Tuesday, March 22, 2011

Man, Those Lights Are Hot!

I received a few questions about what lights we used in the Bambi Cantrell workshop at CreativeLIVE this past weekend.

One of the questions was how did we connect the camera to the lights to sync them. We didn't. For this workshop we used continuous hot lights. We used a mixture of Bambi's Chimera Triolets and my Photoflex Starlites. These lamps can use either a tungsten bulb or a fluorescent bulb. The tungsten bulbs are rated at 3200° Kelvin and the fluorescent bulbs are 5600° Kelvin (daylight). The tungsten lamps run extremely hot and you need to have leather gloves on if you need to make adjustments. They are available in various wattages from 250 to 1000 watts. We used 500 watt lamps in the two strip lights and the medium softbox, and we used a 1000 watt lamp in the Octabank. The fluorescent lamps run much cooler and are easier to handle. The one pictured below (not used in the workshop) is 150 watts, and puts out about the same amount of light as a 450 to 500 watt tungsten lamp.

Chimera Triolet lamp head with a 500 watt tungsten lamp mounted in a softbox.
Photoflex Starlight QL with a 1000 watt tungsten lamp
Photoflex Starlight QL with a 150 watt fluorescent lamp
Using continuous lighting means that we don't have to sync up the camera shutter with a flash. These are like big-brothers to your standard household tungsten and fluorescent lamps. They have advantages and disadvantages when compared to strobe lighting:

  • Continuous. You see exactly what you are going to get. Easier to use for photographers who are new to studio lighting.
  • Inexpensive. Relative to high end electronic flash units.
  • Brightness. Not as bright as strobes. You can easily work at low apertures (1.4, 2.8, etc.) to get limited depth of field much easier than you can with high powered electronic flash.
  • HOT! You can easily get a bad burn if you grab the head or bulb before it has had a chance to cool off
  • HOT! Used in close to your models, they can become uncomfortable.
  • HOT! If you are photographing food, the lights can dry out the subjects.
  • HOT! You need specially designed soft boxes that can withstand the heat and not catch on fire.
  • Brightness. Even at 1000 watts you need to use high ISO values (400 or more), which can lead to grain/noise issues. You are also limited to slow shutter speeds, which can lead to camera shake if you don't have steady hands or a tripod.
Electronic flash units (also called strobes) often have tungsten modeling lamps to help see how the light falls. These can range from 100 to 500 watts, so they can run hot, too. But most flash heads that use modeling lamps have fans in them to help keep them cool. Neither of the continuous lamp heads we used had fans.

An important thing to keep in mind when working with tungsten lamps is to not touch them with bare hands/fingers, even when cool. The oils on your skin will transfer to the quartz glass which can lead to a weakening of the glass, which can lead to premature failure of the bulb or even to the bulb exploding. Not something you want to happen, especially if you have a human subject on the set. The 1000 watt bulb you see in the photo above has a protective glass enclosure around the quartz glass, so it would be OK to touch.

Here you can see a typical 150 watt tungsten halogen modeling lamp that is made of quartz with no glass cover. Do not touch this type of lamp with bare hands:

And here is a 1000 watt bulb that doesn't have a glass cover which shows the effect of having been touched:

If you have any questions about the equipment we used in Bambi's workshop on CreativeLIVE please send me a note and I'll do my best to answer it.

1 comment:

  1. Wow - this is great, John, especially for someone like me, with exactly zero experience with lights. Given all that was going on this weekend, this was an area I didn't pay as much attention to, so it's nice to get the behind-the-scenes scoop :)


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