What Watt for Continuous Lighting Portrait

Discussion in 'Lighting Equipment' started by melissa_demarco, Jul 26, 2010.

  1. I am very new to photography and I purchased continuous lighting umbrellas to take pictures of my kids, but I need to know what Watt bulbs I should get. Each stand holds 2 bulbs. Currently I have 2 45 Watt bulbs in each one equaling 180 watts. What should it be for portraits, to me it looks like i need brighter bulbs but wanted every ones opinions. Please help!
  2. I use 2, 1000watt bulbs. But you can do it with one 100 watt household bulb in a reflector.
  3. 2000 watts seems like a lot, and hot. I will try the 100 watt bulb :) Thanks for the advise!
  4. Note that I presume your stands at present have CFLs (compact fluorescent lamps) in them. You can certainly replace these with larger CFLs if they will physically fit (although 45 watts is already quite large for a CFL) but do not under any circumstances replace the CFLs with older-type Photoflood or Photopearl bulbs, as these run very hot and also take a lot more current and will almost certainly melt your lampholders!
  5. The issue, Melissa, is in having enough light to let you shoot with a low enough ISO to keep your images from looking noisy while still being able to get a fast enough shutter speed to avoid seeing motion blur. Motion blur can come from you moving your camera during the exposure (simple: use a tripod!), or it can come from the subject moving during the exposure (not simple: these are kids you're talking about). So, the brighter the light source, the faster you can get that shutter speed.

    Depending on the focal length of the lens you're using, you probably don't want a shutter speed any slower than 1/125th (though faster is better). This is also going to get tangled up in the other thing that impacts exposure: your lens aperture. You can open that lens up to a wider aperture and get by in lower light, but you lose depth of field, and possibly some sharpness.

    More light is essentially always better. It gives you more options, allows you to work with the lights a bit farther back from your subjects, and more. That 100 watt bulb would be, for me, an absolute bare minimum when trying to shoot young, wiggly subjects. I'd prefer many times that much light, really. Hence, strobes, for most people who find themselves doing much of this.
  6. First off, your maximum bulbs might be dictated by the lighting fixtures and/or the household electric circuit they're plugged into. The suggestion of 1000 Watt bulbs can raise major issues. For example, garden-variety household lamps and lighting fixtures usually have a sticker, indicating the maximum power bulb they can use, usually between 60 and 150 Watts. More than that and they can be a fire hazard. Check the rating on your equipment; 1000 Watts may be fine but may be a fire waiting to happen. Also, using 4 x 1000 Watt bulbs requires about 30 or 35 Amps; most household circuits are only good for 10 or 15 or maybe 20 Amps, which would mean with four bulbs, even assuming nothing else is using the circuit, each bulb might be limited to 300 to 600 Watts.
    Second, by a large measure, not all lights of the same power consumption (Watts) are created equal. There are major differences in light output (usually rated in lumens on regular bulbs) per Watt; generally, fluorescent bulbs put out a lot more light per Watt than incandescent (regular-type) bulbs do, and there are other types of lights, too. Also, different bulbs put out very different colors of light, which was more of an issue with film, but is still an issue with digital.
    I agree that (within reason) more light is better. You're unlikely to get too much light with a home continuous-lighting setup (although posing under them can get hot). Read the manual and see what the manufacturer recommends, both in terms of maximum power consumption (Watts) and in terms of bulb types. Also, you will get better results if you can use a gray card to set a custom white balance for your particular bulbs (and reflectors).
  7. I'm hoping the umbrellas are shoot through and not bounce, because bouncing light into an umbrella with a continuous light source is going to require a huge amount of power. You may want to try using one with a shoot through umbrella and the other with no light modifier so that your lighting isn't flat.
    I presume with the 45 watt lights you're talking compact fluorescent? If so a total of 180 watts is a decent amount of power, provided you have the lights relatively close to your kids and you bump your ISO up to probably 400. I would suggest avoiding incandescent lights, especially with kids, as they get very, very hot, and if one gets knocked over you could wind up with some serious burns, not to mention that if your umbrella isn't designed for incandescent, you could start a fire.

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