013

0
Reply
Tom

All the dimmers I have come across gave off a humming sound when in use, so you'd always have to put them outside the room where you were actually filming and recording sound.

So now I rather use different ND gels and nets to "dim" lights.
And, as someone said before, there's always the possibility to switch a 600W bulb with a 300W bulb and voila, half the light without a color temperature shift. And when I want a warmer color temperature I can always add a 1/4 cto or cosmetic peach and do it more precisely than with a dimmer that always changes the intensity and the color temp at the same time.

In a studio with dmx dimmable lights of course I also use the dimmers because they don't ruin my sound (the dimmer packs also give off a loud humming noise, but they are not built into the same room of course).

April 6, 2013

1
Reply
Heiko

I love using dimmers, it's way easier to adjust that adding gels, especially on circular things like china balls for general ambiance. When I use them for non-specific general fill...having that absolute control (quickly---as opposed to swapping bulbs and adding/subtracting gels) is way more beneficial to me then their flaws). I only get buzzing that's too loud for sound when your bulbs are dimmed to 20% or less (roughly...with tungsten, you never know b/c every bulb is a little different...) but if a 500w photoflood is gonna be dimmed too far, I just use a 100w or 75w bulb. Nowadays I almost never have to use 500w photo floods anymore b/c sensors are so sensitive.

April 7, 2013

-1
Reply
Daniel Mimura

i need new video light ideas pls

July 2, 2013

0
Reply
nonso

An easier way to do this is to only cut and strip the side that does not have the grooves. I understand the need to just cut both wires but in doing so you have another chance for a short and fire hazard. I am sure you have thought about it and someone probably has said this in a comment. It is similar to the mechanism in an inline rotary click switch on a desk lamp, or fancy lamps. Just my .02.

January 6, 2014

0
Reply