new lights or dimmers? at DVinfo.net
DV Info Net

Go Back   DV Info Net > The Tools of DV and HD Production > Photon Management

Photon Management
Shine an ever-loving light on you.

Reply
 
Thread Tools Search this Thread
Old April 11th, 2007, 06:14 AM   #1
Inner Circle
 
Join Date: Nov 2004
Location: Baltimore, MD USA
Posts: 2,337
new lights or dimmers?

Hi,

I use a Mole Richardson biax-4 for a key light and have recently been given two fixtures with 650 W lamps. They're great but 650 is a lot of light. Is it better to get smaller lights or dimmers? If dimmers, which ones?

Thanks,

Ty Ford
Ty Ford is offline   Reply With Quote
Old April 11th, 2007, 06:26 AM   #2
Inner Circle
 
Join Date: Oct 2004
Location: Port St. Lucie, Florida
Posts: 2,614
I would get dimmers as you can turn the big lights down, but you can't turn a small light up. The controllers range from very expensive to cheap.

I have three router speed controls, bought from Harbor Freight. I got them on sale for less than $20.00. The are 1500 watt and have full and variable controls. They work excellent! No problems at all. You have to look hard for them as they are sold out just about as fast as they come into stock. I think yo could order them on-line but the price will be about $29.00 I think. A bargain either way.

Mike
__________________
Chapter one, line one. The BH.
Mike Teutsch is offline   Reply With Quote
Old April 11th, 2007, 09:47 AM   #3
Inner Circle
 
Join Date: Feb 2006
Location: Belfast, UK
Posts: 6,143
Only problem with dimmers is you change the colour temperature. You could buy some scrims (metal nets) which will reduce the light output. They're pretty standard pieces of kit and you can get different grades. Another alternative are ND gels.
Brian Drysdale is offline   Reply With Quote
Old April 11th, 2007, 10:07 AM   #4
Regular Crew
 
Join Date: May 2004
Location: Wash. DC area
Posts: 154
Dimmer RF

Ty,
Not sure about the Harborfreight dimmers, but many cheap diy/hardware store units will create RF problems for audio.
Test,test, test etc.


chris li/bethesda DP
Chris Li is offline   Reply With Quote
Old April 11th, 2007, 10:37 AM   #5
Regular Crew
 
Join Date: Jan 2007
Location: Boca Raton, Florida
Posts: 116
Harbor Freight dimmers

Hi:

Noticed the thread and thought that I would add my two cents.

I have a handful of the Harbor Freight Dimmers, recently on sale for $9.99, and have not found them to introduce any RF interference at all. They work great with the Arri system and for the price, cannot be beat. The only caveat is the fact that they do not have a calibrated dial.
Ronald Wilk is offline   Reply With Quote
Old April 11th, 2007, 12:38 PM   #6
Major Player
 
Join Date: Aug 2002
Location: Albuquerque, New Mexico USA
Posts: 287
I'd vote for dimmers too. While the color shift when dimming tungsten units is real, it doesn't become much of an issue until you are down below something like 50% on the dimmer. With a few scrims in your kit, you can usually get what you need without much change in color temp. Dimmers are fast and let you dial in exactly what you need.

Almost any dimmer will work for 650W units. Even do-it-yourself Home Depot dimmers can handle that, although the possibility of RF noise does exist. I carry a pair of AC in-line Quick Dimmers from Bill McIntire's "Magic Gadgets" website. They'll handle 2K watts with ease, are small, light weight, absolutely quiet, and built like a tank. Their only downside is cost.
Ralph Keyser is offline   Reply With Quote
Old April 11th, 2007, 01:05 PM   #7
Regular Crew
 
Join Date: Dec 2006
Location: Tampa-Orlando, FL
Posts: 124
There was a recent very informative conversation on the B-Roll forum about dimmers. Check it out.

http://b-roll.net/forum/showthread.p...hlight=dimmers


Nino

www.EFPlighting.com
Nino Giannotti is offline   Reply With Quote
Old April 12th, 2007, 11:12 PM   #8
Major Player
 
Join Date: May 2004
Location: Louisville, KY
Posts: 378
yeah, I think lights start changing color temp around 50%....at least that's what my teacher told us in basic tv. I don't know how a dimmer could add interfernce either since a dimmer adds more resistance. On old cars there where radio problems because the spark plugs had next to no resistance and you could hear the plugs firing through speakers. When cars moved to plug wires with resisatnce in them the unwanted noise in the speakers quit. (the plugs originally used like +8000 volts).
Eric Stemen is offline   Reply With Quote
Old April 13th, 2007, 12:54 AM   #9
Trustee
 
Join Date: Jan 2004
Location: Scottsdale, AZ 85260
Posts: 1,538
Ty,

My "order of priority" for lowering the amount of light hitting any subject is as follows.

Use a scrim
Move the light farther away
Use N/D gel
Use a dimmer

The scrim is simple, quick, inflamable, and doesn't screw ANYTHING else up when you use it. Plus a one stop scrim will reliably lower your light one stop. No more or less. It just knocks back the light, PERIOD.

Moving the light farther away is similarly without negatives, UNLESS, of course, you can't move the light - which happens.

ND is similarly pretty effective, but it takes a bit more time to rig and on a hot light like a 1K Tota or other open face insturment, even quality theatrical gel has a melting point.

The dimmer is LAST on my list because over the years the use of dimmers has screwed me up more than any other solution. Audio effects, color shift, or just some knucklehead kicks the dimmer and no matter HOW I try to re-adjust it to where it was on the first 3 takes, the damn shots NEVER match in post.

I'm not saying they aren't nice to have around and they're often useful. But just know that when you use them, you're putting one more "variable" in play on your set.

Your mileage may vary. Good luck.
Bill Davis is offline   Reply With Quote
Old April 13th, 2007, 04:11 AM   #10
Inner Circle
 
Join Date: Nov 2004
Location: Baltimore, MD USA
Posts: 2,337
Quote:
Originally Posted by Eric Stemen View Post
I don't know how a dimmer could add interfernce either since a dimmer adds more resistance.
Silicon control rectifiers in dimmers generate noise as a byproduct of the way they rip portions of the AC sine wave in order to lower the energy (dim) the light.

I hear that noise when cheap (residential) Leviton dimmers are used.

Regards,

Ty Ford
Ty Ford is offline   Reply With Quote
Old April 13th, 2007, 06:46 AM   #11
Wrangler
 
Join Date: Oct 2003
Location: DFW area, TX
Posts: 6,117
Images: 1
Quote:
Originally Posted by Ty Ford View Post
Silicon control rectifiers in dimmers generate noise as a byproduct of the way they rip portions of the AC sine wave in order to lower the energy (dim) the light.

I hear that noise when cheap (residential) Leviton dimmers are used.
Quite right, Ty. The best dimmer (although pricey), is the VARIAC. It is a variable AC transformer and can be bought in many size/ratings. The other downside is that these are kind of heavy.

http://www.variac.com/staco_Variable...former_Map.htm

-gb-
Greg Boston is offline   Reply With Quote
Old April 13th, 2007, 06:54 AM   #12
Trustee
 
Join Date: Dec 2006
Location: Little Rock
Posts: 1,383
Another option would be to replace the 650w lamp with a lamp of similar design, but less wattage.
David W. Jones is offline   Reply With Quote
Old April 13th, 2007, 07:15 AM   #13
Inner Circle
 
Join Date: Nov 2004
Location: Baltimore, MD USA
Posts: 2,337
Thanks for that David,

I have already come down to 650 from 1 kW (boy is that bright!).

Don't know if they make, what, maybe 250-300 watt bulbs for these fixtures.


Regards,

Ty
Ty Ford is offline   Reply With Quote
Old April 13th, 2007, 02:54 PM   #14
Major Player
 
Join Date: May 2004
Location: Louisville, KY
Posts: 378
Thanks for the info Ty Ford.
Eric Stemen is offline   Reply With Quote
Old April 16th, 2007, 06:45 PM   #15
Major Player
 
Join Date: Jan 2007
Location: Gainesville, FL
Posts: 201
Harbour Freight

I hear the whining when I dim a bulb with the cheapo router speed control. My longer tube type bulbs make more noise than the smaller peanut type bulbs. They might be ok with the speed control, but I can hear some noise up close, for reasons mentioned before.

For a more technical pov and possible fix from another web site "The inductor slows the rise time of the AC wave when it turns on. In turn this provides two functions: 1) it reduces EMI (electromagnetic interference) created by the sudden rise in voltage in the wires, and 2) stops light bulb filaments from rattling. When you turn the typical home dimmer down low, you can hear a buzz in the light fixture - that is the filaments rattling as the voltage is suddenly applied to the bulb.

I'll dig up my digital electronics book and maybe ask my former instructor if there is a cheap fix.
Larry Vaughn is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

B&H Photo Video
(866) 521-7381
New York, NY USA

Scan Computers Int. Ltd.
+44 0871-472-4747
Bolton, Lancashire UK


DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > Photon Management

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



All times are GMT -6. The time now is 06:29 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2024 The Digital Video Information Network